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Image source: The Motley Fool. Tuesday, Aug. 11, 2026 at 4:30 p.m. ET Vice President of Corporate Communications and Investor Relations - Hayleigh Collins Chief Executive Officer - Sean Nolan President and Head of R&D - Sukumar Nagendran Chief Financial Officer - Kamran Alam Operator: Hello, and welcome to the Taysha Gene Therapies Second Quarter 2026 Financial Results Conference Call. [Operator Instructions] Please be advised that today's conference is being recorded. It is now my pleasure to introduce Vice President of Corporate Communications and Investor Relations, Hayleigh Collins. Hayleigh Collins: Thank you. Good afternoon, and welcome to Taysha's second quarter 2026 financial results and corporate update conference call. Earlier today, Taysha issued a press release announcing financial results for the quarter ended June 30, 2026. A copy of this press release is available on the company's website and through our SEC filings. Joining me on today's call are Sean Nolan, Taysha's Chief Executive Officer, Sukumar Nagendran, President and Head of R&D; and Kamran Alam, Chief Financial Officer. We will hold a question-and-answer session following our prepared remarks. On today's call, we will be making forward-looking statements, including statements concerning the potential of TSHA-102, including the reproducibility and durability of any favorable results initially seen in patients dosed to date in clinical trials, including with respect to functional milestones, to positively impact quality of life and alter the course of disease in the patients we seek to treat. Our research, development, and regulatory plans for our product candidates, including the timing of initiating additional trials, reporting data from our clinical trials, and making regulatory submissions, timing or outcomes of communications with the FDA on the regulatory pathway for TSHA-102, the potential for product candidate to receive regulatory approval from the FDA or equivalent foreign regulatory agencies. Our ability to realize the benefits of breakthrough therapy designations for TSHA-102, our ability to drive long-term value for stockholders, and the market opportunity for our programs. This call may also contain forward-looking statements relating to Taysha's growth, forecasted cash runway, and future operating results, discovery and development of product candidates, strategic alliances and intellectual property, as well as matters that are not historical facts or information. Various risks may cause Taysha's actual results to differ materially from those stated or implied in such forward-looking statements. For a list and description of the risks and uncertainties that we face, please see the reports we filed with the SEC, including our annual report on Form 10-K for the full year ended December 31, 2025, that we filed on March 19, 2026. This conference call contains time-sensitive information that is accurate only as of the date of this live broadcast, August 11, 2026. Taysha undertakes no obligation to revise or update any forward-looking statements to reflect events or circumstances after the date of this conference call, except as may be required by applicable securities laws. With that, I would now like to turn the call over to our CEO, Sean Nolan. Sean Nolan: Thank you, Hayleigh, and welcome everyone to our second quarter 2026 financial results and corporate update conference call. On today's call, I will begin with an update on our recent clinical, manufacturing, and commercial readiness activities. Dr. Suku Nagendran, President and Head of R&D, will then discuss data presented at the recent IRSF Rett Syndrome Scientific Meeting, which strengthens the clinical and scientific foundation of the TSHA-102 program. Kamran Alam, our Chief Financial Officer, will follow up with a financial update, and I will then provide closing remarks before opening the call up for questions. The second quarter of 2026 was a highly productive period for Taysha. We continued to execute against our clinical development strategy while advancing key manufacturing and commercial readiness initiatives as we move toward a potential BLA submission for TSHA-102. We achieved several important milestones, including the completion of dosing in both the REVEAL pivotal and ASPIRE trials, as well as the presentation of compelling longer-term Part A data from the REVEAL Phase I/II trials. Beyond the clinical development, we expanded our partnership with Catalent to include future commercial manufacturing support for TSHA-102, completed payer research to inform further market access planning initiatives, continued to build our leadership team, and strengthened our balance sheet through a successful follow-on financing that is expected to support our planned activities into the second half of 2028 and through potential BLA approval. Collectively, we believe these accomplishments place us in a position of strength as we approach the planned 6-month interim analysis from the REVEAL pivotal trial, continue our engagement with the FDA, and advance commercial readiness activities. I will begin with a clinical update. We continue to execute with discipline across our REVEAL pivotal and ASPIRE trials and are pleased with the significant progress made to date. In June, we announced the successful completion of dosing in the over-enrolled REVEAL pivotal trial with a total of 17 patients dosed with TSHA-102. Importantly, similar to our REVEAL Part A trials, we enrolled a well-balanced distribution of ages across pediatric, adolescent, and adult patients that's reflective of the broader Rett syndrome population. We believe this allows us to generate a comprehensive data set that may support a broad label for TSHA-102. Once all 17 patients in the pivotal trial complete 6 months of follow-up, we will conduct a 6-month interim analysis, which may serve as the basis for our planned BLA submission and potentially accelerate our submission time line by at least 2 full quarters relative to filing on the 12-month data. Given our longer-term Part A data substantially exceeded the FDA-aligned 33% minimum efficacy threshold established for the pivotal trial, we believe this further strengthens the potential for regulation based on the most current trial analysis. I also want to share that as of July, we have completed dosing in our ASPIRE trial, where we treated 4 patients aged 2 to less than 4 years old with TSHA-102. ASPIRE is primarily a safety-focused and to support a broad label for patients aged 2 years and older with Rett syndrome as part of our planned BLA package. In addition to generating supportive safety data, ASPIRE is designed to provide insight into the impact of early intervention, including the potential to reverse disease manifestations and restore function while also preventing further disease progression in younger patients. With dosing now complete in both trials, we are laser-focused on preparing for the pivotal trial interim analysis and subsequent discussions with the FDA to inform next steps toward a BLA submission. We expect to provide an update on both fronts in the first half of 2027. We continue to believe the increasingly robust body of evidence generated across the program strengthens the rationale for this potentially expedited submission plan. Turning to safety, both high and low dose TSHA-102 continue to be generally well-tolerated. There have been no severe treatment-related serious adverse events or dose-limiting toxicities observed since the clinical trial began over 3 years ago across the 33 patients treated in the REVEAL Phase I/II pivotal and ASPIRE trials as of the August 2026 data cutoff, supporting a favorable and consistent safety profile. In early July 2026, over the holiday weekend, 1 patient in the REVEAL pivotal trial experienced a single moderate Grade 2 treatment-related adverse event of peripheral sensory neuropathy, an expected AAV-associated risk approximately 6 weeks after treatment. Consistent with the treating institute's policy, the patient was admitted overnight for management and observation, thus resulting in a technical classification of the Grade 2 event as serious adverse event. The patient was discharged the following day, and importantly, rapidly demonstrating substantial recovery. Clinical trial dosing is now complete, and we have surpassed 3 years since the first patient received TSHA-102. To date, 33 patients spanning a broad range of ages, genotypes, and disease severities have been treated, with no severe treatment-related serious adverse events or dose-limiting toxicities reported. The safety profile of TSHA-102 has remained encouraging with a consistent benefit to risk profile throughout the program. I would like to recognize the expertise and vigilance of our participating principal investigators, the rigorous training and oversight provided by our clinical development and clinical operation teams, as well as our CRO partner, and importantly, the commitment of the patients and caregivers whose participation in the trials and dedication to help ensure the best possible outcomes for the Rett syndrome community. Based on the totality of the data generated to date, including the favorable safety profile and compelling efficacy data from the longer-term follow-up from the REVEAL Part A, we continue to believe TSHA-102 has the potential to be a differentiated and transformative therapy for a broad population of patients with Rett syndrome who continue to face high unmet medical need. The strengthened body of evidence supporting TSHA-102 was highlighted at this year's IRSF Rett Syndrome Scientific Meeting, where we presented data that collectively reinforced the clinical and scientific foundation of our development program and registrational strategy. Suku will discuss the data in greater detail shortly, but before I turn the call over, I wanted to touch on our ongoing commercial readiness efforts. We have continued to make meaningful progress in preparation for a potential launch. This past quarter, we completed payer market research, which demonstrated strong support for TSHA-102's value proposition and reimbursement potential. Specifically, the research demonstrated that TSHA-102 was viewed as a high-value therapy due to its transformative disease-modifying potential in a population with significant unmet need. Coupled with the convenience of a onetime intrathecal administration that is less invasive than other direct-to-CNS approaches and can be administered in a broadly accessible outpatient setting. Importantly, payer willingness to provide coverage was primarily driven by the potential for TSHA-102 to deliver durable, clinically meaningful benefits. Payers consistently emphasized the importance of demonstrating durable functional gains and improvements that translate into real-world benefit for patients and caregivers, areas where we believe the growing body of clinical evidence supporting TSHA-102 is particularly compelling and differentiating. Finally, the research demonstrated that strong efficacy, safety, and durability are expected to be the primary drivers of coverage and support reimbursement, with durable functional improvements serving as the most important determinant of value. These findings reinforce our confidence in TSHA-102's commercial potential and reimbursement outlook. We are leveraging these insights to further refine our market access strategy and support a successful potential commercial launch. In tandem with our market access strategy, we have also expanded our longstanding partnership with Catalent, the leading global contract development and manufacturing organization. Catalent will serve as our primary commercial manufacturing partner following potential FDA approval of TSHA-102. This expanded agreement secures a long-term commercial manufacturing capacity and establishes a scalable supply framework intended to support TSHA-102's potential launch and future demand. Under the agreement, manufacturing will be conducted at Catalent's FDA-licensed gene therapy campus in Harmans, Maryland, which is an established AAV manufacturing facility with significant commercial expertise. Catalent will leverage its experience across more than 90 gene therapy programs, including multiple commercial products. With BLA-enabling process performance qualification activities underway, we believe we have established a strong manufacturing foundation necessary to support the anticipated significant demand for TSHA-102 following its potential launch and commercialization. Finally, we continue to strengthen our organization through the key leadership hires that position us for the next phase of growth. This includes the recent appointment of Mike Johannesen as Chief Legal Officer. Mike brings more than 3 decades of experience across corporate law, governance, compliance, and strategic transactions, including extensive leadership experience in the gene therapy space. His tenure at Advanced Medicine Partners, Jaguar Gene Therapy, and AveXis will be instrumental as we execute on our strategic priorities and continue to evolve the organization. I would now like to turn the call over to Suku to dive deeper into our recent data presentations at the IRSF Scientific Meeting. Sukumar Nagendran: Thank you. As Sean highlighted, we've achieved several important milestones supporting the advancement of TSHA-102 towards potential registration, including the successful completion of dosing in both the REVEAL and ASPIRE trials, as well as multiple data presentations at the IRSF Scientific Meeting supporting TSHA-102. Importantly, these data sets reinforce our confidence in the program and collectively support the transformational potential of TSHA-102 to deliver durable real-world benefits to patients. We presented longer-term REVEAL Part A data, where all 12 patients treated had at least 12 months of follow-up data as of the May 2026 data cutoff, enabling a more comprehensive assessment of the durability, depth, and consistency of treatment effect over time. The data continue to demonstrate broad multi-domain functional impact that deepened over time through greater than 12 months post TSHA-102. We're particularly encouraged by the durability and deepening of the treatment effect. Notably, we have not observed evidence of plateau effect with data continue to trend upwards over time. Using the FDA-aligned developmental milestone assessment criteria that serves as the primary endpoint in the REVEAL pivotal trial, results from Part A far exceeded our FDA-aligned pivotal response rate threshold of 33%, with a 75% response rate seen as early as 3 months and increasing to 83% at 6 months. By 12 months, 100% of the 12 patients were responders. These results further bolster our confidence going into the upcoming 6-month interim analysis of the REVEAL pivotal trial. We have observed a consistent and clinically meaningful treatment effect across the pediatric, adolescent, and adult patients treated. Across the 6 pediatric patients evaluated, 16 total developmental milestones were achieved. And among the 6 adolescent and adult patients, 15 developmental milestones were achieved. Together, patients achieved a total of 31 developmental milestones. Given that over 85% of the prevalent Rett syndrome population is older than 10 years of age, we are particularly encouraged by the consistency observed regardless of age or disease severity that supports the commercial opportunity for TSHA-102. In addition to the consistent treatment effect across age groups, we've observed broad functional impact across core disease domains of Rett syndrome. At 12 months and beyond, patients demonstrated a total of 310 functional gains across communication, fine motor, gross motor, and autonomic domains, averaging 26 gains per patient. These gains included both naturally defined developmental milestones as well as additional skills and improvements that meaningfully impact daily life, such as enhanced motor skills and hand use, the ability to respond to questions, reduced seizure activity, and decreased hand stereotypies, to name just a few. Collectively, these findings reinforce our belief that TSHA-102 has the potential to provide meaningful therapeutic benefit across the broad Rett syndrome population and deliver tangible gains in independence and quality of life for patients and caregivers. We continue to be encouraged by the favorable safety profile of TSHA-102, with no severe treatment-related SAEs or DLTs across the 33 patients treated as of the August 2026 data cutoff. The safety profile of TSHA-102 has remained encouraging, the consistent benefit to risk profile throughout the program. To that end, I would like to recognize our participating principal investigators for their clinical expertise and diligence in patient care, and thank our clinical development and clinical operations teams and CRO partner for their exceptional training, proactive monitoring, and commitment to maintain the highest standards of patient safety and trial execution throughout the study. In addition to the clinical data, we also presented analysis from the Rett syndrome natural history study supporting the design of the REVEAL pivotal trial. The data demonstrated a clear developmental plateau after 6 years of age, with the likelihood of gaining or regaining a developmental milestone that was lost after a defined number of years declining sharply to less than 6.7%. These results support the minimum inclusion age of 6 years in our well-controlled, single-arm interventional trial evaluating gain and regain of developmental milestones. We also further strengthen our confidence that the developmental gains observed in REVEAL are meaningful and distinguishable from the expected natural history of the disease in patients 6 years and older. We also presented methods evaluation study data supporting the developmental milestone assessment, DMA for short, as a psychometrically valid and FDA-supported primary endpoint for single-arm interventional studies. Prior to initiating REVEAL, the DMA was evaluated in a multi-site, noninterventional study to assess its applicability as a clinical outcome measurement in a registrational study. These findings were shared with and reviewed by the FDA as part of the trial protocol developmental discussion and strengthen our confidence in the integrity and interpretability of the data set we expect to generate from the REVEAL pivotal trial. Finally, we presented previously reported preclinical data supporting the design of the TSHA-102 construct. The data demonstrated that Taysha's miniMeCP2 is functionally comparable to full-length MECP2 across molecular and biochemical functions. In addition, Taysha's self-complementary AAV9 vector enables superior MECP2 expression compared to a single-stranded AAV9. This supports our construct design and ability to achieve broad effective delivery to the central nervous system through the minimally invasive intrathecal administration approach, which as Sean Nolan referenced earlier, is of particular importance to care. Taken together, the durability and breadth of the clinical responses observed to date, consistency in response across patient populations, supportive natural history analysis, and psychometric validation of the DMA pivotal trial endpoint, together with a favorable safety profile, continue to position TSHA-102 as a potentially transformative therapy. I'll now turn the call over to Kamran Alam to review our financial results. Kamran Alam: Thank you, Suku. Research and development expenses were $38.6 million for the 3 months ended June 30, 2026, compared to $20.1 million for the 3 months ended June 30, 2025. The $18.5 million increase was primarily driven by BLA-enabling PPQ manufacturing initiatives performed during the 3 months ended June 30, 2026, and higher clinical expenses from the REVEAL and ASPIRE trials. Compensation expenses, including noncash stock-based compensation, also increased as a result of additional research and development headcount. General and administrative expenses were $12.1 million for the 3 months ended June 30, 2026, compared to $8.6 million for the 3 months ended June 30, 2025. The increase of $3.5 million was primarily due to higher compensation expenses, including noncash stock-based compensation expense, and increases in consulting and professional fees, including commercial launch readiness initiatives. Net loss for the 3 months ended June 30, 2026, was $46.6 million or $0.13 per share compared to a net loss of $26.9 million or $0.09 per share for the 3 months ended June 30, 2025. As of June 30, 2026, Taysha had $455.4 million in cash and cash equivalents. This reflects the gross proceeds of $230 million from the June 2026 follow-on financing, including full exercise of the underwriter's option to purchase additional shares. We expect that our current cash resources will support planned operating expenses and capital requirements into the second half of 2028. I will now turn the call over to Sean for his closing remarks. Sean? Sean Nolan: Thank you, Kamran. We believe the growing body of evidence supporting TSHA-102 further strengthens its path toward potential registration and our commitment to bringing this potentially transformative therapy to a broad population of patients with Rett syndrome. We believe the continued progress across our clinical manufacturing and commercial readiness initiatives, combined with our strengthened balance sheet, positions us well as we approach the REVEAL pivotal 6-month interim analysis, continue our engagement with the FDA, and prepare for the potential BLA submission and commercialization. We remain on track to complete the BLA-enabling PPQ campaign in the fourth quarter of 2026, and we anticipate reporting top line data from the REVEAL pivotal trial 6-month interim analysis and FDA feedback on the BLA submission pathway in the first half of 2027. I will now ask the operator to begin our Q&A session. Operator? Operator: [Operator Instructions] Our first question comes from the line of Kristen Kluska with Cantor Fitzgerald. Kristen Kluska: The one I wanted to ask was on your payer research. Obviously, they see the potential of this therapy and the unmet need, but you made some comments around the onetime IT administration procedure in particular. Curious if there was anything specific they said about that kind of procedure and the outpatient that was important in the payer discussions. And yes, how we should be thinking about the specifics behind that? Sean Nolan: Yes, Kristen, thanks for the question. There will be more to come on this. I would say this is the second step in our payer discussions. More to come later this fall, and hopefully, we can provide more updates as time goes on. But the number one in terms of high value, as you would expect, the focus was primarily on the potentially transformative data set that we have. And they really like this idea of the milestones and being able to demonstrate functional gains and improvements that have never been demonstrated before. So this also highlighted the strength and the robustness of the natural history analysis that we did because it really contextualized for the payers what they were getting for the money that would be spent on the therapy. The second thing was around the durability and the fact that, at this point, we could share with them that we have at least 3 years' worth of data in our patients. By the time we get to market, that's going to be closer to 4-plus, 5 years, things of that nature. And obviously, that meant a lot to them. And the safety aspect was another one, too. And they liked the fact that we've continued to demonstrate that overall, this is a well-tolerated gene therapy. So that combination of the product offering really resonated in the context of a high unmet need, rare disease with nothing that has been demonstrated to truly transform outcomes in patients. The IT piece was something they definitely anchored to because of the fact that they realized that this is a much less invasive route of administration versus other ways to go direct to the CNS. They know that because of this administration aspect, that the reimbursement is going to be on the outpatient side, and so those are going to be attractive margins for those folks. And they also realize that when you start thinking about the scalability of it, you can get to more patients with this. So as they thought about the economics, they can see how the outpatient reimbursement could be quite attractive to them, relative to other potential administrations with other gene therapies that are out there. Hope that helps. Operator: Our next question comes from the line of Salveen Richter with Goldman Sachs. Salveen Richter: Can you help us further understand the Grade 2 SAE? You noted that this is an expected AAV-associated risk, but how do you mitigate this risk going forward, and how frequent are these type of events for gene therapies that leverage AAV9? Sean Nolan: Yes, Salveen, great question. I think a few things for context here. Number one, the Rett population in general, there's data on this. Over 50% of Rett patients have peripheral neuropathies as part of the disease course. Number two, as you stated that AAV9 does have a -- it's a known effect of AAV9 that you can see peripheral neuropathies, and there's multiple product labels where that's indicated. It's not unexpected here. In this particular case, it was a Grade 2, which is a moderate event. I would say that in terms of the management of this, I would ask Suku to comment on that. But from what we see from the product profile, the balance between risk and benefit really tilts heavily on the benefit side here, without question. We were hoping to get through the whole clinical trial program without any type of situation like this, but the fact that it's a Grade 2 is certainly encouraging. It was not severe. And I'll turn it to Suku, but I just want to highlight that this team really worked hard with the PIs in terms of monitoring and then managing. And this will get at your question, is how do you mitigate these type of things because they are expected to occur. Suku? Sukumar Nagendran: Yes, Sean and Salveen, thanks for the question. So as Sean highlighted, with AAV9 programs, you do see sensory neuropathy, so it's not uncommon. And it is usually easily managed with immunomodulatory agents if the clinical consequences need that kind of intervention. And as Sean highlighted, in our program, we've looked at this carefully, and the benefit significantly continues to -- the benefit is significantly more than any risk to this patient population. And there is very good data that in Rett syndrome patients that you do get peripheral neuropathies. So at times, the peripheral neuropathy and the clinical features of the disease itself can sometimes mask or be the main reason that you have the sensory neuropathy. And in this specific case, we worked very closely with the investigator and followed the institutional treatment protocols to work with them and to have appropriate immunomodulatory agents to treat the clinical presentation, and this patient recovered pretty quickly. There was substantial recovery post discharge from the hospital within 24 hours. So overall, we are quite pleased with the outcome for this patient. Operator: Your next question comes from the line of Tazeen Ahmad with Bank of America. Tazeen Ahmad: Maybe just a follow-up. Have you discussed these events with FDA? Have they provided any kind of feedback on any kind of change to monitoring requirements, or changes just in general to outpatient administration? Have you seen any similar neurological symptoms in other treated patients? Sean Nolan: Yes. Tazeen, thanks for the question. Let me give a little bit of context on this one, too, because I think it really does matter. Every situation is a little bit unique and in this particular instance, again, keep in mind, this is a Grade 2 moderate [Audio Gap] Grade 4 is considered life-threatening. Grade 5, obviously, is the worst outcome possible. So this is a mild to moderate type of a finding. It happened on the July 4 holiday. So the PI's out of town, sub-PI is managing things. A patient has a presentation and we very much supported this. They did exactly what Suku and his team have trained them to do, which is monitor closely and then treat very quickly. And so, as a result of that, the policy at the hospital was an overnight administration and monitoring, and that's what led to this being deemed a serious adverse event. Suku, you want to comment on that? Sukumar Nagendran: Yes. I was also going to address Tazeen's question about the FDA. So we did send this case report into the FDA, and so it has been disclosed to them. At this point, they have not had any questions. We've also disclosed this to the IDMC, and they felt it was part of the usual process of AAV9 therapy, and they raised no concerns either, and did not suggest anything different from what we have done up to now. Sean Nolan: Right. So the reason I was giving you the background, Tazeen, is to give you the context that I think had there not been some of these circumstances that I mentioned, very likely we would not even be talking about this. So it was a unique set of circumstances that contributed, which is why, as Suku mentioned, we feel very comfortable in our ability to manage this going forward. It's not unexpected in the disease or with AAV9, and obviously the IDMC felt that way. And it's been several weeks since we have corresponded with the FDA and again, nothing from them, which we frankly wouldn't expect anyway. Hope that helps. Operator: Our next question comes from the line of Maury Raycroft with Jefferies. Maurice Raycroft: I was going to focus on just the seizure data that you are collecting. For Part A, wondering if EEG data were collected, and if so, are you seeing any objective changes in EEG activity that correspond with the higher level improvements in seizures that were reported at IRSF? And how will seizure activity be assessed more rigorously in the pivotal versus Part A? Are you going to have enough patients and baseline data to evaluate benefit on seizures and potentially include that in the label? Sukumar Nagendran: Maury, that's a very interesting and important question. So as you probably know, when it comes to Rett syndrome, 80% to 90% of Rett syndrome patients do have a history of seizures, especially once they are 3 to 4 years of age. That's when they first start showing features of different types of seizures, whether it's generalized tonic-clonic or partial complex absence, et cetera. We do have seizure data from the Part A data set that we are evaluating. Overall, as Dr. Elsa Rossignol also disclosed in her presentation, there appears to be an overall decrease in seizure frequency and severity, and maybe even in the combination of meds dose. We are evaluating that data further in depth, and we may disclose some of that data at a major medical meeting, hopefully either late this year or maybe early next year. In the Part B data set, there are EEG data at baseline that occur, the patient's medical history, the medication history, et cetera, that includes anticonvulsant medications that are used. There are EEGs being done as a part of the protocol, but it's not a primary or secondary endpoint. It's probably more going to be exploratory. So at this point, it will give us a signal potentially on hopefully the beneficial effects of TSHA-102 when it comes to seizure control as well. But all I can say at this point is stay tuned, and we will update you further as we get that information. One thing that's reassuring at this point in time as of today is, we don't see worsening of seizures, which is important as well. Operator: Our next question comes from the line of Chris Raymond with Raymond James. Unknown Analyst: This is Stanley on for Chris Raymond. Maybe just one more follow-up on the safety event. I know that this is related to AAV exposure, but do you think that there also could have been related to the intrathecal administration? And was there anything about the patient such as age, dose exposure, or any other risk factors that might have predisposed them to the event? Sean Nolan: I'll turn this over to Suku, but I can say at a high level, there was nothing relative to the administration that was noted by the PI. As you know, this is done very commonly. Again, the age of the patient really had no bearing on this circumstance. And things essentially can happen, and I think that's what we have here. So I don't believe there's any read-through, but Suku, you should certainly comment on this. Sukumar Nagendran: Yes, Sean, I agree that I don't think the lumbar puncture procedure itself puts the patient at high risk for this kind of incident. With AAV9, as we said earlier, you do sometimes see peripheral sensory neuropathies develop, and that could be one of the reasons that this occurred. But also, an important point we made earlier was that Rett syndrome patients do have their own features of peripheral and polyneuropathies, and that also develops over time. So sometimes could they have both concurred at the same time? Maybe, but we will not know at this point in time. But the most important thing is the patient responded and is doing much better now, and that obviously assures us as well on the overall safety profile for the product. Operator: Our next question comes from the line of Jack Allen with Baird. Jack Allen: Congrats on the progress made over the course of the quarter. Two quick ones from our end. I was hoping you could add some more color on when the dosing of ASPIRE completed. I think you guys were targeting July, and I'm just curious if you have any more precision about when in July that may have completed. And then as it relates to the more recent disclosure around the sensory neuropathy, it's great to hear the patient is on the mend. Any more color you can provide on the immunomodulatory agents that were given to that patient and the time course to recovery would be very helpful as well. Sean Nolan: Yes, Jack, thanks for the questions. I think we haven't been super precise in terms of dates on the dosing just historically. I would say it's been several weeks since the last ASPIRE patient was dosed. This event that we're talking about here happened 6 weeks post dosing. So all the people in the pivotal trial are beyond that, obviously. So that's probably the most clarity that we can provide on that. I don't know, Suku, if there's anything more to add? Sukumar Nagendran: Well, what I would add, Sean, is that, the patient started recovering pretty quickly after the treatment was given. And we haven't got into details around what the specific therapies were or what the details were behind the patient, because that could be disclosing the patient's potential protected health information as well. So we are not going to get into that at this point in time. Sean Nolan: But you did mention, Suku, that the way to manage these types of things is with immunosuppression or immunomodulatory agents. Sukumar Nagendran: Correct. Because that's what's relatively standard. Sean Nolan: Yes, it's pretty forward. Very standard. Hope that helps, Jack. Operator: Our next question comes from the line of Yanan Zhu with Wells Fargo. Yanan Zhu: Just on the safety event, was wondering, is it the expectation that patients who might have peripheral neuropathy could have a full recovery upon immunomodulatory treatment? And then also, I was wondering the role of prophylactic immunosuppression and how that might have -- could have impacted on this kind of event. I believe patients do have prophylactic steroid, although whether they had -- I wasn't sure whether steroid was also used prophylactically. Sukumar Nagendran: So, Yanan, you had multiple questions in your question there, so let me try to answer all of them in a very simple manner. So the prophylactic immunomodulation given for protocol, overall, I think, does have very positive impact on the occurrence of these peripheral neuropathies post-AAV9 gene therapy. So that is why they're not overwhelmingly seen, but they are seen common. Okay? So if you know what I mean. Second is the peripheral neuropathies that may or may related to AAV9 gene therapy, regardless of route of administration. If the recovery to the immunomodulatory intervention is rapid, we observe that the patient is going to get much better quicker over time. So that is a positive signal clinically. So hopefully that's what we see eventually with this patient. And what was the other -- there was another question. You had 3 questions. Did I answer your question, Yanan? Yanan Zhu: Sorry, I didn't quite hear whether prophylactic treatment could play a role in preventing this or... Sukumar Nagendran: Yes. Prophylactic treatment will play a role, not in preventing, but in reducing the incidence. Does that make sense? Yanan Zhu: Okay. Yes. Sukumar Nagendran: Yes. So what I'm saying is, if you didn't give any prophylactic treatment, you might see a few more cases, but it won't be overwhelming. But prophylactic treatment reduces the incidence. Operator: Our next question comes from the line of Gil Blum with Needham. Unknown Analyst: This is Jonathan on for Gil. I just had a quick question, if you guys could provide any color around the over-enrollment, it looks like for your ASPIRE and pivotal trials. It seems like you guys got an extra patient in the ASPIRE and 2 in the pivotal. Sean Nolan: Yes, Jonathan. The rationale behind that was because we didn't want to leave any patient behind. So we made a commitment that if you went into screening and you screened into the study, that we would treat you. And so, one of the reasons that you have to consider doing that is that, if you do get a screen fail and you don't have more patients than you're planning for in the process of being screened, you could end up delaying your enrollment. So we made a conscious decision to work that way as a clinical operations organization, and we work very closely with the PIs and the potential caregivers so that they understood that and they understood the commitment that we made. So that's why there is a few more patients in the REVEAL pivotal and one additional patient in the ASPIRE trial. Operator: Our next question comes from the line of Angela Qian with Canaccord Genuity. Angela Qian: This is Angela on for Whitney. First question is on the safety. You guys mentioned that Rett patients typically get peripheral neuropathy. Does that present normally more like acute events, or is that more chronic when it happens in the population? And then separately, have you guys talked about potential sales size for us and what the commercial organization would need to look like to support a launch? Sean Nolan: Just on that last question, did you ask about the size of the commercial organization? Angela Qian: Yes, just like have you said anything about how many salespeople you might need to support the launch? Sukumar Nagendran: How many salespeople? Sean Nolan: Oh, no. You know what, I'll take that part first. I would say more to come on that, Angela. It's a relatively discreet SG&A, and I think what you're going to see is a combination of a relatively small amount of "sales representatives." You're going to have a group of people that are very focused on working to secure kind of reimbursement for the families, and that's going to be a big part of what we do. Patient services is going to be another group that's instrumental in working with the families to make sure that everything gets navigated from the time the prescription gets written to them, getting to the institution and treated to them working with the insurance companies to make sure that reimbursement occurs. So we're going to put the resources in play to make sure that it's the most optimal situation and journey for the families going through this. So there'll definitely be more to come later this year, beginning of next year, as we further refine our details around the go-to-market strategy and what that organization looks like. We've done a lot of work thus far, and at this point, it's, again, doing more market research and work to make sure we really understand the patient journey and flow. And we have a good idea right now. I would say we're 80% of what we -- I think we have 80% line of sight of what this is going to look like, but I think before we give more detail, I'd like to get additional information, and then we can give you a very fulsome report on that. Sukumar Nagendran: And you had another question on the neuropathy. Patients with Rett syndrome do develop peripheral sensory and at times, a mixed neuropathy, and it becomes chronic over time. So if your question is it sudden acute, and does it resolve on its own? Usually not. It's more of a chronic process. Operator: Our next question comes from the line of Evan Seigerman with BMO Capital Markets. Evan Seigerman: I wanted to touch on some of the manufacturing and CMC work that you are working on. Beyond the completion of the PPQ runs, what CMC activities remain kind of on the critical path to the BLA? Are we talking assay validation, process validation reports, shipping hold time validation, or other kind of components of that? And just as a follow-up, when you say the FDA has agreed with the comparability approach, kind of can you just drill into what that actually means in terms of the process in getting to commercial product? Sean Nolan: Yes, great question. I would say, in terms of -- if we start with the comparability, the first time we hit a line with the FDA on comparability was when we compared the clinical lot, so that was the lot in Part A, with our first commercial lot, which is the part in Part B, right? And so it was kind of a 1-to-1 comparison. And we went through all the different analytics and product characterization parameters with the FDA [Audio Gap] analytically comparable. Subsequent to that, we've run more batches of the commercial process, and they've continued, and I think we disclosed this a few quarters ago, that they continue to deem us analytically comparable to the clinical lot. So the next step is that, when we complete the PPQ runs, if those 2 are comparable from an analytical perspective, which we fully expect, that then allows us to utilize the Part A data, both in terms of efficacy and safety to support the regulatory submission. So we're in a really good spot there. You asked about assay validations and things of that nature, we're in a really good spot there with the FDA. So really what's on the critical path is us completing the PPQ runs and then having that discussion with the FDA after we submit all the data around what the comparability looks like. So I would say in a nutshell, we're very pleased where we are on the CMC side, and at this point in time, CMC is not a critical path item for us. Operator: Our next question comes from the line of [ Joshua Woodman ] with Citizens. Unknown Analyst: Congrats on the update. Maybe just going back to IRSF, you presented a really great poster outlining the establishment of the [ RSDMA ], the development milestone assessment. I was hoping you guys could just reiterate the key points there and highlight how this provides confidence in the reliability of essential raters and confidence in the validity and interpretability of the data from a regulator's perspective. Sean Nolan: We can tag team this, but I think it starts with the fact that we're creating, via the milestone strategy, a novel pathway for approval in Rett syndrome, right? I mean, to date, the only thing that has been approved has been approved based on CGI and RSBQ. And we knew that for a gene therapy, that was not going to be sufficient to garner capturing the value we think would be commensurate with the product. The payers would not have paid with that as your 2 endpoints, essentially. So we struck out on an endeavor to figure out what would be a clinically meaningful, very robust endpoint that's unequivocal that demonstrated the value of the product. And fortunately for us, we found the milestone plateau and then began to work on what's the construct of the actual tool that we'll use as the instrument to capture this data. And so, what we were able to do with the DMA is do exactly that. And so, it's a very systematized way to go through the assessment of the milestone. So keep in mind, there's 28 milestones, so you're going to want to put in place a process that's very systematic and very rigorous. So as an example, the sequence of the milestones is tested the same way every time. Any implements used in the study are consistent from baseline throughout the study, so it's very easy to, again, measure what you're seeing there. The angles of the cameras, as an example, is something that was tested. The manuals for the training. All of this took a lot of time. So it took 18 months from the concept to us being able to lock it down with the FDA, and fortunately for us, we ran a pilot in the background. We haven't talked too much about it, but we call it the [indiscernible] trial. And so, we were able to do the DMA in an nontreated population that was also, for the most part, sites in the clinical trial. So you knew like that was going to be a good index against then the ultimate final version of this, and that was also part of the submission that we made to the FDA. And that's how when we say that it is psychometrically validated, that pilot helped us validate that. We shared all that with the FDA, and that's what got them comfortable around taking this approach in an open label study, was how rigorous you're going to be able to collect that data and ensure that you had a clear baseline. So, I mean, we can go chapter and verse deeper on that, but at a very high level, that's what happened, and it took a lot of hard work from the team, and it took a lot of time. It wasn't something you could just jump into, and it was something the FDA was very concerned around, was the rigor and the systemization of that data collection. I don't know, Suku, if there is any more you might want to add? Sukumar Nagendran: No. All I would add, Sean, is the process and rigor of the collection and validation of the data set for the DMA was what was done in that study, and that was what was disclosed in the poster. And interestingly, there was an FDA representative at the IRSF meeting who actually presented to the audience and talked about the need for this kind of rigor, and also made a point that just because a patient population being studied is potentially highly variable, that doesn't -- cannot be used as an excuse for a poorly designed trial for approval of a product. It was a very interesting discussion that was raised. So this is a review of what also may be more relevant space with a currently approved product as well. So it was pretty timely, our data disclosure as well as the other presentations that occurred at IRSF. Operator: And I'm showing no further questions. So with that, I'll hand the call back over to Chairman and CEO, Sean Nolan, for any closing remarks. Sean Nolan: We appreciate everyone taking the time to hear our update, and we look forward to speaking with everyone in the future. Have a good night. Take care. Operator: Ladies and gentlemen, thank you for participating. This does conclude today's program, and you may now disconnect. Before you buy stock in Taysha Gene Therapies, consider this: The Motley Fool Stock Advisor analyst team just identified what they believe are the 10 best stocks for investors to buy now… and Taysha Gene Therapies wasn’t one of them. The 10 stocks that made the cut could produce monster returns in the coming years. 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As with all our articles, The Motley Fool does not assume any responsibility for your use of this content, and we strongly encourage you to do your own research, including listening to the call yourself and reading the company's SEC filings. Please see our Terms and Conditions for additional details, including our Obligatory Capitalized Disclaimers of Liability. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy. Taysha Gene Therapies (TSHA) Q2 2026 Earnings Call was originally published by The Motley Fool

This article first appeared on GuruFocus. R&D Expenses: $38.6 million for Q2 2026, up from $20.1 million in Q2 2025. G&A Expenses: $12.1 million for Q2 2026, up from $8.6 million in Q2 2025. Net Loss: $46.6 million, or $0.13 per share, for Q2 2026, compared to a net loss of $26.9 million, or $0.09 per share, in Q2 2025. Cash Position: $455.4 million in cash and cash equivalents as of June 30, 2026. Cash Runway: Expected to support planned operations into the second half of 2028. Warning! GuruFocus has detected 5 Warning Sign with TSHA. Is TSHA fairly valued? Test your thesis with our free DCF calculator. Release Date: August 11, 2026 For the complete transcript of the earnings call, please refer to the full earnings call transcript. Completed dosing in both the REVEAL Pivotal and ASPIRE trials, with 17 and 4 patients respectively, supporting a broad label for Rett syndrome. Longer-term Part A data showed a 100% response rate at 12 months, far exceeding the FDA-aligned 33% efficacy threshold, with no plateau effect observed. Favorable safety profile across 33 treated patients, with no severe treatment-related serious adverse events or dose-limiting toxicities as of August 2026. Expanded partnership with Catalent for commercial manufacturing, securing long-term capacity at an FDA-licensed facility with BLA-enabling PPQ activities underway. Strengthened balance sheet with $455.4 million in cash, extending runway into the second half of 2028 and through potential BLA approval. Payer research indicated strong support for Taysha-102's value proposition, driven by its transformative potential and convenient intrathecal administration. Reported a grade 2 treatment-related serious adverse event of peripheral sensory neuropathy in a REVEAL Pivotal patient, requiring overnight hospitalization. R&D expenses increased significantly to $38.6 million in Q2 2026, up from $20.1 million in Q2 2025, due to manufacturing and clinical costs. Net loss widened to $46.6 million in Q2 2026, compared to $26.9 million in Q2 2025, reflecting higher operating expenses. The six-month interim analysis from the REVEAL Pivotal trial is not expected until the first half of 2027, leaving regulatory uncertainty for an extended period. The company faces potential challenges in managing AAV9-associated peripheral neuropathy risks, which may require ongoing monitoring and immunomodulatory interventions. Commercial launch readiness is still in early stages, with limited details on sales force size and go-to-market strategy, creating execution risk. Q: Can you help us further understand the grade 2 SAE? You noted that this is an expected AAV-associated risk, but how do you mitigate this risk on the forward and how frequent are these type of events for gene therapies that leverage AAV9? A: Sean Nolan (CEO): This is a known effect of AAV9, and peripheral neuropathies are also common in the Rett syndrome population itself, with over 50% of patients experiencing them as part of the disease course. In this case, it was a moderate grade 2 event, and the benefit-risk profile tilts heavily toward benefit. Sukumar Nagendran (President, Head of R&D): Sensory neuropathy is not uncommon with AAV9 programs and is usually easily managed with immunomodulatory agents. We worked closely with the investigator and followed institutional protocols. The patient recovered quickly with substantial recovery within 24 hours of discharge. The IDMC reviewed the case and felt it was part of the usual process of AAV9 therapy with no concerns. Q: Have you discussed this event with FDA? Have they provided any kind of feedback on any kind of change to monitoring requirements? Or changes just in general to outpatient administration? And have you seen any similar neurological symptoms in other treated patients? A: Sean Nolan (CEO): This was a grade 2 moderate event that occurred over the July 4th holiday when the PI was out of town. The patient was admitted overnight for observation per hospital policy, which led to the technical SAE classification. Had it not been for these unique circumstances, we likely wouldn't be discussing this. Sukumar Nagendran (President, Head of R&D): We did send this case report to the FDA, and they have not had any questions. We also disclosed this to the IDMC, who felt it was part of the usual process of AAV9 therapy and did not suggest any changes to our approach. Q: I was hoping you could provide some more color on when the dosing of the Aspire completed. And then as it relates to the more recent disclosure around the sensory neuropathy, any more color you could provide on the immunomodulatory agents that were given to that patient and the time course of recovery would be very helpful as well. A: Sean Nolan (CEO): We haven't been super precise on dosing dates historically, but it's been several weeks since the last ASPIRE patient was dosed. The safety event happened six weeks post-dosing. Sukumar Nagendran (President, Head of R&D): The patient started recovering pretty quickly after treatment was given. We won't get into specific therapies or patient details as that could be protected health information. Sean Nolan (CEO): The standard way to manage these types of events is with immunosuppression or immunomodulatory agents. Q: Just on the safety event, I was wondering, is it the expectation that patients who might have peripheral neuropathy could have full recovery upon immunomodulatory treatment? And then also was wondering the role of prophylactic immunosuppression and how that might have impacted this kind of event. A: Sukumar Nagendran (President, Head of R&D): Prophylactic immunomodulation given per protocol has a very positive impact on the occurrence of these peripheral neuropathies post-gene therapy, reducing the incidence. If the recovery to immunomodulatory intervention is rapid, the patient is going to get much better quicker over time, which is a positive clinical signal. Prophylactic treatment plays a role not in preventing, but in reducing the incidence of these events. Q: I wanted to touch on some of the manufacturing and CMC work that you're working on. Beyond the completion of the PPQ run, what CMC activities remain on the critical path of the BLA? And when you say the FDA has agreed with the comparability approach, can you just build into what that actually means in terms of the process and getting to commercial products? A: Sean Nolan (CEO): The first comparability discussion with the FDA was comparing the clinical lot from Part A with our first commercial lot from Part B, which was deemed analytically comparable. Subsequent batches have continued to be deemed comparable. When we complete the PPQ runs, if those are comparable analytically, which we fully expect, that allows us to utilize the Part A data for both efficacy and safety to support the regulatory submission. We're in a really good spot with assay validations. What's on the critical path is completing the PPQ runs and then having the comparability discussion with the FDA. CMC is no longer a critical path item for us. Q: For Part A, wondering if EEG data were collected and if so, are you seeing any objective changes in EEG activity that correspond with the higher level improvements in seizures that were reported at IRSF? And how will seizure activity be assessed more rigorously in the pivotal versus Part A? A: Sukumar Nagendran (President, Head of R&D): 80% to 90% of Rett syndrome patients have a history of seizures. We do have seizure data from the Part A dataset that we are evaluating. As Dr. Elsa Rossignol disclosed in her presentation, there appears to be an overall decrease in seizure frequency and severity, and possibly in the combination of medication doses. We may disclose more data at a major medical meeting late this year or early next year. In the Part B dataset, there are EEGs being done as part of the protocol, but it's exploratory, not a primary or secondary endpoint. Importantly, as of today, we don't see worsening of seizures. Q: Maybe just going back to IRSF, you presented a really great poster outlining the establishment of the RFS-DMA, the Developmental Milestone Assessment. I was hoping you guys could just reiterate the key points there and highlight how this provides confidence in the reliability of the central raters and confidence in the validity and interpretability of the data from a regulator's perspective. A: Sean Nolan (CEO): We're creating a novel pathway for approval in Rett syndrome. The only approved product was based on CGI and RSBQ, which we knew wouldn't capture the value commensurate with a gene therapy. We developed the DMA as a very systematized way to assess 28 milestones. The sequence of milestones is tested the same way every time, implements are consistent from baseline, camera angles were tested, and training manuals were developed. It took 18 months from concept to locking it down with the FDA. We ran a pilot called the RESUME trial in a non-treated population to validate the DMA psychometrically, which we shared with the FDA. Sukumar Nagendran (President, Head of R&D): The process and rigor of collection and validation was disclosed in the poster. Interestingly, an FDA representative at the IRSF meeting For the complete transcript of the earnings call, please refer to the full earnings call transcript.

Interested in Taysha Gene Therapies, Inc.? Here are five stocks we like better. Taysha completed dosing in its over-enrolled REVEAL pivotal trial and ASPIRE study for TSHA-102 in Rett syndrome. A six-month interim analysis could support a BLA filing and potentially accelerate submission by at least two quarters, with data and FDA feedback expected in the first half of 2027. Long-term Part A data showed all 12 patients were developmental-milestone responders at 12 months, well above the FDA-aligned 33% efficacy threshold. The therapy was generally well tolerated, although one patient experienced a treatment-related Grade 2 peripheral sensory neuropathy that substantially improved. Taysha is advancing commercial manufacturing and launch preparations while its cash position of $455.4 million is expected to fund operations into the second half of 2028. However, higher clinical, manufacturing and launch-readiness spending widened the second-quarter net loss to $46.6 million from $26.9 million a year earlier. Neurogene Stock Plummets 44%: Is All Hope Lost for This Biotech?" Taysha Gene Therapies (NASDAQ:TSHA) said it completed dosing in its REVEAL pivotal trial and ASPIRE trial for TSHA-102, its gene therapy candidate for Rett syndrome, while preparing for a potential biologics license application submission. Chief Executive Officer Sean Nolan said the company dosed 17 patients in the over-enrolled REVEAL pivotal trial and four patients ages 2 to under 4 in the ASPIRE study. The REVEAL trial enrolled pediatric, adolescent and adult patients, which Nolan said reflects the broader Rett syndrome population. → SoundHound AI Sends a Loud Signal After Its Q2 Earnings Beat 3 Small-Cap Stocks For Your Fall Shopping List The company plans to conduct a six-month interim analysis after all 17 REVEAL pivotal-trial patients complete six months of follow-up. Taysha said the analysis could form the basis of a planned BLA submission and potentially accelerate its filing timeline by at least two quarters compared with waiting for 12-month data. The company expects to report top-line interim data and FDA feedback on its BLA pathway in the first half of 2027. Sukumar Nagendran, Taysha’s president and head of research and development, discussed longer-term data from Part A of the REVEAL Phase I/II trial presented at the International Rett Syndrome Foundation scientific meeting. As of a May 2026 data cutoff, all 12 treated patients had at least 12 months of follow-up. → 3 Dividend Champion Utilities for a Market That Can't Sit Still Using the FDA-aligned developmental milestone assessment criteria planned as the pivotal trial’s primary endpoint, Taysha reported that 75% of Part A patients were responders at three months, 83% were responders at six months and all 12 patients were responders by 12 months. The company said the FDA-aligned minimum efficacy threshold for the pivotal trial is a 33% response rate. Patients achieved 31 total developmental milestones, including 16 among six pediatric patients and 15 among six adolescent and adult patients, according to Nagendran. At 12 months and beyond, the company recorded 310 functional gains across communication, fine motor, gross motor and autonomic domains, averaging 26 gains per patient. → Is Wingstop's Growth Story Losing Steam? Taysha also presented a Rett syndrome natural-history analysis indicating that developmental progress plateaus after age 6 and that the chance of gaining or regaining a lost developmental milestone declines to less than 6.7%. Nagendran said the data support REVEAL’s minimum enrollment age of 6 and help distinguish observed trial gains from the disease’s expected natural history. The company additionally cited a methods study supporting the developmental milestone assessment as a psychometrically valid and FDA-supported endpoint for a single-arm interventional study. Taysha said both high- and low-dose TSHA-102 have been generally well tolerated. Across 33 patients treated in the REVEAL Phase I/II, pivotal and ASPIRE studies as of the August 2026 cutoff, the company reported no severe treatment-related serious adverse events or dose-limiting toxicities. However, one patient in the REVEAL pivotal trial experienced a treatment-related Grade 2 peripheral sensory neuropathy about six weeks after treatment in early July. The patient was admitted overnight under the treating institution’s policy, causing the event to be technically classified as a serious adverse event, Nolan said. The patient was discharged the next day and showed substantial recovery, according to the company. Nagendran said peripheral sensory neuropathy is a known risk associated with AAV9-based therapies and can be managed with immunomodulatory agents when clinically needed. He said Taysha reported the event to the FDA and its independent data monitoring committee, neither of which had raised concerns or recommended changes to the company’s approach as of the call. The company said prophylactic immunomodulation can reduce, but not necessarily prevent, the incidence of peripheral neuropathies after AAV9 gene therapy. Taysha said it has not observed worsening seizures in treated patients. Seizure-related data, including electroencephalogram information collected in the pivotal trial, are exploratory rather than primary or secondary endpoints. Taysha expanded its partnership with Catalent to include commercial manufacturing support for TSHA-102 if the therapy is approved. Manufacturing is planned at Catalent’s FDA-licensed gene therapy facility in Harmans, Maryland. Nolan said BLA-enabling process performance qualification activities are underway and remain on track for completion in the fourth quarter of 2026. During the question-and-answer session, Nolan said the company has discussed comparability between its clinical product lot and commercial manufacturing lots with the FDA. He said the agency has considered the lots analytically comparable to date, and that completing the process performance qualification runs is the remaining major manufacturing step ahead of a subsequent FDA discussion. The company also completed payer research that Nolan said found support for TSHA-102’s potential value proposition. According to Taysha, payers focused on the potential for durable functional gains, safety and efficacy. Nolan said payers viewed a one-time intrathecal administration as less invasive than some other direct-to-central-nervous-system delivery approaches and noted its potential use in outpatient settings. Taysha appointed Mike Johannesen as chief legal officer during the quarter. The company also said it plans to provide additional details on its prospective commercial organization and market-access strategy later in 2026 or early 2027. Research and development expense rose to $38.6 million in the second quarter from $20.1 million a year earlier, primarily due to BLA-enabling manufacturing work, higher clinical-trial costs and additional R&D headcount. General and administrative expense increased to $12.1 million from $8.6 million, driven by compensation, consulting, professional fees and launch-readiness initiatives. Net loss was $46.6 million, or $0.13 per share, compared with a net loss of $26.9 million, or $0.09 per share, in the prior-year quarter. Cash and cash equivalents totaled $455.4 million as of June 30, including proceeds from a $230 million June follow-on financing. Chief Financial Officer Kamran Alam said Taysha expects its cash resources to fund planned operating expenses and capital requirements into the second half of 2028. Taysha Gene Therapies, Inc (NASDAQ: TSHA) is a clinical-stage biotechnology company focused on developing gene therapies for rare monogenic diseases of the central nervous system. Using a proprietary adeno-associated viral (AAV) vector platform, the company engineers novel capsids and regulatory elements to optimize delivery and expression of therapeutic genes. Its pipeline features lead programs such as TSHA-102 for GM2 gangliosidoses (Tay–Sachs and Sandhoff diseases), TSHA-101 for GM1 gangliosidosis and TSHA-103 for aromatic l-amino acid decarboxylase (AADC) deficiency, alongside earlier-stage candidates targeting other life-threatening pediatric CNS disorders. Founded in 2019 and headquartered in Dallas, Texas, Taysha Gene Therapies completed its initial public offering in May 2021. This instant news alert was generated by narrative science technology and financial data from MarketBeat in order to provide readers with the fastest reporting and unbiased coverage. Please send any questions or comments about this story to [email protected]. The article "Taysha Gene Therapies Q2 Earnings Call Highlights" was originally published by MarketBeat. View MarketBeat's top stocks for August 2026.

Our analysts just identified a stock with the potential to be the next Nvidia. Tell us how you invest and we'll show you why it's our #1 pick. Tap here. Management completed dosing in the REVEAL pivotal and ASPIRE trials, positioning the company for a 6-month interim analysis that could accelerate the BLA submission timeline by at least two quarters. Performance attribution is driven by Part A data where 100% of patients became responders by 12 months, significantly exceeding the FDA-aligned 33% efficacy threshold established for the pivotal trial. The strategic focus on 'developmental milestones' as a primary endpoint is intended to provide a more robust, value-based narrative for payers compared to traditional subjective scales. Operational context includes a well-balanced distribution of ages across pediatric and adult patients, which management believes supports a broad label for the approximately 85% of Rett patients over age 10. The partnership with Catalent was expanded to secure long-term commercial manufacturing capacity at an FDA-licensed facility, mitigating future supply chain risks. Market research indicates strong payer support for the one-time intrathecal administration, which is viewed as less invasive and more scalable than other direct-to-CNS approaches. Top-line data from the REVEAL pivotal 6-month interim analysis and subsequent FDA feedback on the BLA pathway are expected in the first half of 2027. The company expects to complete BLA-enabling Process Performance Qualification (PPQ) manufacturing campaigns in the fourth quarter of 2026. Current cash resources of $455.4 million are projected to support operations into the second half of 2028, covering the period through potential BLA approval. Management assumes that demonstrating durable functional gains will be the primary determinant for securing favorable reimbursement and market access at launch. A single moderate Grade 2 treatment-related SAE of peripheral sensory neuropathy was reported; management noted this is an expected risk of AAV9 and the patient recovered rapidly. The Independent Data Monitoring Committee (IDMC) raised no concerns regarding the SAE, viewing it as consistent with the known safety profile of AAV9 therapies. Management highlighted that over 50% of Rett patients naturally experience peripheral neuropathies, which may complicate the attribution of certain neurological adverse events. The company successfully raised $230 million in gross proceeds through a June 2026 follow-on financing to strengthen the balance sheet ahead of commercialization. One stock. Nvidia-level potential. 30M+ investors trust Moby to find it first. Get the pick. Tap here. Payers favor the intrathecal route because it is less invasive and allows for outpatient administration, which offers attractive margins for providers. Reimbursement willingness is anchored to the 'transformative' nature of the milestone data rather than just incremental improvements. The risk is managed through standard immunomodulatory agents and prophylactic treatments, which reduce the incidence but do not entirely eliminate the risk. Management clarified that the 'serious' classification of the recent event was a technicality due to an overnight hospital stay for observation during a holiday weekend. The DMA was psychometrically validated through an 18-month process involving a pilot study in untreated patients to establish a rigorous baseline. The FDA emphasized that disease variability is not an excuse for poor trial design, supporting Taysha's highly systematized approach to capturing functional gains. The FDA has already deemed the commercial process analytically comparable to the clinical lot used in Part A. Successful PPQ runs will allow the company to use earlier clinical data to support the final regulatory submission package.

Completed dosing in the REVEAL pivotal (N=17) and ASPIRE (N=4) trials evaluating TSHA-102 for Rett syndrome; expect to report topline data from 6‑month interim analysis and FDA feedback on the BLA submission pathway in 1H 2027 TSHA-102 continues to be generally well tolerated with no severe treatment-related SAEs or DLTs across REVEAL Phase 1/2, pivotal and ASPIRE trials (N=33) as of the August 2026 data cutoff Longer-term REVEAL Part A data demonstrated broad, multi-domain functional gains that deepened through ≥12 months post-TSHA-102, with consistent responses across ages and disease severity Advanced TSHA-102 commercial readiness activities, including market access planning initiatives and expansion of strategic partnership with Catalent to support future commercial manufacturing Completed $230 million follow-on offering, extending cash runway into 2H 2028 and through potential BLA approval of TSHA-102 Conference call and webcast today at 4:30 PM ET DALLAS, Aug. 11, 2026 (GLOBE NEWSWIRE) -- Taysha Gene Therapies, Inc. (Nasdaq: TSHA) (Taysha or the Company), a clinical-stage biotechnology company focused on advancing adeno-associated virus (AAV)-based gene therapies for severe monogenic diseases of the central nervous system (CNS), today reported financial results for the second quarter ended June 30, 2026, and provided a corporate update. “During the second quarter, we continued to execute against our clinical development strategy for TSHA-102 while advancing key commercial and manufacturing readiness initiatives in support of a potential BLA submission,” said Sean P. Nolan, Chairman and Chief Executive Officer of Taysha. “The completion of dosing in our REVEAL pivotal and ASPIRE trials, as well as positive longer-term follow-up data from our REVEAL Phase 1/2 trials continues to strengthen our conviction in TSHA-102 as a potentially transformative therapy for this devastating disease with high unmet need. In addition, the favorable safety profile observed to date across a broad and diverse patient population supports TSHA-102’s potential to safely deliver durable, meaningful functional benefits.” Mr. Nolan continued, “We are working diligently to advance our commercial readiness activities to support the potential launch of TSHA-102, if approved. Our ongoing market and payer research continues to inform our market access strategy and reinforces TSHA-102’s significant value proposition and reimbursement potential. We have also expanded our partnership with Catalent, establishing a robust commercial supply framework to support the potential launch of TSHA-102 and strong demand we expect following potential FDA approval. Looking ahead, with a strengthened balance sheet, we remain focused on executing our BLA-enabling activities and anticipate reporting topline data from the REVEAL pivotal trial six-month interim analysis and FDA feedback on the BLA submission pathway in the first half of 2027.” Recent Corporate and TSHA-102 Program Highlights Completed Dosing in the REVEAL Pivotal Trial. Taysha completed dosing in the overenrolled REVEAL pivotal trial, with a total of 17 patients in the developmental plateau population of Rett syndrome dosed with TSHA-102. The REVEAL pivotal trial is a single-arm, open-label trial evaluating a single intrathecal (IT) administration of high dose TSHA-102 (1x1015 total vector genomes (vg)) in females with Rett syndrome between the ages of 6 to <22 years. The primary endpoint will assess response rate, defined as the percentage of patients who gain or regain ≥one of the 28 natural history-defined developmental milestones, with each patient serving as their own control. Completed Dosing in the ASPIRE Trial. Taysha completed dosing in the overenrolled ASPIRE trial, with a total of four patients with Rett syndrome, aged 2 to 15 total vg), scaled to account for the lower brain volume in 2 to TSHA-102 Continues to be Generally Well-Tolerated. High dose (1x1015 total vg) and low dose (5.7x1014 total vg) TSHA-102 continue to be generally well tolerated with no severe treatment-related serious adverse events (SAEs) or dose limiting toxicities (DLTs) in all patients treated in the REVEAL Phase 1/2, REVEAL pivotal and ASPIRE trials (N=33) as of the August 2026 data cutoff. Presented Data Supporting TSHA-102 Clinical Program at IRSF. Four poster presentations were delivered at the 2026 International Rett Syndrome Foundation (IRSF) Rett Syndrome Scientific Meeting. The posters, which are available on the Company’s website, highlighted: Advanced Commercial Readiness Activities to Support Potential Launch of TSHA-102. Strengthened Legal and Compliance Leadership through the Appointment of Mike Johannesen as Chief Legal Officer in June 2026. Mr. Johannesen brings over three decades of experience in corporate law, governance, compliance and strategic transactions across the biopharmaceutical and healthcare industries, having held executive roles at Advanced Medicine Partners, Jaguar Gene Therapy and AveXis. Completed Public Follow-on Offering with Total Gross Proceeds of $230 Million. Proceeds included full exercise of the underwriters’ option to purchase additional shares; anticipated cash runway extends into the second half of 2028 and through potential BLA approval of TSHA-102. Anticipated Milestones Completion of BLA-enabling Process Performance Qualification (PPQ) campaign for TSHA-102 is expected in the fourth quarter of 2026 Topline data from REVEAL pivotal trial 6-month interim analysis and FDA feedback on the BLA submission pathway for TSHA-102 is expected in the first half of 2027 Second Quarter 2026 Financial Highlights Research and Development Expenses: Research and development expenses were $38.6 million for the three months ended June 30, 2026, compared to $20.1 million for the three months ended June 30, 2025. The $18.5 million increase was primarily driven by BLA-enabling PPQ manufacturing initiatives performed during the three months ended June 30, 2026, and higher clinical expenses from the REVEAL and ASPIRE trials. Compensation expenses, including non-cash stock-based compensation, also increased as a result of additional research and development headcount. General and Administrative Expenses: General and administrative expenses were $12.1 million for the three months ended June 30, 2026, compared to $8.6 million for the three months ended June 30, 2025. The increase of $3.5 million was primarily due to higher compensation expenses, including non-cash stock-based compensation expense, and increases in consulting and professional fees, including commercial launch-readiness initiatives. Net Loss: Net loss for the three months ended June 30, 2026, was $46.6 million, or $0.13 per share, compared to a net loss of $26.9 million, or $0.09 per share, for the three months ended June 30, 2025. Cash and Cash Equivalents: As of June 30, 2026, Taysha had $455.4 million in cash and cash equivalents. This reflects the gross proceeds of $230.0 million from the June 2026 follow-on financing, including full exercise of the underwriters’ option to purchase additional shares. The Company expects that its current cash resources will support planned operating expenses and capital requirements into the second half of 2028. Conference Call and Webcast InformationTaysha management will host a live conference call and webcast today at 4:30 p.m. ET to review its financial and operating results and provide a corporate update. Participants may access the live webcast of the conference call by visiting Taysha’s website. About TSHA-102TSHA-102 is a self-complementary intrathecally delivered AAV9 investigational gene transfer therapy in clinical evaluation for Rett syndrome. Designed as a one-time treatment, TSHA-102 aims to address the genetic root cause of the disease by delivering a functional form of MECP2 to cells in the CNS. TSHA-102 utilizes a novel miRNA-Responsive Auto-Regulatory Element (miRARE) technology designed to mediate levels of MECP2 in the CNS on a cell-by-cell basis without risk of overexpression. TSHA-102 has received Breakthrough Therapy, Regenerative Medicine Advanced Therapy, Fast Track and Orphan Drug and Rare Pediatric Disease designations from the FDA, Orphan Drug designation from the European Commission and Innovative Licensing and Access Pathway designation from the Medicines and Healthcare products Regulatory Agency. About Rett SyndromeRett syndrome is a rare neurodevelopmental disorder caused by mutations in the X-linked MECP2 gene encoding methyl CpG-binding protein 2 (MeCP2), which is essential for regulating neuronal and synaptic function in the brain. The disorder is characterized by loss of communication and hand function, slowing and/or regression of development, motor and respiratory impairment, seizures, intellectual disabilities and shortened life expectancy. Rett syndrome progression is divided into four key stages, beginning with early onset stagnation at 6 to 18 months of age followed by rapid regression, plateau and late motor deterioration. Rett syndrome primarily occurs in females and is one of the most common genetic causes of severe intellectual disability. Currently, there are no approved disease-modifying therapies that treat the genetic root cause of the disease. Rett syndrome caused by a pathogenic/likely pathogenic MECP2 mutation is estimated to affect between 15,000 and 20,000 patients in the U.S., EU, and U.K. About Taysha Gene TherapiesTaysha Gene Therapies (Nasdaq: TSHA) is a clinical-stage biotechnology company focused on advancing adeno-associated virus (AAV)-based gene therapies for severe monogenic diseases of the central nervous system. Its lead clinical program TSHA-102 is in development for Rett syndrome, a rare neurodevelopmental disorder with no approved disease-modifying therapies that address the genetic root cause of the disease. With a singular focus on developing transformative medicines, Taysha aims to address severe unmet medical needs and dramatically improve the lives of patients and their caregivers. The Company’s management team has proven experience in gene therapy development and commercialization. Taysha leverages this experience, its manufacturing process and a clinically and commercially proven AAV9 capsid in an effort to rapidly translate treatments from bench to bedside. For more information, please visit www.tayshagtx.com. Forward-Looking StatementsThis press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as “anticipates,” “believes,” “expects,” “intends,” “projects,” “plans,” and “future” or similar expressions are intended to identify forward-looking statements. Forward-looking statements include, but are not limited to, statements concerning the potential of TSHA-102 and Taysha’s other product candidates to positively impact quality of life and alter the course of disease in the patients Taysha seeks to treat, Taysha’s research, development, regulatory and manufacturing plans for its product candidates, communications with the FDA, including with respect to the BLA for TSHA-102, the potential for Taysha’s product candidates to receive regulatory approval from the FDA or equivalent foreign regulatory agencies, and whether, if approved, these product candidates will be successfully distributed and marketed and the potential market opportunity for Taysha’s product candidates, Taysha’s commercial readiness activities, and the ability of Taysha’s current cash resources to support planned operating expenses into the second half of 2028. Forward-looking statements are based on management’s current expectations and are subject to various risks and uncertainties that could cause actual results to differ materially and adversely from those expressed or implied by such forward-looking statements. Accordingly, these forward-looking statements do not constitute guarantees of future performance, and you are cautioned not to place undue reliance on these forward-looking statements. Risks regarding Taysha’s business are described in detail in Taysha’s Securities and Exchange Commission (“SEC”) filings, including in our Annual Report on Form 10-K for the full-year ended December 31, 2025, which are available on the SEC’s website at www.sec.gov. Additional information will be made available in other filings that Taysha makes from time to time with the SEC. These forward-looking statements speak only as of the date hereof, and Taysha disclaims any obligation to update these statements except as may be required by law. Company Contact:Hayleigh Collins Vice President, Corporate Communications and Investor RelationsTaysha Gene Therapies, [email protected] Media Contact:[email protected]

Image source: The Motley Fool. Wednesday, May 6, 2026 at 8:30 a.m. ET Chief Executive Officer — Sean Nolan President and Head of R&D — Sukumar Nagendran Chief Financial Officer — Kamran Alam Need a quote from a Motley Fool analyst? Email [email protected] Sean Nolan, Taysha's Chief Executive Officer; Sukumar Nagendran, President and Head of R&D; and Kamran Alam, Chief Financial Officer. We will hold a question-and-answer session following our prepared remarks. On today's call, we will be making forward-looking statements, including statements concerning the potential of TSHA-102, including the reproducibility and durability of any favorable results initially seen in patients dosed to date in clinical trials, including with respect to functional milestones to positively impact quality of life and alter the course of disease in the patients we seek to treat, our research, development and regulatory plans for our product candidates, including the timing of initiating additional trials, reporting data from our clinical trials, making regulatory submissions, timing or outcomes of communications with the FDA and the regulatory pathway for TSHA-102, the potential for the product candidate to receive regulatory approval from the FDA or equivalent foreign regulatory agencies; our ability to realize benefits of breakthrough therapy designation for TSHA-102, our ability to drive long-term value for stockholders and the market opportunity for our programs. This call may also contain forward-looking statements relating to Taysha's growth, forecasted cash runway and future operating results, discovery and development of product candidates, strategic alliances and intellectual property as well as matters that are not historical facts or information. Various risks may cause Taysha's actual results to differ materially from those stated or implied in such forward-looking statements. For a list and description of the risks and uncertainties that we face, please see the reports that we have filed with the SEC, including in our annual report on Form 10-K for the full year ended December 31, 2025, that we filed on March 19, 2026, and our quarterly report on Form 10-Q for the quarter ended March 31, 2026, that we filed today. This conference call contains time-sensitive information that's accurate only as of the date of this live broadcast, May 6, 2026. Taysha undertakes no obligation to revise or update any forward-looking statements to reflect events or circumstances after the date of this conference call, except as may be required by applicable securities laws. With that, I would now like to turn the call over to our CEO, Sean Nolan. Sean Nolan: Thank you, Hayleigh, and welcome, everyone, to our first quarter 2026 financial results and corporate update conference call. On today's call, I will begin with an update on our recent regulatory, clinical and commercial readiness activities. Dr. Suku Nagendran, President and Head of R&D, will outline recently published preclinical data that continue to validate our novel TSHA-102 construct design and minimally invasive intrathecal route of administration. Kamran Alam, our Chief Financial Officer, will follow up with a financial update, and I will provide closing remarks and open the call for questions. We entered 2026 focused on a disciplined execution across our regulatory, clinical and pre-commercialization activities for TSHA-102 with the goal of delivering a potentially transformative therapy to a broad population of patients with Rett syndrome who continue to face high unmet need. Over the past several months, we have continued to advance our TSHA-102 clinical development program and made progress towards key clinical milestones anticipated in the second quarter of 2026. On the regulatory front, we recently held an initial breakthrough therapy Type B multidisciplinary meeting with the FDA. During the meeting, we reaffirmed alignment on the planned pathway toward a BLA submission for TSHA-102, covering the pivotal trial design, endpoints and BLA submission scenarios, including the potential to submit for approval based on a 6-month interim analysis from the REVEAL pivotal trial. We believe our consistent constructive dialogue with the FDA continues to support our streamlined path toward a potentially expedited BLA submission. Additionally, in the first quarter of 2026, we held a Type C meeting with the FDA, where the FDA endorsed our proposed Process Performance Qualification or PPQ campaign strategy in support of our planned BLA submission. I am pleased to share that we initiated the BLA-enabling PPQ campaign using our TSHA-102 commercial manufacturing process in April, and we expect to complete execution by the fourth quarter of this year. As a result, we are confident that our CMC activities are on track to support our BLA submission in step with the pivotal data readout. As a reminder, the FDA previously agreed that TSHA-102 material produced from the clinical and final commercial manufacturing processes are comparable, and therefore, they support our ability to utilize the clinical data across all clinical studies in our TSHA-102 development program in our BLA submission. The ability to leverage the totality of evidence to support the long-term clinical benefit of TSHA-102 would strengthen the overall package and support a potentially expedited BLA submission based on the 6-month interim analysis. Turning to our clinical progress. We further advanced dosing in the REVEAL pivotal trial with multiple patients dosed across multiple clinical trial sites. In parallel, enrollment in the ASPIRE trial is ongoing across multiple sites, and we remain on track to complete dosing in both trials this quarter. I am pleased to share that both high and low-dose TSHA-102 continue to be generally well tolerated with no treatment-related serious adverse events or dose-limiting toxicities observed in all patients treated across the REVEAL Phase I/II and REVEAL pivotal trials as of the May 2026 data cutoff. We look forward to reporting longer term data from all 12 pediatric, adolescent and adult patients treated in Part A of the REVEAL Phase I/II trials later this quarter. Our pivotal development strategy is grounded on the rigor of our natural history analysis and Part A data collection and evaluation with trial design, endpoints and statistical analyses developed based on discussions and written feedback from the FDA. Accordingly, developmental milestones in Part A are assessed using 3 structured criteria, all of which must be met in order for a developmental milestone to qualify as a gain or a regain post TSHA-102. First, all caregivers must complete the clinician-administered historical milestone questionnaire used in the natural history study. This allows us to identify milestones eligible for gain or regain by confirming whether a milestone was never previously achieved or was lost long enough ago that the likelihood of a spontaneous gain or regain is less than 6.7%. Establishing a documented time since loss is fundamental to accurately differentiate a true regain from natural variability as each of the 28 milestones has its own determinant. A simple baseline assessment is not sufficient documentation to support a rigorous statistical assessment and is susceptible to false positives. Our approach ensures milestone history is captured accurately so that only true open milestones are counted as gains or regains. Second, the milestone gain must be captured by post-treatment video documentation. This provides evidence of milestone gains that can be objectively reviewed, which brings me to the third criterion. Video evidence must be independently evaluated by multiple external raters using a prespecified definition of achievement for each milestone from our pivotal trial protocol. We believe these criteria are essential for interpreting functional outcomes and provide a reliable assessment of TSHA-102's efficacy as we advance towards registration. We believe our Part A data accurately reflect the outcomes we expect to observe in the pivotal trial as they are evaluated using the same FDA-aligned criteria for the pivotal trial protocol. As a reminder, we presented data from Part A of the REVEAL Phase I/II trials last year, demonstrating an 83% response rate at 6 months post treatment with 5 of the 6 patients treated with the high-dose TSHA-102 gaining or regaining at least developmental milestone. By 9 months post treatment, the data demonstrated a 100% response rate across the 6 treated high-dose patients. In addition to the 22 developmental milestones gained across the 10 patients treated with TSHA-102, patients also demonstrated a total of 165 additional functional skills and improvements across the core domains of Rett syndrome, an average of approximately 19 functional gains per patient. We observed a consistent pattern of early gains that were sustained with additional gains seen over time, demonstrating the deepening of effect. In our upcoming Part A data readout, we expect to report longer term follow-up, including at least 12 months of data from all 12 patients treated with TSHA-102. These results will include functional gains based on natural history-defined developmental milestones and additional functional skills and improvements impacting the activities of daily living that are meaningful to the caregivers and clinicians. We will be hoping to see a consistent pattern of early responses that are sustained and deepen over time across functional gains and clinical outcome measures in the treated patients. We believe this longer term follow-up will provide important context around the durability, deepening of effect and consistency in responses. With FDA alignment on the potential to pool data across the full TSHA-102 development program and our BLA submission, we believe the longer term Part A data has the potential to strengthen the overall BLA package and support an expedited submission. In parallel to our clinical and regulatory execution, we continue to build out our internal commercial infrastructure. We have strategically assembled a strong commercial leadership group, including senior hires who have deep expertise in commercial strategy, pre-commercial and product launch planning as well as payer and health care systems engagement within the gene therapy space. With these key roles now in place, we are focused on developing a strategic commercial strategy to prepare for a potential launch, and we expect to share additional details on our commercial plans in the second half of the year. I would now like to turn the call over to Suku to discuss evidence that further validates the TSHA-102 program and route of administration in more detail. Suku? Sukumar Nagendran: Thank you, Sean. We have continued to make meaningful progress advancing TSHA-102 towards registration and remain confident in its differentiated potential. A key design attribute of TSHA-102 is its minimally invasive intrathecal route of administration, which market research shows is strongly preferred by clinicians and caregivers over direct-to-brain central nervous system delivery. This preference is driven by its familiarity, accessibility and scalability, enabling broad access to treatment across institutions from major centers of excellence to regional and local sites. A peer-reviewed article was recently published by Frontiers in Medicine Gene and Cell Therapy, which highlights preclinical data we previously presented at the 2025 International Rett Syndrome Foundation Rett Syndrome Scientific Meeting. The data showed that intrathecal and direct-to-brain intra-cisterna magna administration demonstrated comparable, consistent and widespread distribution of AAV9 vector throughout the brain and spinal cord in non-human primates. We believe this further validates lumbar intrathecal delivery as a potentially safe, effective and minimally invasive approach to deliver a gene therapy to the central nervous system. In addition, on May 14, we plan to present new preclinical data that further validates the construct design of TSHA-102 at the ASGCT 2026 Annual Meeting. Consistent with previously published vector comparisons, the data demonstrated that the self-complementary AAV9 vector enables significantly higher protein expression compared to single stranded AAV9 in neuronal mouse cell models. The 30-fold higher transduction efficiency demonstrated in this study, along with the improved genomic stability of self-complementary AAV9, supports our ability to effectively deliver TSHA-102 to the central nervous system using a minimally invasive lumbar intrathecal administration. In addition, the data showed that the mini MECP2 protein used in our TSHA-102 construct was functionally comparable to the full-length MECP2 protein across molecular and biochemical functions. We believe these data support the strategic TSHA-102 construct design and provides important translational context for the early, sustained and deepening functional gains demonstrated across all patients previously reported in Part A of the REVEAL Phase I/II trials. We believe this supportive evidence, our continued FDA alignment on a registrational path and the clinical data generated to date support the potential for TSHA-102 to provide meaningful benefit to pediatric, adolescent and adult patients with Rett syndrome using a minimally invasive delivery approach that is scalable. Our focus remains on clinical execution and data generation as we work to complete dosing in our REVEAL pivotal and ASPIRE trials and report long-term data from Part A of our REVEAL Phase I/II trial this quarter. I would now like to turn the call over to Kamran to discuss financial results. Kamran Alam: Thank you, Suku. Research and development expenses were $33.8 million for the 3 months ended March 31, 2026 compared to $15.6 million for the 3 months ended March 31, 2025. The $18.2 million increase was primarily driven by BLA-enabling PPQ manufacturing initiatives performed during the 3 months ended March 31, 2026 and higher clinical expenses from the REVEAL Part A Phase I/II, Part B pivotal and ASPIRE trials. Compensation expenses, including non-cash stock-based compensation also increased as a result of additional research and development headcount. General and administrative expenses were $9.7 million for the 3 months ended March 31, 2026 compared to $8.2 million for the 3 months ended March 31, 2025. The increase of $1.5 million was primarily due to higher compensation expenses, including non-cash stock-based compensation expense and increases in consulting and professional fees, including commercial launch readiness initiatives. Net loss for the 3 months ended March 31, 2026 was $42.4 million or $0.12 per share compared to a net loss of $21.5 million or $0.08 per share for the 3 months ended March 31, 2025. As of March 31, 2026, Taysha had $276.6 million in cash and cash equivalents. We expect that our current cash resources will be sufficient to fund planned operating expenses into 2028. I will now turn the call over to Sean for his closing remarks. Sean? Sean Nolan: Thank you, Kamran. Our confidence in our differentiated TSHA-102 gene therapy candidate continues to strengthen based on the developments highlighted today. And we continue to believe TSHA-102 has the potential to deliver meaningful therapeutic benefit to a broad population of patients with Rett syndrome using a minimally invasive delivery approach. With a favorable tolerability profile demonstrated to date, dosing in the REVEAL pivotal and ASPIRE trials on track for completion in the second quarter of 2026 and a well-defined regulatory and commercial path, we're advancing toward potential registration with clarity as we work to bring a potentially transformative therapy to the Rett community. I will now ask the operator to begin our Q&A session. Operator? Operator: [Operator Instructions] Our first question today comes from Kristen Kluska from Cantor. Kristen Kluska: Congrats on these updates. So I wanted to ask you a little bit more about some of the data you're going to have at ASGCT. For the work you're doing that supports higher MECP2 protein expression with the self-complementary AAV9, can you tell us why this matters so much versus the obvious of just having more protein expression? Does this allow for a greater orchestra across more neurons? Does it mean a faster onset of action? What would you truly highlight here? Sean Nolan: Thanks for the question, Kristen. I think Suku and I can tag team this. But at a high level, I think what we wanted to do was really provide the why as to what the clinical result that we're generating is, right? I mean from a clinical perspective, in every patient treated, whether it's a pediatric patient, adolescent patient, adult patient, everyone has been a responder. We're seeing multiple skills and improvements across all of these patients and they happen quickly and then they improve over time and get deeper. And so the question is why does that occur? And I think what we're highlighting at ASGCT is the fact that the construct, which we purposely utilize self-complementary technology ultimately drives in this data set, a 30x transduction efficiency or protein expression than single strand does. And so that is a reason why you could potentially use a less invasive route of administration like intrathecal versus having to go with a closer to the brain approach. And usually, you have to do that because of a single strand. The other thing, too, is just reinforcing the fact that the mini MECP2 gene continues to show comparability. It's been published for over 15 years that this has been the case. But again, we just wanted to highlight that regardless of the genotype that we're seeing in these 12 patients that we've dosed to date and that we'll report on in a few weeks, they're all responding and they're responding across clinical domains. And the gene, the mini gene is very much a part of that because it essentially equals the full-length gene. And again, the reason we use the mini gene was so we could package the self-comp. So we're just trying to highlight the fact that the reason -- all the reasons that we put into building the construct are being demonstrated clinically and that this allows us to use a particular route of administration that we know is strongly preferred out in the community. Suku, I don't know if there's more you might want to add to that. Sukumar Nagendran: Yes, Sean, I have a few more points to add. So Kristen, thanks for that incredibly important question. What we've already shown with our REVEAL Part A program is that a simple lumbar puncture, a self-complementary mini gene construct using TSHA-102 gives you incredibly important clinical results from an efficacy standpoint that translates into a significant improvement in activities of daily living. So the clinical data at the present time from Part A now speaks for itself. So now when we work backwards and continue to further look at preclinical data, whether it's us or from other companies, it is very clear that a self-complementary construct turns on very quickly once given into the central nervous system, i.e., via the CSF. Once it turns on, it has rapid impact on one of the most important components of Rett syndrome, which is the autonomic dysfunction component, where we have impact pretty quickly usually within a couple of weeks post dosing. We've also shown repeatedly now in Part A that we have very positive clinical impact consistently regardless of age, genotype or phenotypic presentation of the patient with Rett syndrome, where there is an improvement in gross motor, fine motor skills or restoration of those skills, which have been lost over time, but also improvement in the ability to communicate as well as when it comes to social activities. So my point here is that a self-complementary stable construct turns on quickly, it persists and it continues to persist and build on top of all the preclinical data that we have that shows that a lumbar puncture with the right product can have a simple but consistent positive clinical response for a post patient population that has significant unmet medical need. And in this case, Rett syndrome. And I think we may have set the stage for an intrathecal lumbar puncture-based platform to treat difficult CNS diseases. Operator: Our next question comes from Salveen Richter with Goldman Sachs. Salveen Richter: Regarding the BLA submission pathway for 102, can you walk through the different scenarios here and whether approval based on the 6-month data should be considered the base case assumption? And how you characterize the willingness of the FDA to approve based on 6-month data sets and time lines around this, that would be great? Sean Nolan: Yes, Salveen, great question. We've been out talking with the investment community really since the beginning of the year, and this topic has come up. And so I think those that are on the call, this will sound very familiar, but we were very transparent with the FDA. Part of this meeting was trying to gain alignment and we were walking them through various scenarios. And we told them point blank that our preferred scenario would be a full approval at 6 months' worth of data. And the argument for that, right, I mean, generally, they like the precedent of 12 months of data for gene therapy, which is arguably probably pretty arbitrary, to be honest, but that's generally what they've held to. And I think our perspective on that is understood. But if we continue to demonstrate comparability with Part A, we're going to have years of data from those patients that we can use to support the durability. And their answer was essentially, look, ultimately, this is going to come down to the totality of the evidence. And this is something that if the company chooses to do, we will -- we are open to it and we will review that in due course, which is really the best answer you could possibly get, right, which is the door is open, let the data speak for itself. The second derivative of that, in our view, was basically if for whatever reason the FDA decides that let's just say they want to keep it as a precedent at 12 months, we would push hard for a rolling review because the CMC modules would be done, the preclinical modules would be done. And we can have things updated where the 6-month data is packaged in a way that they could look at that and also then there's less to review when you would submit the final 12-month data, and that can pull things forward a couple of quarters. And then obviously, the third scenario would be there may be nothing at all wrong with the data. They just want to see 12 months. So we feel in any of those scenarios, number one, there continue to be a positive and constructive dialogue with the agency. There was no opposition to anything that we put forward. There was an openness to it. Clearly, it's going to come down to the totality of the evidence and their comfort level around the data package that's put forward. But as we've said all along, the nice thing about this 6-month interim is it creates the optionality for us to potentially get this to patients faster. And my personal opinion, I can be wrong, is that almost regardless of what we come back with, I know everyone would prefer it's the fastest time point. And obviously, we're going to do everything we can to facilitate that. But we'll have clarity for the market. And even in the scenario -- and don't read into this, it's just even in the scenario where it's a 12-month ask, we can say that and you know what our 6-month data are and people can judge the probability of success, and then it's an execution story. So for all the reasons that we laid out in this call, we feel that there is strong evidence to push for the 6-month data. The fact that we've got comparability with the FDA on the CMC side is absolutely critical to this. And that opens the door for us to pool the Part A data alongside the pivotal Part B. And in our opinion, really should alleviate any concerns on the durability piece. So ultimately, we'll leave it at that. The nice thing is we've got this option -- these options in front of us, thanks to the data that we've put forward today and also the CMC quality that we've put forward today. So we're in the best possible position we can be. We've got a couple of cards that can fall our way, and we're excited about having this discussion with the FDA at the appropriate time. Operator: Our next question comes from Biren Amin with Piper Sandler. Biren Amin: Recently, the FDA Commissioner announced the real-time clinical monitoring program that enables the FDA to evaluate data real-time. Is that something that the company can leverage for REVEAL given the high unmet need in Rett syndrome, especially Sean, with the 6-month data and the agency potentially following patient data to 12 months during review under this program? So I guess that's the first question. And then second question for REVEAL. Do you expect to stop enrollment at 15 patients or could you potentially over-enroll as is typically the case with clinical trial management and execution? And if that's the case, how does the over-enrollment impact the effect size calculation for the study? Sean Nolan: Yes. Just real quickly on the real-time piece, I'll ask Suku to comment on that. But I would say we're always keeping our eyes open for what we could potentially do. Like the other one is the commissioner's voucher, right? Things are so dynamic up there. It can be difficult sometimes to tell what's afforded to you and what's not afforded to you. I think that what I just laid out in terms of scenarios, we feel very good about. If there's an opportunity for us to lever one of these additional pathways, sure, we would try to do that. But again, I don't want to try to make it sound like that's what we're attempting to do out of the gate here just because it's not as formalized and crystallized in terms of the time lines, what you need to meet the hurdle bar, et cetera. I don't know if there's anything you'd add to that, Suku. Sukumar Nagendran: Yes, Sean. I mean, Biren, thanks for that very interesting and important question because what the FDA has proposed, I think, could change the way clinical trials are overseen by the FDA with their direct hands-on experience and oversight. But at the same time, as the real-time data pours in, I think the regulators and the sponsors, clinical regulatory teams will have to work very closely to make sure appropriate interpretation is done when it comes to real-time safety data and efficacy data, because especially in the rare disease space, as we know, we are learning not only about the disease, but also the response to the therapeutic intervention at that point in time. And sometimes the real-time decisions versus a more time process-oriented decision could have significant impact and influence on programs. So I hope that helps, because at this time, we are kind of watching the process interestingly. And you mentioned the decision-making governance between the regulators and the sponsors are going to be critical to make sure real-time oversight of clinical trials will pay the dividends that the FDA hopes it will. Sean Nolan: Yes. And then the question around the potential for over-enrollment, I would say that you're always trying to balance the -- getting the appropriate patients in screened essentially, understanding that there could potentially be a screen fail. Like one of the criteria we have, right, there's a number of open milestones you must have, right, as an example. You could go through the screening and then find out that, that patient doesn't quite meet it. So you're going to want to have more patients than 15 going through the screening process. And if you do end up in a situation where you dose an extra patient or 2, we would be certainly willing to do that. I can just say that the effects on the statistics are minimal. I mean they would obviously look at the first 15 patients first and do the statistics on that. And then if you had another patient or 2, they would do the statistics on that, but they really don't change much. Anything else you would add there, Suku? Sukumar Nagendran: No, the only thing I would add there, Sean, is that as you said, the power and p-values for a patient sample size of 15, if it goes to 16 or 17 based on what Sean just described, it won't have a major impact on power or p-value for the study itself. And as you know, from REVEAL Part A, we already have 100% responder rate at 9 months with a small number of patients. And those observations, I think, are significant. And as you know, all we need is a 33% responder rate for our REVEAL Part B study. So let us see what the eventual data pans out, but I think we are confident that the Part A data hopefully should be reproduced in Part B as well. Sean Nolan: Yes. I think the key, Biren, is just simply that the null hypothesis is so low. It's effectively 1 patient spontaneously having an effect. So because of that number being such a low aspect, the overall end doesn't really change things very, very much. But good question. Thank you. Operator: [Operator Instructions] And our next question comes from Tazeen Ahmad from Bank of America. Wesley Yon: This is Wesley on for Tazeen. I had a question on sort of the mechanics of the Part B portion of the study compared to the Part A. Are the like assessments being done of the patients, the treated patients being done in the same way in Part B to Part A? Who is doing the video recordings? And with regards to sort of the patients that you are currently screening and plan to dose, are those sort of sites and investigators similar between Part B and Part A? I'm just trying to like look for any color on sort of straight lines we can draw from the 12-month update you're going to share soon to what we can expect and how the Part B is running. Sean Nolan: Thanks for the question. And Suku, we can tag team this. Our view is that the read-through from the upcoming data review that we're going to put out should be pretty direct for all of you. And that's why we've put so much emphasis around the rigor of the data collection in Part A. We spent a lot of time on the call talking about that. And it starts with the fact that, number one, what we rate is -- so first of all, all of our milestones for the primary endpoint are prespecified, right? There's clear definitions for those. And those demonstrations are from videos that are conducted in the study itself. So when people -- the way it's been working is that people are doing the hand function test or the RMBA or the Mullen. If we have video of them doing a milestone, that video then goes outside the company and 2 of 3 raters have to adjudicate that as a milestone. So the company has nothing to do with what is declared a milestone. And I think that has been a big part of the reason why the agency has been open to our data set and the interim analysis is that we had rigorous video evidence that was adjudicated outside the company. Now the other side of this coin is that the Mullen, which is another video tape demonstration and the RMBA are also supportive data sets that the agency sees. Again, those are on video. The Mullen also gets centrally adjudicated and the FDA -- and the RMBA is done in the clinic by the physician, right? So there's no real way to be putting your thumb on a scale and making this data subjective. It's very objective. So I think this is a good read-through to Part B. The only difference in Part B is that we're going to have a standalone assessment of all of the milestones. So I would argue that we're probably undercounting milestones in Part A and that we have a better chance of counting more milestones in Part B because there's a standalone test. We spent a lot of time with the FDA developing this test. We have training modules around this test. The test is conducted in the hospital by trained assessors at the hospital. So this is not done at home. The parents aren't doing this. This is very prescriptive and it's done in-house. Those videos then go outside the hospital to the raters where they remain blinded until they break -- until the 6-month time period where they break the blind for all of the 15 patients and review those videos. So the whole point of what we've been trying to emphasize since we began reporting data on milestones is clear definitions, rigorous baseline collection with videos assessed by central raters. It's going to be very similar in Part B, but even more rigorous. And I think there's more ability to capture milestones because we now have a standalone test. So hopefully, that gives you a perspective there, but I think the read-through should be pretty direct when we update you in a few weeks. Operator: Our next question is from Maury Raycroft with Jefferies. Unknown Analyst: This is James on for Maury. For the 12-plus months of follow-up in the 2Q update, how are you setting expectations for the early milestones and skills deepening versus new more complex milestones and skills appearing between 6 and 12 months? And how do you plan to communicate that in the update relative to the last presentation last year? And also, should we expect a potential safety update from the REVEAL pivotal cohort around IRSF or how should -- or should we expect that update at a later point after IRSF? Sean Nolan: Yes. To answer your second question first, I mean, even today, when we said that as of the March safety cutoff, that was inclusive of the REVEAL Part A and also the pivotal trials and ASPIRE. So that's all the studies that we're running right now. You just got a safety update on no treatment-related SAEs and DLTs. And we'll continue to do that on a quarterly basis. And the first part of the question, could you repeat that? I already lost it. Unknown Analyst: So the 12-plus months follow-up in the 2Q update, how are you setting expectations? Sean Nolan: Yes. I mean to be very simple, and I'll turn it over to Suku, what we've seen on the reports that we did last time was that there's early responses. There's more responses that occur as time goes on relative to milestones, relative to skills and improvements. And that the things that you had, you get better at and you're also developing new milestones, new skills and new improvements. That's what we would expect to see at 12 months. Sukumar Nagendran: Yes, Sean, as you have emphasized, what we will communicate is the rapid, consistent, persistent clinical impact of TSHA-102 in patients with Rett syndrome regardless of genotype, phenotype or age. And I would also emphasize that we hope that we can continue to show a significant collective improvement in "skills" that per patient could go above the 19 per patient that we disclosed this morning when Sean did his segment of the communication. So just pay attention to that as well because I think a component of reaching developmental milestones in a validated manner, as we've already discussed and described, which the FDA truly likes. And I'm going to emphasize these are done in a blinded reviewer, expert reviewer fashion and not done at home by caregivers, which usually the FDA has questions around. So I hope that our 12-month plus data disclosure further enhances the confidence in what TSHA-102 can contribute potentially in a transformative manner to this patient population. Sean Nolan: Yes. I guess last comment there, James, is that we don't expect to see any type of a plateau. We expect to continue to see improvements and new improvements over time based on the historical disclosures. Operator: Our next question comes from Gil Blum from Needham & Company. Gil Blum: Maybe just another one on the 6 months interim, as a clarification, the FDA basically has not given a clear feedback as to what it thinks about this 6-month interim. Would you say that what would dictate the decision here would be the data itself and the 12-month data that you're going to present at IRSF? Sean Nolan: Gil, can you repeat that? I honestly didn't quite get the point of the question. Gil Blum: The point is you haven't really gotten clear FDA feedback as it relates to the 6-month interim. They're actually waiting for the data. Is that fair? Sean Nolan: Yes. I mean I think that is fair. I think the clear feedback we got is that it's an option for us. And that's all you can ask for at this particular point in time. They've consistently said since we put that disclosure out, I guess it was June '25 where we started talking about that. It's always been something that's enabled. We just confirmed, and we've gotten a lot of questions from investors like, hey, when was the last time you talked to the FDA? It's like, well, we talked twice in the last few months here, once on CMC and once on our first breakthrough meeting. And we went back through, we got confirmation on the design, on the endpoints and our scenarios that I went through. And they're like, yes, I mean that is an option for you. It's going to depend on the data in terms of approvability. So you're never going to get anything better than that, which is why we were so with the outcomes from that meeting. Gil Blum: Okay. So to summarize, they're open to it. Sean Nolan: I didn't hear that. Sukumar Nagendran: Yes, they are open to the 6-month... Sean Nolan: Yes, yes. And it's in writing, by the way. I mean, so it's as good as you can get. There was very much an open-mindedness to this. And it's an open door for us at this point in time, and it's going to be won by the data. Operator: [Operator Instructions] Our next question is from Chris Raymond with Raymond James. Christopher Raymond: Maybe just 2 here. Just on the Process Performance Campaign or PPQ. You mentioned FDA has agreed on equivalency between the clinical and the commercial manufacturing. Maybe just can you give a little bit more color on what activities, what are sort of the pinch points, I guess, in terms of getting to having something you can submit in Q4 between now and then? And then one of the things that kind of struck us, we've done some KOL work where people seems physician -- the physician community seems very aware that you have a broad range of ages in your data. Maybe just talk a little bit more about the importance of enrolling a broad age range? And how that's being received by the clinical community from your perspective? Sean Nolan: Sure. So Chris, starting with the PPQ, we aligned on comparability when we had the clinical lot that was in Part A, and then we ran our, call it, our final commercial process. We ran a lot of that. And so it was 1:1, and the FDA deemed that, that was analytically comparable. And what you have to continue to do as you produce more lots is demonstrate that there's -- those additional lots are also comparable. So at this last meeting, we shared with them multiple additional lots that we'd run, and they continue to say that we're comparable. Now as you go into PPQ, you're generally doing 2 or 3 additional runs and then you share that data with the FDA. So we're in the process of doing those runs right now. Assuming those runs continue to be demonstrating comparability, that's when you're able to pool the data. So the fact that we've been able to do it with multiple runs so far gives us a lot of confidence. There's a strong alignment with the FDA. And then we take that data package and the next time we meet with them, we share that with them, and that's kind of the next step. So we feel like we're in a really good position on the CMC side, and we have been for quite some time. It is not on the critical path to the BLA submission. So that's that. As it relates to the broad ages of enrollment, if you think about the prevalent population, 85% of the prevalent population is over the age of 10. So demonstrating effect across pediatric, adolescent and adults is very, very important, because as we've done market research with both caregivers and with clinicians, they plan on offering it across the age spectrum. And they're planning to offer it because there's demonstrated effect across the age spectrum. So we feel that we're in a good position to serve the broad community who is requesting gene therapy because of the data that we've generated, and that's why we're being thoughtful about making sure that there's representation across the age spectrum in Part B. So our whole goal is to make this available for all patients with Rett syndrome and the data continue to support that. And I can tell you that the demand is high across the age groups based on what we've seen so far. Operator: Our next question is from Jack Allen with Baird. Jack Allen: Congrats on the updates. It sounds great to hear that enrollment is on track to be concluded in the second quarter of this year. I guess my question is pretty simple, and that I was wondering if you could provide any additional color surrounding how far you are as it relates to completing enrollment? How many patients have been dosed in the study? And then maybe if that's a little too direct, if you could just speak to the enthusiasm you're seeing from the patient community and the interest in the trial? Sean Nolan: Yes. I think Suku can take the second part of the question. I mean we're not going to give specifics. I would just say the demand is super high. It's high across the age spectrum, multiple sites -- we've got 10 sites that are active. Multiple patients have been dosed across multiple sites. Most of the sites have multiple patients. So I mean, do you want to talk a little bit about the enthusiasm and the demand that we're seeing across the spectrum? Sukumar Nagendran: Absolutely. So we have multiple centers of excellence who are part of the clinical trial, and they all have 100, 200-plus patients. Many of the patients' caregivers and parents have been very enthusiastic about being screened and enrolling in our trial. So I would say with confidence that we are over-enrolled and we have more than enough patients to dose to meet the 15 -- the number of 15 or a little bit more. So we should be -- we will be meeting our commitment to complete dosing for both REVEAL Part B and ASPIRE by the end of the second quarter this year. Operator: Our next question is from Whitney Ijem from Canaccord Genuity. Whitney Ijem: Just thinking about durability, how often are patients assessed in Part A? And I guess I'm just wondering if there's a scenario where later this year, either we or the FDA is getting like an 18-month update on those patients and then potential for longer term updates going forward? Sukumar Nagendran: Yes. Thanks for that question, Whitney. That's actually a very important question that you raised. So given that we have a Part B ongoing, and we have an agreement with the FDA that the 6-month interim analysis once all 15 patients in Part B are dosed would be considered based on the efficacy and safety data for potential full approval of our product, the REVEAL Part A long-term data from a clinical standpoint, safety and efficacy, I think could significantly also impact the 6-month interim analysis from Part B collectively driving towards the full approval. And Sean clearly described that the FDA is aligned with us when it comes to the CMC process and the comparability technicalities between the Part A product and the Part B product. So to really answer your question on Part A, the long-term data, I think, up to 18 months being evaluated per the protocol post 12 months every quarter, I think it's going to be also important to the collective 6-month interim analysis. And if the 6-month interim analysis gives very useful clinical data, and Sean described the other scenario for Part B where you might need 12-month data as well, the REVEAL Part A persistence of effect long term will also, I think, influence further the confidence that our product will have immediate, consistent and persistent effect long term as well in this patient community. Sean Nolan: Yes. The only thing I would add, Whitney, is when we report the data, we will also report the data that's greater than 12 months. So you should have a real good sense of what's happening over time. Operator: Our next question is from Evan Seigerman with BMO Capital Markets. Malcolm Hoffman: Malcolm Hoffman on for Evan. Thinking about potential commercial manufacturing, I just wanted to ask what redundancies exist across TSHA-102 manufacturing chain that could help if there were any disruptions to the process? Kamran Alam: Yes. So to answer the question, so we currently are at Catalent, and Catalent's Baltimore, Maryland facility has obviously been inspected and they have extensive gene therapy manufacturing experience. And we feel really confident in the team that's at Catalent and our oversight of the team there. And importantly, as Sean mentioned earlier, we have ensured that based on our lock manufacturing process, CMC is not on the critical path to a potential BLA submission. And as it pertains to downstream potential redundancy in manufacturing, that's something as we get closer to Part B interim data readout. And as we get closer to a potential BLA submission, that's something we will evaluate to mitigate any potential disruption to supply chain. But we feel really confident given Catalent's manufacturing experience in that particular facility in Baltimore that, that facility can meet our ultimate commercial demand. Sean Nolan: And Evan, that's where Sarepta is making Elevidys as well. And so it's been FDA inspected, and they're very familiar, as Kamran said, with gene therapy commercial scale. So we feel very confident about that. Operator: Our next question is from Yanan Zhu with Wells Fargo. Unknown Analyst: This is Jeff on for Yanan. Today and in the last couple of months, market research has been touched on, indicating strong demand for gene therapy in Rett and a clear preference for intrathecal delivery, including mentioning 80% of caregivers and clinicians are seeking gene therapy for their patients. Can you provide any additional color or details on this market research in terms of if you tested any product profiles for TSHA-102 and patient -- physician preference specifically for TSHA-102? Sean Nolan: Yes. I mean -- and there'll be more to come in the second half, deeper dives on the commercial aspect of things. But we essentially tested with physicians. So it was about half the physicians were at centers of excellence, half were not at centers of excellence. And then we also separately ran a study with caregivers of Rett patients or children with Rett across the age spectrum. And we kept it pretty simple. I mean we basically -- our product profile was -- our product profile that you've effectively seen, the responder rate, the CGI scores on average with the duration of time that we've been testing these patients. Think about the last data update we gave last year and the deck that we used, it was effectively that on a one pager. And then we just toggle that with is it intrathecal or is it ICV? What would it matter, assuming the same set of data? And so number one feedback consistently in both groups, physicians and the caregivers was very high interest in gene therapy. They realize that you want something that treats the root cause. So there's a very high interest in seeking that out, number one. Number two, what was interesting is it's also -- there's high treatment being sought across the age groups, including those over 30. So that also was encouraging. And then when you distill this down to make it real simple, and again we didn't want to make it too technical at first. I think more has to be shown to get more precise on comparative product profiles. But if all things are equal on safety and efficacy, obviously, there's a preference for the least invasive route, both in terms of perceived safety, but also just in terms of some of the physicians were making the point on throughput in the institutions that it's a lot easier to put -- let's just say you had 100 patients at an institution, it's easier to stage and manage those patients efficiently using intrathecally versus if you have to fight for OR time, neurosurgeon time, et cetera, it's harder to do that. You're going to have more intrusions, you're going to have more emergencies coming in that you're going to have to work to allocate time. So the scalability effect was something that was also quite top of mind for the physician group. So hopefully, that gives you a little flavor for the data. Operator: Our next question comes from Silvan Tuerkcan with Citizens. Silvan Tuerkcan: I maybe just wanted to follow-up on the intrathecal injection here. So that is not a procedure, right? So that can be done in the outpatient setting versus maybe some of other routes of administrations that may potentially come to the market as well. Can you just speak about that and potentially the cost differential between a full procedure that would require OR time in neurosurgery versus not? And then I don't know if you can comment on this, but do you know the screen fail rate that you currently have? And is that predominantly because of the strictness around the baseline measures? Sean Nolan: Yes. In terms of the first question, what we're doing is a 20-minute lumbar puncture administration with mild or no sedation. So the patient can easily have this done and be out of the hospital well within... Silvan Tuerkcan: Same day. Sean Nolan: Yes, same day, well within 24 hours. The ICV approach, obviously, you need to be in the OR for that. You have to have a neurosurgeon do the procedure. And so there is greater time and cost associated with that procedure. In terms of breaking it out, that's something we can talk more about in the second half. But just from an efficiency perspective, the ability to give someone a lumbar puncture, obviously, you can do that in various spots throughout the hospital and do it safely. That's not the case with ICV. I mean there are certain parameters that you're going to have to have, certain staff that you're going to have to have, including neurosurgeons to do the procedure itself. And keep in mind that the OR time is booked in advance. There's only so much OR space. There's only very few neurosurgeons to do these procedures. So my point is that and the point that the physicians were making is that if you have a large number of patients, it would be much more efficient in the institution to be able to dose them on the -- via the intrathecal route for the reasons that I gave. The second question, I didn't quite get. So I don't know if anyone around the table got that or Silvan, if you could repeat that, I didn't get it. Silvan Tuerkcan: Yes. And obviously, the trial is ongoing. So -- but if you could just speak to the current screen fail rate, just to give a feel of are there -- is there a significant patient population out there that just cannot qualify for this therapy because, let's say, they're too advanced or not advanced enough or do you have any data points in that direction? Sukumar Nagendran: So Silvan, you asked actually a very interesting and important question, because remember, Rett syndrome, there are multiple different genotypes. There is a very differentiated phenotypic presentation, meaning multiple phenotypes that present as Rett syndrome. And then you also have the complexity of mosaicism when it comes to central nervous system. So it's a unique combination that eventually results in a complex clinical presentation. And what we've shown in REVEAL Part A is that regardless of genotype or phenotypic presentation or age, our gene therapy given through a simple lumbar puncture consistently provides superior clinical efficacy with no major safety concerns at this point in time. When it comes to screen failure rates, in Part A, as far as I recall, there were no screen failures. In Part B, we have not discussed the screen failures publicly at this point in time. But they are minimal. And given that the common route to the disease is a lack of MECP2 or minimal MECP2 levels that have clinical efficacy or impact on the patient, restoration of MECP2 levels using TSHA-102 in general, addresses the lack of MECP2 and has superior clinical efficacy results up to now. So my assumption here is as we experience and complete Part B REVEAL study and ASPIRE that screen failure or loss of market, I guess, a clinical market access to a large group of patients is not an issue and will not be an issue. I hope that answers your question. Operator: This does conclude our question-and-answer session. I would now like to turn it back to Sean Nolan, Chairman and CEO. Sean Nolan: Thanks to everyone who called in. I really appreciate the time and interest in Taysha. Have a great day. Operator: Thank you for your participation in today's conference. This does conclude the program. You may now disconnect. 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This article is a transcript of this conference call produced for The Motley Fool. While we strive for our Foolish Best, there may be errors, omissions, or inaccuracies in this transcript. As with all our articles, The Motley Fool does not assume any responsibility for your use of this content, and we strongly encourage you to do your own research, including listening to the call yourself and reading the company's SEC filings. Please see our Terms and Conditions for additional details, including our Obligatory Capitalized Disclaimers of Liability. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy. Taysha (TSHA) Q1 2026 Earnings Transcript was originally published by The Motley Fool

Neurogene Stock Plummets 44%: Is All Hope Lost for This Biotech?" Taysha Gene Therapies (NASDAQ:TSHA) executives highlighted regulatory progress, ongoing clinical enrollment, and manufacturing preparations for its Rett syndrome gene therapy candidate TSHA-102 during the company’s first-quarter 2026 earnings call, while also reporting a wider year-over-year net loss driven by increased development and manufacturing activity. CEO Sean Nolan said the company recently held its initial Breakthrough Therapy Type B multidisciplinary meeting with the FDA, where the parties “reaffirmed alignment on the planned pathway toward a BLA submission for TSHA-102,” including pivotal trial design, endpoints, and “BLA submission scenarios, including the potential to submit for approval based on a six-month interim analysis from the REVEAL pivotal trial.” → Berkshire Hathaway’s Record Cash Hoard: Why and What's Next? 3 Small-Cap Stocks For Your Fall Shopping List Nolan described the agency’s position as dependent on the “totality of the evidence,” adding that FDA feedback left “the door…open” to an approval submission based on six-month data, while acknowledging the agency’s typical preference for 12 months of gene therapy follow-up. He also said Taysha would consider approaches such as a rolling review if the FDA ultimately preferred longer follow-up, given that CMC and other modules could be submitted earlier. In response to investor questions, Nolan reiterated that the company’s preferred scenario is “a full approval at six months worth of data,” but he emphasized the decision would be “won by the data.” → A Prada Payday: Is AMC Back in Style? Nolan said the company held a Type C meeting with the FDA in the first quarter, during which the FDA endorsed Taysha’s proposed process performance qualification (PPQ) campaign strategy to support a planned BLA. The company initiated the “BLA-enabling PPQ campaign” in April and expects to complete execution by the fourth quarter of 2026. Nolan also noted that the FDA previously agreed TSHA-102 material produced from clinical and final commercial manufacturing processes is comparable, which he said “may support our ability to utilize the clinical data across all clinical studies” in a future BLA submission. In Q&A, he said comparability has been supported across multiple manufacturing runs and that additional PPQ runs are in progress. → Insider Sales: Top AST SpaceMobile Insider Cuts Postion Over 30% On manufacturing redundancy, CFO Kamran Alam said TSHA-102 is being made at Catalent’s Baltimore facility, which he said has been inspected and has “extensive gene therapy manufacturing experience.” Alam added that the company will evaluate downstream redundancy closer to a potential BLA submission to mitigate supply-chain disruption risk. Nolan said Taysha has continued dosing in the REVEAL pivotal trial across multiple sites and that enrollment in the ASPIRE trial is ongoing, with the company “on track to complete dosing in both trials this quarter.” He added that as of a May 2026 data cutoff, both high- and low-dose TSHA-102 “continue to be generally well-tolerated,” with “no treatment-related serious adverse events or dose-limiting toxicities observed” across patients treated in the REVEAL phase I/II and pivotal studies. The company also previewed a longer-term data update expected later in the second quarter. Nolan said Taysha plans to report longer-term data from all 12 pediatric, adolescent, and adult patients treated in Part A of the REVEAL Phase I/II trial, including “at least 12 months of data from all 12 patients treated with TSHA-102.” He said the update is expected to include functional gains measured by natural history-defined developmental milestones, along with additional functional improvements meaningful to caregivers and clinicians. Management also discussed how Part A milestone outcomes are evaluated, emphasizing a three-part approach that includes caregiver completion of a clinician-administered historical milestone questionnaire (used to determine whether a milestone is eligible for gain/regain), post-treatment video documentation, and independent evaluation by multiple external raters using predefined milestone definitions from the pivotal protocol. Nolan reiterated previously presented Part A results, stating the company last year reported an 83% response rate at six months post-treatment among high-dose patients, rising to 100% at nine months in the six high-dose patients. He added that across 10 treated patients, Taysha observed 22 developmental milestones gained, as well as 165 additional functional skills and improvements across core Rett syndrome domains—an average of about 19 functional gains per patient. In Q&A, Nolan said Part B uses a similar, video-based approach, with central adjudication by independent raters. He said the primary difference is a “standalone assessment of all of the milestones” in Part B, which he suggested could improve capture of milestone changes compared to Part A. President and Head of R&D Sukumar Nagendran discussed recently published preclinical data in Frontiers in Medicine, Gene & Cell Therapy, which he said supported the minimally invasive intrathecal route of administration. According to Nagendran, the data showed intrathecal and direct-to-brain intracisterna magna administration resulted in “comparable, consistent, and widespread distribution of AAV9 vector throughout the brain and spinal cord in non-human primates.” Nagendran also said Taysha plans to present additional preclinical data on May 14 at the ASGCT 2026 annual meeting. He said the company’s self-complementary AAV9 vector demonstrated “significantly higher protein expression” than single-stranded AAV9 in neuronal mouse cell models, including “30-fold higher transduction efficiency,” and that the miniMECP2 protein used in TSHA-102 was “functionally comparable to the full-length MECP2 protein across molecular and biochemical functions.” Responding to an analyst question, Nolan said the company aimed to connect construct design to clinical observations, including rapid and deepening functional improvements. Nagendran added that self-complementary constructs “turn on very quickly” in the CNS and said the company has seen early impacts in autonomic dysfunction “usually within a couple of weeks post-dosing,” based on Part A observations described on the call. Alam reported first-quarter 2026 R&D expenses of $33.8 million, up from $15.6 million in the first quarter of 2025, driven primarily by BLA-enabling PPQ manufacturing initiatives and higher clinical expenses across the REVEAL and ASPIRE trials, along with increased compensation tied to additional R&D headcount. General and administrative expenses were $9.7 million, compared with $8.2 million a year earlier, which Alam attributed to higher compensation and increased consulting and professional fees, including commercial launch readiness initiatives. Net loss was $42.4 million, or $0.12 per share, compared with a net loss of $21.5 million, or $0.08 per share, in the year-ago quarter. As of March 31, 2026, Taysha reported $276.6 million in cash and cash equivalents, and Alam said the company expects its current cash resources to fund planned operating expenses “into 2028.” Nolan said Taysha continues building internal commercial infrastructure and expects to share additional commercial planning details in the second half of 2026. He added that market research indicates clinicians and caregivers prefer intrathecal administration due to familiarity and scalability compared with direct-to-brain delivery, and he described TSHA-102 administration as a roughly “20-minute lumbar puncture” that can be completed with mild or no sedation. Taysha Gene Therapies, Inc (NASDAQ: TSHA) is a clinical-stage biotechnology company focused on developing gene therapies for rare monogenic diseases of the central nervous system. Using a proprietary adeno-associated viral (AAV) vector platform, the company engineers novel capsids and regulatory elements to optimize delivery and expression of therapeutic genes. Its pipeline features lead programs such as TSHA-102 for GM2 gangliosidoses (Tay–Sachs and Sandhoff diseases), TSHA-101 for GM1 gangliosidosis and TSHA-103 for aromatic l-amino acid decarboxylase (AADC) deficiency, alongside earlier-stage candidates targeting other life-threatening pediatric CNS disorders. Founded in 2019 and headquartered in Dallas, Texas, Taysha Gene Therapies completed its initial public offering in May 2021. The article "Taysha Gene Therapies Q1 Earnings Call Highlights" was originally published by MarketBeat. View MarketBeat's top stocks for May 2026.

Our analysts just identified a stock with the potential to be the next Nvidia. Tell us how you invest and we'll show you why it's our #1 pick. Tap here. Management reaffirmed alignment with the FDA on a streamlined BLA submission pathway for TSHA-102, including the potential for approval based on a 6-month interim analysis of the REVEAL pivotal trial. The company initiated the BLA-enabling Process Performance Qualification (PPQ) campaign in April 2026, with completion expected by Q4 2026, ensuring CMC activities remain off the critical path. Clinical strategy for the pivotal trial is grounded in a rigorous, FDA-aligned natural history analysis that uses three structured criteria—historical questionnaires, video documentation, and independent external rating—to differentiate true functional regains from natural variability. Management attributes the observed 'early, sustained, and deepening' clinical responses to the TSHA-102 construct design; preclinical data indicates the self-complementary AAV9 vector provides 30-fold higher transduction efficiency than single-stranded alternatives, supporting effective delivery via lumbar intrathecal administration. The choice of a minimally invasive lumbar intrathecal route of administration is a strategic differentiator, as market research indicates a strong preference among clinicians and caregivers over direct-to-brain delivery due to scalability and familiarity. The FDA has agreed that clinical and commercial manufacturing processes are comparable, allowing the company to pool data from all clinical studies to strengthen the totality of evidence in the BLA package. Taysha remains on track to complete dosing in both the REVEAL pivotal trial and the ASPIRE pediatric trial within the second quarter of 2026. The company expects to report longer-term follow-up data later this quarter, including at least 12 months of data from all 12 patients treated in Part A of the REVEAL Phase I/II trials. Management plans to share detailed commercial strategy and launch plans in the second half of 2026, following the assembly of a leadership team with deep gene therapy expertise. Current cash resources of $276.6 million are projected to fund planned operating expenses into 2028, providing runway through key regulatory and clinical milestones. R&D expenses increased to $33.8 million in Q1 2026, primarily driven by the initiation of the BLA-enabling PPQ manufacturing campaign and expanded clinical trial activities. Safety data as of the May 2026 cutoff showed TSHA-102 continues to be generally well-tolerated with no treatment-related serious adverse events or dose-limiting toxicities across all trials. The company highlighted new preclinical data to be presented at ASGCT 2026, which validates that the mini MECP2 protein used in TSHA-102 is functionally comparable to the full-length MECP2 protein across molecular and biochemical functions. One stock. Nvidia-level potential. 30M+ investors trust Moby to find it first. Get the pick. Tap here. Management stated the FDA is 'open' to a 6-month data submission, though the final decision will depend on the 'totality of the evidence' and durability shown in the pooled Part A data. If the FDA requires 12-month data, Taysha would pivot to a rolling review strategy to pull the timeline forward by several quarters. Management indicated they may dose slightly more than the planned 15 patients to account for screening dynamics, but noted this would not significantly impact the study's power or p-values. The null hypothesis is very low (effectively one patient showing spontaneous improvement), making the 15-patient sample size robust for the expected effect size. The self-complementary design 'turns on' quickly in the CNS, which management believes explains the rapid improvements in autonomic dysfunction observed within weeks of dosing. The 30x higher transduction efficiency compared to single-strand vectors is what enables the use of a less invasive intrathecal route while maintaining high protein expression. Intrathecal delivery is a 20-minute outpatient procedure that does not require OR time or neurosurgeons, offering significantly better scalability for institutions with large patient volumes. Market research suggests physicians prefer the intrathecal route due to throughput concerns and the ability to avoid the scheduling bottlenecks associated with surgical brain delivery.

DALLAS, May 06, 2026 (GLOBE NEWSWIRE) -- Taysha Gene Therapies, Inc. (Nasdaq: TSHA) (Taysha or the Company), a clinical-stage biotechnology company focused on advancing adeno-associated virus (AAV)-based gene therapies for severe monogenic diseases of the central nervous system (CNS), today reported financial results for the first quarter ended March 31, 2026, and provided a corporate update. “We continued to execute our clinical development strategy for TSHA-102 and recently reaffirmed alignment with the FDA on our pathway to a BLA filing, including trial design, endpoints and the potential to submit for approval based on the six-month interim analysis from the REVEAL pivotal trial,” said Sean P. Nolan, Chairman and Chief Executive Officer of Taysha. “We further advanced dosing in the REVEAL pivotal trial, with enrollment in the ASPIRE trial ongoing across multiple sites, and we remain on track to complete dosing in both trials this quarter. In parallel, we plan to report longer-term safety and efficacy data from Part A of our REVEAL Phase 1/2 trials in the second quarter of this year.” Mr. Nolan continued, “Our pivotal development strategy is grounded in the rigor of our natural history analysis and Part A data collection and evaluation, with trial design, endpoints and statistical analyses developed based on discussions with the FDA. In our upcoming Part A data readout, we expect to report longer-term follow-up, including at least 12-month data from all 12 pediatric, adolescent and adult patients treated with TSHA-102. These results will include functional gains based on natural history-defined developmental milestones and additional skills and improvements that impact activities of daily living. We look forward to sharing this data as we continue to demonstrate the differentiated opportunity for TSHA-102 to deliver meaningful benefit to a broad population of patients with Rett syndrome who continue to face high unmet medical need.” Recent Corporate and TSHA-102 Program Highlights Reaffirmed FDA Alignment on Planned BLA Submission Pathway for TSHA-102. Following a recent initial breakthrough therapy Type B multidisciplinary meeting with the U.S. Food and Drug Administration (FDA), Taysha reaffirmed alignment on the planned pathway to a Biologics License Application (BLA) submission for TSHA-102, including: Pivotal trial design and endpoints BLA submission scenarios, including the potential to submit for approval based on the six-month interim analysis from the REVEAL pivotal trial Further Advanced Dosing in REVEAL Pivotal Trial, with Multiple Patients Dosed Across Multiple Clinical Trial Sites. The single-arm, open-label trial is evaluating a single intrathecal (IT) administration of high dose TSHA-102 (1x1015 total vector genomes (vg)) in 15 females between the ages of 6 and <22 years in the developmental plateau population of Rett syndrome. The primary endpoint will assess response rate, defined as the percentage of patients who gain or regain ≥one of the 28 natural history-defined developmental milestones, with each patient serving as their own control. Standardized milestone assessments will be administered and captured on video at pre- and post-treatment timepoints, with determination of milestone gain/regain upon video-evidence review by independent, blinded central raters based on prespecified definitions of achievement for each milestone. The study includes a six-month interim analysis that may serve as the basis for BLA submission. Enrollment in ASPIRE Trial is Ongoing Across Multiple Clinical Trial Sites. The ASPIRE safety-focused trial is designed to support a planned BLA submission to enable broad labeling of TSHA-102 for patients aged ≥2 years with Rett syndrome. Taysha is enrolling three females with Rett syndrome, aged 2 to <4 years, to evaluate the safety and preliminary efficacy of a single IT administration of high dose TSHA-102 (1x1015 total vg), scaled to account for the lower brain volume in 2 to <4-year-olds. A minimum of three months of ASPIRE safety data will be included in the planned BLA submission, while efficacy in the 2 to <6-year-old population will be extrapolated from data collected in the REVEAL pivotal trial. TSHA-102 Continues to be Generally Well Tolerated. High dose (1x1015 total vg) and low dose (5.7x1014 total vg) TSHA-102 continue to be generally well tolerated with no treatment-related serious adverse events (SAEs) or dose-limiting toxicities (DLTs) in all patients treated in the REVEAL Phase 1/2 and REVEAL pivotal trials as of the May 2026 data cutoff. Initiated BLA-Enabling PPQ Campaign for TSHA-102 Using Commercial Manufacturing Process in April 2026. Following a Type C meeting in January 2026, the FDA endorsed the Company’s proposed Process Performance Qualification (PPQ) campaign strategy in support of the BLA submission, enabling the execution of the BLA-enabling PPQ campaign using the commercial manufacturing process. Initiating the PPQ campaign ensures Chemistry Manufacturing and Controls (CMC) activities remain aligned with clinical development timelines for the planned BLA submission. Peer-Reviewed Publication Further Validates Lumbar IT Dosing as a Safe, Effective and Minimally Invasive Approach to Deliver a Gene Therapy to the CNS. The publication titled “rAAV9 Vector Biodistribution in Nonhuman Primate Brain and Spinal Cord Following Lumbar Intrathecal Infusion” was published in Frontiers in Medicine – Gene and Cell Therapy (DOI: 10.3389/fmed.2026.1819594) on April 28, 2026. The publication includes preclinical data previously presented at the 2025 International Rett Syndrome Foundation (IRSF) Rett Syndrome Scientific Meeting, demonstrating IT and direct-to-brain intra-cisterna magna (ICM) administration showed comparable, consistent and widespread biodistribution of AAV9 vector throughout the brain and spinal cord regions in non-human primates. Abstract Accepted for Presentation at Upcoming American Society of Gene and Cell Therapy (ASGCT) 2026 Annual Meeting. The poster titled “Superior expression of self-complementary AAV and comparable functionality of mini and full-length MECP2 support the design of TSHA-102 for Rett syndrome” will be presented on May 14, 2026, and highlights new preclinical in vitro data demonstrating that self‑complementary AAV9 achieved significantly higher MeCP2 expression compared to single-stranded AAV9 in neuronal mouse cell models, and the comparable functionality of mini and full-length MECP2. Anticipated Milestones Completion of dosing in the REVEAL pivotal trial is expected in the second quarter of 2026 Completion of dosing in the ASPIRE trial is expected in the second quarter of 2026 Update on longer-term safety and efficacy data from Part A of the REVEAL Phase 1/2 trials (n=12) is expected in the second quarter of 2026 Completion of BLA-enabling PPQ campaign for TSHA-102 is expected in the fourth quarter of 2026 First Quarter 2026 Financial Highlights Research and Development Expenses: Research and development expenses were $33.8 million for the three months ended March 31, 2026, compared to $15.6 million for the three months ended March 31, 2025. The $18.2 million increase was primarily driven by BLA-enabling PPQ manufacturing initiatives performed during the three months ended March 31, 2026, and higher clinical expenses from the REVEAL and ASPIRE trials. Compensation expenses, including non-cash stock-based compensation, also increased as a result of additional research and development headcount. General and Administrative Expenses: General and administrative expenses were $9.7 million for the three months ended March 31, 2026, compared to $8.2 million for the three months ended March 31, 2025. The increase of $1.5 million was primarily due to higher compensation expenses, including non-cash stock-based compensation expense, and increases in consulting and professional fees, including commercial launch-readiness initiatives. Net Loss: Net loss for the three months ended March 31, 2026, was $42.4 million, or $0.12 per share, compared to a net loss of $21.5 million, or $0.08 per share, for the three months ended March 31, 2025. Cash and Cash Equivalents: As of March 31, 2026, Taysha had $276.6 million in cash and cash equivalents. The Company expects that its current cash resources will be sufficient to fund planned operating expenses into 2028. Conference Call and Webcast Information Taysha management will host a live conference call and webcast today at 8:30 a.m. ET to review its financial and operating results and provide a corporate update. Participants may access the live webcast of the conference call by visiting Taysha’s website. About TSHA-102 TSHA-102 is a self-complementary intrathecally delivered AAV9 investigational gene transfer therapy in clinical evaluation for Rett syndrome. Designed as a one-time treatment, TSHA-102 aims to address the genetic root cause of the disease by delivering a functional form of MECP2 to cells in the CNS. TSHA-102 utilizes a novel miRNA-Responsive Auto-Regulatory Element (miRARE) technology designed to mediate levels of MECP2 in the CNS on a cell-by-cell basis without risk of overexpression. TSHA-102 has received Breakthrough Therapy, Regenerative Medicine Advanced Therapy, Fast Track and Orphan Drug and Rare Pediatric Disease designations from the FDA, Orphan Drug designation from the European Commission and Innovative Licensing and Access Pathway designation from the Medicines and Healthcare products Regulatory Agency. About Rett Syndrome Rett syndrome is a rare neurodevelopmental disorder caused by mutations in the X-linked MECP2 gene encoding methyl CpG-binding protein 2 (MeCP2), which is essential for regulating neuronal and synaptic function in the brain. The disorder is characterized by loss of communication and hand function, slowing and/or regression of development, motor and respiratory impairment, seizures, intellectual disabilities and shortened life expectancy. Rett syndrome progression is divided into four key stages, beginning with early onset stagnation at 6 to 18 months of age followed by rapid regression, plateau and late motor deterioration. Rett syndrome primarily occurs in females and is one of the most common genetic causes of severe intellectual disability. Currently, there are no approved disease-modifying therapies that treat the genetic root cause of the disease. Rett syndrome caused by a pathogenic/likely pathogenic MECP2 mutation is estimated to affect between 15,000 and 20,000 patients in the U.S., EU, and U.K. About Taysha Gene Therapies Taysha Gene Therapies (Nasdaq: TSHA) is a clinical-stage biotechnology company focused on advancing adeno-associated virus (AAV)-based gene therapies for severe monogenic diseases of the central nervous system. Its lead clinical program TSHA-102 is in development for Rett syndrome, a rare neurodevelopmental disorder with no approved disease-modifying therapies that address the genetic root cause of the disease. With a singular focus on developing transformative medicines, Taysha aims to address severe unmet medical needs and dramatically improve the lives of patients and their caregivers. The Company’s management team has proven experience in gene therapy development and commercialization. Taysha leverages this experience, its manufacturing process and a clinically and commercially proven AAV9 capsid in an effort to rapidly translate treatments from bench to bedside. For more information, please visit www.tayshagtx.com. Forward-Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as “anticipates,” “believes,” “expects,” “intends,” “projects,” “plans,” and “future” or similar expressions are intended to identify forward-looking statements. Forward-looking statements include, but are not limited to, statements concerning the potential of TSHA-102 and Taysha’s other product candidates to positively impact quality of life and alter the course of disease in the patients Taysha seeks to treat, Taysha’s research, development, regulatory and manufacturing plans for its product candidates, communications with the FDA, including with respect to the BLA for TSHA-102, the potential for Taysha’s product candidates to receive regulatory approval from the FDA or equivalent foreign regulatory agencies, and whether, if approved, these product candidates will be successfully distributed and marketed and the potential market opportunity for Taysha’s product candidates, and the ability of Taysha’s current cash resources to support planned operating expenses into 2028. Forward-looking statements are based on management’s current expectations and are subject to various risks and uncertainties that could cause actual results to differ materially and adversely from those expressed or implied by such forward-looking statements. Accordingly, these forward-looking statements do not constitute guarantees of future performance, and you are cautioned not to place undue reliance on these forward-looking statements. Risks regarding Taysha’s business are described in detail in Taysha’s Securities and Exchange Commission (“SEC”) filings, including in our Annual Report on Form 10-K for the full-year ended December 31, 2025, which are available on the SEC’s website at www.sec.gov. Additional information will be made available in other filings that Taysha makes from time to time with the SEC. These forward-looking statements speak only as of the date hereof, and Taysha disclaims any obligation to update these statements except as may be required by law. Company Contact: Hayleigh Collins Senior Director, Corporate Communications and Investor Relations Taysha Gene Therapies, Inc. [email protected] Media Contact: Carolyn Hawley Inizio Evoke [email protected]