PHIO

Strategic milestone advancements for lead clinical candidate PH-762 Initiation of commercial scale API, long term non-clinical toxicology, completion of Phase 1b pharmacology, and new IP announcements King of Prussia, Pennsylvania--(Newsfile Corp. - August 6, 2026) - Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage siRNA biopharmaceutical company developing therapeutics using its proprietary INTASYL® gene silencing technology to eliminate cancer. Phio today reported its financial results for the quarter ended June 30, 2026, and provided a business update. "We realized significant headway on foundational building blocks advancing the PH-762 development program during the 2nd quarter," said Robert J. Bitterman, President and CEO. "Commencement of commercial scale API and dosing of a long term non-clinical study, both expected to be completed by year end, and final analysis of pharmacology outcomes from the Phase 1b trial should provide strategic flexibility for our next clinical study design, now in its final preparation." PH-762 Progress PH-762 was evaluated in a U.S. multi-center Phase 1b dose-escalating clinical trial through the intratumoral injection of PH-762 for the treatment of patients with cutaneous squamous cell carcinoma, melanoma and Merkel cell carcinoma. The trial (NCT 06014086) was designed to evaluate the safety and tolerability of neoadjuvant use of intratumorally injected PH-762, assess the tumor response, and determine the dose or dose range for continued study of PH-762. The study comprised 22 patients, including 20 with cutaneous squamous cell carcinoma, one with melanoma and one with Merkel cell carcinoma, which was completed in March of this year. Final comprehensive clinical study documentation is in final preparation stage, which will be submitted to the FDA. Phio intends to request an FDA meeting in the third quarter of 2026 to discuss next steps in the clinical trial design and development strategy for PH-762. Capital Sourcing 2Q 2026 In April 2026, the Company established an at the market (ATM) equity offering program pursuant to which it may offer and sell, from time to time, through H.C. Wainwright & Co., LLC, acting as sales agent, shares of its common stock, having an aggregate sales price of up to $6.36 million. Scientific News The Company presented its Phase 1b clinical trial data for PH-762 at multiple conferences and virtual life science events including Force Family Office Fireside Chats, the Life Sciences Investor Forum, and Renmark Financial Virtual Non Deal Road Show events. The Company has received multiple favorable patent actions encompassing three notices of allowance and one grant decision to further strengthen Phio's global intellectual property portfolio in the United States, Canada, and Japan. This reinforces the Company's commitment to developing and safeguarding breakthrough technologies for the INTASYL compounds. Recently, the Company announced the appointment of Dr. R. Todd Plott M.D. to the Board of Directors who will serve as a member of the Governance Committee. Todd Plott, M.D., is a board-certified dermatologist, accomplished researcher, inventor, and former FDA advisory committee member with more than 30 years of experience in dermatologic care and innovation. Financial Results Cash Position As of June 30, 2026, we had cash and cash equivalents of $13.0 million as compared with $21.0 million at December 31, 2025. The Company continues to focus its resources on advancing PH-762 while prudently managing general and administrative expenses and expects its existing cash and cash equivalents to fund planned operations into the second half of 2027. Research and Development Expenses Research and development expenses for the three months ended June 30, 2026 were $3.1 million, an increase of $2.0 million or 187%, compared with the three months ended June 30, 2025. The increase was primarily driven by a $0.9 million increase in nonclinical toxicology study costs, a $1.5 million increase in CMC (chemistry, manufacturing and controls) costs, offset by a $0.3 million decrease in clinical trial costs. Research and development expenses for the six months ended June 30, 2026 were $5.9 million, an increase $3.9 million or 200%, compared with the six months ended June 30, 2025. The increase was primarily driven by an increase of $1.8 million in nonclinical toxicology study costs, a $1.5 million increase in CMC costs, a $0.9 million increase in consulting, patent and employee-related costs, offset by a $0.3 million decrease in clinical trial costs. Management believes that research and development expenses will continue to increase as we advance our PH-762 program. General and Administrative Expenses General and administrative expenses for the three months ended June 30, 2026 were $1.2 million, a decrease of $49 thousand or 4%, compared with the three months ended June 30, 2025. General and administrative expenses for the six months ended June 30, 2026 were $2.6 million, an increase of $340 thousand or 15%, compared with the six months ended June 30, 2025. The increase was primarily driven by a $465 thousand increase in stock-based compensation expense, a $170 thousand increase in investor relations activities, offset by a $250 thousand decrease in financial outsourced accounting fees. Net Loss Net loss was $ 4.1 million for the three months ended June 30, 2026 as compared with $2.2 million for the three months ended June 30, 2025. The increase in net loss was attributable to higher research and development expenses associated with advancing the PH-762 program. About Phio Pharmaceuticals Corp. Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage biopharmaceutical company advancing its proprietary INTASYL® siRNA gene silencing technology to eliminate cancer. Phio's INTASYL compounds are designed to enhance the body's immune cells to more effectively kill cancer cells. Phio's lead clinical development program is an INTASYL compound, PH-762, that silences the PD-1 gene implicated in various forms of skin cancer. The Phase 1b trial (NCT# 06014086) is evaluating PH-762 for the treatment of cutaneous squamous cell carcinoma, melanoma and Merkel cell carcinoma. PH-762 is a potential non-surgical treatment for skin cancers. For additional information, visit the Company's website, www.phiopharma.com. Forward-Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words such as "intends," "believes," "anticipates," "indicates," "plans," "expects," "suggests," "may," "would," "should," "potential," "designed to," "will," "ongoing," "estimate," "forecast," "target," "predict," "could" and similar references, although not all forward-looking statements contain these words. These statements, which include statements, among other things, regarding the anticipated benefits of our INTASYL™ RNAi platform, our ability and plans to continue developing, advancing and protecting the breakthrough technologies underlying our INTASYL™ compounds, the results from our ongoing clinical trials, our expectations that our cash runway will extend into the second half of 2027, our expectations that commencement of commercial scale API and dosing of a long term non-clinical study will both be completed by year end, our belief that final analysis of pharmacology outcomes from the Phase 1b trial should provide strategic flexibility for our next clinical study design, our plans and expectations regarding FDA submissions and related interactions, including our intention to meet with the FDA in the third quarter of 2026 to discuss potential next steps in the clinical trial design and development of PH-762, our expectations that such FDA submissions and any related FDA meetings will clarify next steps in advancing the PH-762 development program, details regarding our planned non-clinical toxicology study, and our ability to support ongoing clinical development, operational requirements and strategic initiatives with the capital we currently have on hand, are based only on our current beliefs, expectations and assumptions and are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict and many of which are outside of our control. Our actual results may differ materially from those indicated in the forward-looking statements as a result of a number of important factors, including, but not limited to, the impact of future FDA interactions on the development of our product candidates; the impact to our business and operations by inflationary pressures; recession fears; the development of our product candidates, results from our nonclinical, preclinical and clinical activities, our ability to execute on business strategies, our ability to develop our product candidates with collaboration partners, and the success of any such collaborations, the timeline and duration for advancing our product candidates into clinical development, the timing or likelihood of regulatory filings and approvals, the success of our efforts to commercialize our product candidates if approved, our ability to manufacture and supply our product candidates for clinical activities, and for commercial use if approved, the scope of protection we are able to establish and maintain for intellectual property rights covering our technology platform, our ability to obtain future financing, market and other conditions and those risks identified in our most recent Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q under the caption "Risk Factors" and in other filings the Company periodically makes with the U.S. Securities and Exchange Commission. Readers are urged to review these risk factors and to not act in reliance on any forward-looking statements, as actual results may differ from those contemplated by our forward-looking statements. Phio does not undertake to update forward-looking statements to reflect a change in its views, events or circumstances that occur after the date of this release, except as required by law. Contact: Phio Pharmaceuticals Corp.Jennifer Phillips: [email protected] Corporate Affairs PHIO PHARMACEUTICALS CORP.CONSOLIDATED STATEMENTS OF OPERATIONS (Amounts in thousands, except share and per share data) (Unaudited) PHIO PHARMACEUTICALS CORP.CONSOLIDATED BALANCE SHEETS(Amounts in thousands, except share data)(Unaudited) To view the source version of this press release, please visit https://www.newsfilecorp.com/release/308057

Completion of Lead Clinical Candidate PH-762 Dose Escalation Trial for Treatment of Skin Cancer with Favorable Safety and Pathology Data Key Development Agreements Secured for Nonclinical Toxicology and U.S. cGMP Clinical Supply Manufacturing King of Prussia, Pennsylvania--(Newsfile Corp. - May 7, 2026) - Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage siRNA biopharmaceutical company developing therapeutics using its proprietary INTASYL® gene silencing technology to eliminate cancer. Phio today reported its financial results for the quarter ended March 31, 2026, and provided a business update. "We are enthusiastic with the successful completion of our Phase 1b clinical trial which now positions us for upcoming FDA interface which we expect will clarify next steps in advancing the PH-762 development program," said Robert Bitterman, President and Chief Executive Officer. Recent Corporate Updates PH-762 Progress PH-762 was evaluated in a U.S. multi-center Phase 1b dose-escalating clinical trial through the intratumoral injection of PH-762 for the treatment of patients with cutaneous squamous cell carcinoma, melanoma and Merkel cell carcinoma. The trial (NCT 06014086) was designed to evaluate the safety and tolerability of neoadjuvant use of intratumorally injected PH-762, assess the tumor response, and determine the dose or dose range for continued study of PH-762. The study was fully enrolled in November 2025 with a total of 22 patients, 20 with cutaneous squamous cell carcinoma, one with melanoma and one with Merkel cell carcinoma. The clinical phase of the trial is complete, and the final data is currently being analyzed. While final study data is pending formal analysis, an FDA submission intended to propose and seek guidance for next steps in clinical study design for PH-762 is targeted for the second quarter of 2026. Capital Sourcing During 2025, Phio strengthened its balance sheet through a series of equity financings and warrant exercises that generated approximately $23.7 million in net proceeds. These transactions extended the Company's cash runway into the first half of 2027 and will support ongoing clinical development, operational requirements and strategic initiatives. Scientific News The Company presented its Phase 1b clinical trial data for PH-762 at the American Academy of Dermatology (AAD) in the Late-Breaking Research Session in March 2026. In April 2026, the Company presented its lead clinical candidate, PH-762, and Phase 1b clinical trial results at multiple conferences including Deal Flow, Force Family Office Fireside Chats, the Investival Conference in Miami and the Centri Capital Conference in NYC. Financial Results Cash Position As of March 31, 2026, the Company had cash and cash equivalents of approximately $17 million as compared with approximately $21 million at December 31, 2025. In April 2026, the Company entered into an At The Market Agreement (ATM) with H.C. Wainwright & Co., LLC pursuant to which the Company may offer and sell shares of our Common Stock, having an aggregate price of up to $6.36 million. Research and Development Expenses Research and development expenses for the three months ended March 31, 2026 were $2.8 million, which was an increase of 215%, or $1.9 million, as compared with the three months ended March 31, 2025. This increase in research and development expenses was primarily driven by clinical trial, chemistry, manufacturing and controls (CMC) and toxicology expenses in connection with advancing our PH-762 program. Management believes that research and development expenses will continue to increase as we continue to advance our PH-762 program. General and Administrative Expenses General and administrative expenses for the three months ended March 31, 2026 were $1.4 million, which was an increase of 39%, or $400 thousand, as compared with the three months ended March 31, 2025. The increase in general and administrative expenses was primarily driven by employee related costs, investor outreach and professional fees. Net Loss Net loss was $ 4.0 million for the three months ended March 31, 2026 as compared with $1.8 million for the three months ended March 31, 2025. The increase in net loss was attributable to increases in research and development and general and administrative expenses cited above. About Phio Pharmaceuticals Corp. Phio Pharmaceuticals Corp. (Nasdaq: PHIO) is a clinical-stage biopharmaceutical company advancing its proprietary INTASYL® siRNA gene silencing technology to eliminate cancer. Phio's INTASYL compounds are designed to enhance the body's immune cells to more effectively kill cancer cells. Phio's lead clinical development program is an INTASYL compound, PH-762, that silences the PD-1 gene implicated in various forms of skin cancer. The Phase 1b trial (NCT# 06014086) is evaluating PH-762 for the treatment of cutaneous squamous cell carcinoma, melanoma and Merkel cell carcinoma. PH-762 is a potential non-surgical treatment for skin cancers. For additional information, visit the Company's website, www.phiopharma.com. Forward Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words such as "intends," "believes," "anticipates," "indicates," "plans," "expects," "suggests," "may," "would," "should," "potential," "designed to," "will," "ongoing," "estimate," "forecast," "target," "predict," "could" and similar references, although not all forward-looking statements contain these words. These statements, which include statements, among other things, regarding the anticipated benefits of our INTASYL™ RNAi platform, the results from our ongoing clinical trials, our expectations that our cash runway will extend into the first half of 2027, our expectations regarding timing of FDA submissions intended to propose and seek guidance for next steps in clinical study design for PH-762, our expectations that such FDA submissions and any related FDA meetings will clarify next steps in advancing the PH-762 development program, details regarding our planned non-clinical toxicology study, and our ability to support ongoing clinical development, operational requirements and strategic initiatives with the capital we currently have on hand, are based only on our current beliefs, expectations and assumptions and are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict and many of which are outside of our control. Our actual results may differ materially from those indicated in the forward-looking statements as a result of a number of important factors, including, but not limited to, the impact of future FDA interactions on the development of our product candidates; the impact to our business and operations by inflationary pressures; recession fears; the development of our product candidates, results from our nonclinical, preclinical and clinical activities, our ability to execute on business strategies, our ability to develop our product candidates with collaboration partners, and the success of any such collaborations, the timeline and duration for advancing our product candidates into clinical development, the timing or likelihood of regulatory filings and approvals, the success of our efforts to commercialize our product candidates if approved, our ability to manufacture and supply our product candidates for clinical activities, and for commercial use if approved, the scope of protection we are able to establish and maintain for intellectual property rights covering our technology platform, our ability to obtain future financing, market and other conditions and those risks identified in our most recent Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q under the caption "Risk Factors" and in other filings the Company periodically makes with the U.S. Securities and Exchange Commission. Readers are urged to review these risk factors and to not act in reliance on any forward-looking statements, as actual results may differ from those contemplated by our forward-looking statements. Phio does not undertake to update forward-looking statements to reflect a change in its views, events or circumstances that occur after the date of this release, except as required by law. Contact: Phio Pharmaceuticals Corp. Jennifer Phillips: [email protected] Corporate Affairs PHIO PHARMACEUTICALS CORP. CONSOLIDATED STATEMENTS OF OPERATIONS (Amounts in thousands, except share and per share data) (Unaudited) PHIO PHARMACEUTICALS CORP. CONSOLIDATED BALANCE SHEETS (Amounts in thousands, except share data) (Unaudited) To view the source version of this press release, please visit https://www.newsfilecorp.com/release/296434

Prestigious Late-Breaking Research Session Positions PH-762 as a Promising New PD-1 Directed Immunotherapy Candidate on March 28, 2026 at 3 PM (MDT) King of Prussia, Pennsylvania--(Newsfile Corp. - March 23, 2026) - Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage siRNA biopharmaceutical company developing therapeutics using its proprietary INTASYL® gene silencing technology to eliminate cancer. Phio announced today that a podium presentation addressing its lead product candidate, PH-762, will be given in the American Academy of Dermatology's Late-Breaking Research Session S034 on March 28, 2026 in Denver, Colorado. The presentation, entitled "PD-1 Directed Intratumoral Immunotherapy: Results of an Escalating Dose Study of INTASYL PH-762 for Cutaneous Carcinomas", will highlight results of Phio's Phase 1b clinical study (NCT 06014086) which evaluated the safety and tolerability of neoadjuvant use of intratumoral PH-762 in cutaneous squamous cell carcinoma (cSCC), melanoma and Merkel cell carcinoma. "The clinical study results are encouraging and firmly guide Phio to continued clinical development of this immuno-oncology therapy for cutaneous squamous cell carcinoma," said Mary Spellman M.D., Phio's acting Chief Medical Officer. "Preliminary clinical evidence demonstrates that intratumoral PH-762 may provide substantial clinical benefit, with notable pathologic response, and modest mean reductions in tumor burden following treatment." Recent Company Highlights Phio's lead clinical candidate, PH-762, is being evaluated as an intratumoral therapy for cutaneous squamous cell carcinoma (cSCC), melanoma and Merkel cell carcinoma. In its Phase 1b trial, Phio has reported that 22 patients completed treatment across five dose-escalation cohorts, with no dose-limiting toxicities or serious adverse events. The Company has also reported a pathological response rate in cSCC across all dosing cohorts of approximately 65%, including an 85% pathological response (6 of 7 patients) in the highest-dose cohort. Phio has indicated that FDA engagement regarding next-stage clinical development is targeted for the second quarter of 2026 and has reported cash and cash equivalents projected to sustain operations into the first half of 2027. About Phio Pharmaceuticals Corp. Phio Pharmaceuticals Corp. (Nasdaq: PHIO) is a clinical-stage siRNA biopharmaceutical company advancing its INTASYL® gene silencing technology in immuno-oncology. Phio's INTASYL compounds are designed to enhance the body's immune cells to more effectively kill cancer cells. Notably, INTASYL is a self-delivering RNAi technology focused on immuno-oncology therapeutics without the need for formulation enhancements or manipulations to reach its target. Phio's lead clinical program is an INTASYL compound, PH-762, that silences the PD-1 gene implicated in various forms of skin cancer. The Phase 1b trial (NCT# 06014086) evaluated PH-762 for the treatment of cutaneous squamous cell carcinoma, melanoma and Merkel cell carcinoma. PH-762 is a potential non-surgical treatment for skin cancers. For additional information, visit the Company's website, www.phiopharma.com. Forward Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words such as "intends," "believes," "anticipates," "indicates," "plans," "expects," "suggests," "may," "would," "should," "potential," "designed to," "will," "ongoing," "estimate," "forecast," "target," "predict," "could" and similar references, although not all forward-looking statements contain these words. These statements, which include statements regarding the anticipated benefits of our INTASYL™ RNAi platform, the results from our ongoing clinical trials, our expectations that our cash runway will extend into the first half of 2027, our expectations regarding timing of FDA submissions intended to propose and seek guidance for next steps in clinical study design for PH-762, details regarding our planned non-clinical toxicology study, and our ability to support ongoing clinical development, operational requirements and strategic initiatives with the capital we currently have on hand, are based only on our current beliefs, expectations and assumptions and are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict and many of which are outside of our control. Our actual results may differ materially from those indicated in the forward-looking statements as a result of a number of important factors, including, but not limited to, the impact to our business and operations by inflationary pressures, rising interest rates, recession fears, the development of our product candidates, results from our preclinical and clinical activities, our ability to execute on business strategies, our ability to develop our product candidates with collaboration partners, and the success of any such collaborations, the timeline and duration for advancing our product candidates into clinical development, the timing or likelihood of regulatory filings and approvals, the success of our efforts to commercialize our product candidates if approved, our ability to manufacture and supply our product candidates for clinical activities, and for commercial use if approved, the scope of protection we are able to establish and maintain for intellectual property rights covering our technology platform, our ability to obtain future financing, market and other conditions and those risks identified in our Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q under the caption "Risk Factors" and in other filings the Company periodically makes with the SEC. Readers are urged to review these risk factors and to not act in reliance on any forward-looking statements, as actual results may differ from those contemplated by our forward-looking statements. Phio does not undertake to update forward-looking statements to reflect a change in its views, events or circumstances that occur after the date of this release, except as required by law. For additional information, visit the Company's website, www.phiopharma.com. Contact: Phio Pharmaceuticals Corp. Jennifer Phillips: [email protected] Corporate Affairs To view the source version of this press release, please visit https://www.newsfilecorp.com/release/289479

Treatment Phase for Lead Clinical Candidate PH-762 Dose Escalation Trial is Complete with Favorable Safety, Tolerability and Pathology Data 2025 Financings and Warrant Exercises Strengthen Balance Sheet with $23.7 Million in Net Proceeds, Extending Cash Runway into the First Half of 2027 King of Prussia, Pennsylvania--(Newsfile Corp. - March 5, 2026) - Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage siRNA biopharmaceutical company developing therapeutics using its proprietary INTASYL® gene silencing technology to eliminate cancer. Phio today reported its financial results for the year ended December 31, 2025, and provided a business update. "Final cohort results mark the culmination of a productive 2025 fiscal year for Phio," said Robert Bitterman, Present and CEO. "Concluding the Phase 1b study with favorable safety, tolerability and pathology data, advancing the CMC and toxicology initiatives while extending our cash runway into 2027 are noteworthy milestones on our continuing pathway to potential approval." Recent Corporate Updates PH-762 Clinical Progress PH-762 is currently being evaluated in a U.S. multi-center Phase 1b dose-escalating clinical trial through the intratumoral injection of PH-762 for the treatment of patients with cutaneous squamous cell carcinoma, melanoma and Merkel cell carcinoma. The trial (NCT 06014086) is designed to evaluate the safety and tolerability of neoadjuvant use of intratumorally injected PH-762, assess the tumor response, and determine the dose or dose range for continued study of PH-762. The study was fully enrolled in November 2025 with a total of 22 patients, 20 with cutaneous squamous cell carcinoma, one with melanoma and one with Merkel cell carcinoma. While final study data is pending formal analysis, an FDA submission intended to propose and seek guidance for next steps in clinical study design for PH-762 is targeted for the second quarter of 2026. In July 2025, Phio entered into a comprehensive drug substance development services agreement with a US manufacturer. The manufacturer will provide analytical and process development and cGMP manufacture of Phio's lead development compound PH-762. The cGMP material will support future pivotal clinical development of PH-762. In December 2025, Phio entered into a development services agreement with a US laboratory to conduct a non-clinical toxicology study, which is required by the FDA prior to commencing a pivotal human clinical trial for registration purposes. Capital Sourcing During 2025, Phio strengthened its balance sheet through a series of equity financings and warrant exercises that generated approximately $23.7 million in net proceeds. These transactions extended the Company's cash runway into the first half of 2027 and will support ongoing clinical development, operational requirements and strategic initiatives. Patent Portfolio Enhancement and Rationalization Phio's patent portfolio includes 54 issued patents, 49 of which cover our INTASYL platform, and of those 27 cover immuno-oncology compounds and therapeutic uses. There are 20 pending patent applications, encompassing what we believe to be important new RNAi compounds and their use as therapeutics, chemical modifications of RNAi compounds that improve the compounds suitability for therapeutic uses and compounds directed to specific targets. The patents that may issue from these pending applications will, if issued, be set to expire between 2029 and 2044. Scientific News During 2025, Phio presented new data on PH-762 at several conferences including American Academy of Cancer Research (AACR), Society for Immunotherapy of Cancer (SITC), American Society of Gene and Cell Therapy (ASGCT), and at the Annual Oligonucleotide Therapeutics Society (OTS). The Company was also invited to present its Phase 1b clinical trial data for PH-762 at the American Academy of Dermatology (AAD) in the Late-Breaking Research Session. Financial Results Cash Position At December 31, 2025, the Company had cash and cash equivalents of approximately $21.0 million as compared with approximately $5.4 million at December 31, 2024. During the year ended December 31, 2025, we completed multiple financings generating total net proceeds of approximately $20.6 million after deducting placement agent fees and offering expenses. Research and Development Expenses Research and development expenses for the year ended December 31, 2025 increased 27% as compared with the year ended December 31, 2024. The increase was due to the advancement of our PH-762 clinical program, planning for an upcoming PH-762 toxicology study and higher employee compensation costs. General and Administrative Expenses General and administrative expenses for the year ended December 31, 2025 increased 23% as compared to the year ended December 31, 2024. The increase was due to higher outsourced professional accounting and legal services and stock-based compensation costs. Net Loss Net loss was approximately $8.7 million, or ($1.45) per share, for the year ended December 31, 2025 as compared with a net loss of approximately $7.2 million, or ($9.08) per share, for the year ended December 31, 2024. The increase in net loss was primarily due to the changes in research and development and general and administrative expenses, as described above. About Phio Pharmaceuticals Corp. Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage biopharmaceutical company advancing its proprietary INTASYL® siRNA gene silencing technology to eliminate cancer. Phio's INTASYL compounds are designed to enhance the body's immune cells to more effectively kill cancer cells. Phio's lead clinical development program is an INTASYL compound, PH-762, that silences the PD-1 gene implicated in various forms of skin cancer. The Phase 1b trial (NCT# 06014086) is evaluating PH-762 for the treatment of cutaneous squamous cell carcinoma, melanoma and Merkel cell carcinoma. PH-762 is a potential non-surgical treatment for skin cancers. For additional information, visit the Company's website, www.phiopharma.com. Forward-Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words such as "intends," "believes," "anticipates," "indicates," "plans," "expects," "suggests," "may," "would," "should," "potential," "designed to," "will," "ongoing," "estimate," "forecast," "target," "predict," "could" and similar references, although not all forward-looking statements contain these words. These statements, which include statements regarding the anticipated benefits of our INTASYL™ RNAi platform, the results from our ongoing clinical trials, our expectations that our cash runway will extend into the first half of 2027, our expectations regarding timing of FDA submissions intended to propose and seek guidance for next steps in clinical study design for PH-762, details regarding our planned non-clinical toxicology study, and our ability to support ongoing clinical development, operational requirements and strategic initiatives with the capital we currently have on hand, are based only on our current beliefs, expectations and assumptions and are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict and many of which are outside of our control. Our actual results may differ materially from those indicated in the forward-looking statements as a result of a number of important factors, including, but not limited to, the impact to our business and operations by inflationary pressures, rising interest rates, recession fears, the development of our product candidates, results from our preclinical and clinical activities, our ability to execute on business strategies, our ability to develop our product candidates with collaboration partners, and the success of any such collaborations, the timeline and duration for advancing our product candidates into clinical development, the timing or likelihood of regulatory filings and approvals, the success of our efforts to commercialize our product candidates if approved, our ability to manufacture and supply our product candidates for clinical activities, and for commercial use if approved, the scope of protection we are able to establish and maintain for intellectual property rights covering our technology platform, our ability to obtain future financing, market and other conditions and those risks identified in our Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q under the caption "Risk Factors" and in other filings the Company periodically makes with the SEC. Readers are urged to review these risk factors and to not act in reliance on any forward-looking statements, as actual results may differ from those contemplated by our forward-looking statements. Phio does not undertake to update forward-looking statements to reflect a change in its views, events or circumstances that occur after the date of this release, except as required by law. Contact: Phio Pharmaceuticals Corp. Jennifer Phillips: [email protected] Corporate Affairs PHIO PHARMACEUTICALS CORP. CONSOLIDATED STATEMENTS OF OPERATIONS (Amounts in thousands, except share and per share data) PHIO PHARMACEUTICALS CORP. CONSOLIDATED BALANCE SHEETS (Amounts in thousands, except share data) To view the source version of this press release, please visit https://www.newsfilecorp.com/release/286264

Clinical Trial has Advanced to Fifth and Final Cohort at Maximum Dose of INSTASYL PH-762 in Skin Cancer Trial Positive Pathology Results at Maximum Dose: 100% Tumor Clearance (Complete Response) in One Patient, Greater than 90% (Near Complete Response) in Second Patient, Greater than 50% (Partial Response) in Third Patient Safety Monitoring Committee Issues Favorable Review of Safety Data at Maximum Dose of INTASYL PH-762 Warrant Inducement Financing in November 2025 for Expected Net Proceeds Totaling Approximately $12.1 million, Extending Cash Runway into the First Half of 2027 King of Prussia, Pennsylvania--(Newsfile Corp. - November 13, 2025) - Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage biopharmaceutical company developing therapeutics using its proprietary INTASYL® siRNA gene silencing technology to eliminate cancer. Phio today reported its financial results for the quarter ended September 30, 2025 and provided a business update. Recent Corporate Updates PH-762 Clinical Progress Phio's ongoing Phase 1b dose escalation clinical trial (NCT 06014086) is designed to evaluate the safety and tolerability of neoadjuvant use of intratumoral PH-762 in Stages 1, 2 and 4 cutaneous squamous cell carcinoma (cSCC), Stage 4 melanoma, and Stage 4 Merkel cell carcinoma. Per the trial's protocol, patients receive four injections of PH-762 at weekly intervals and pathologic response is assessed on day 36 after the initial injection of PH-762. To date, pathologic results for the fifth and final cohort were as follows: 100% tumor clearance in one of three patients, > 90% clearance in the second patient, and > 50% clearance in the third patient at Day 36. To date, a total of 18 patients with cutaneous carcinomas have completed treatment across five dose escalating cohorts in the Phase 1b trial. The cumulative pathologic response in 16 patients with cSCC include six with a complete response (100% clearance), two with a near complete response (> 90% clearance) and two with a partial response (> 50% clearance). A single patient with metastatic Merkel cell carcinoma had a partial response (> 50% clearance). Six patients with cSCC and one patient with metastatic melanoma had a pathologic non-response (< 50% clearance). No patients in the study, however, exhibited clinical progression of disease. To date, there were no dose-limiting toxicities or clinically relevant treatment-emergent adverse effects in the patients receiving intratumoral PH-762 in this trial. Moreover, PH-762 has been well tolerated in all enrolled patients in each escalating dose cohort. Phio may continue to screen and treat additional patients as part of the fifth cohort. In July 2025, the Company entered into a comprehensive drug substance development services agreement with a U.S. manufacturing company pursuant to which the manufacturer will provide analytical and process development and cGMP manufacture of clinical supplies for Phio's lead development compound, PH-762. Scientific and Investor Presentations In September 2025, Phio delivered podium presentations for its INTASYL self-delivering siRNA technology at the Wainwright Global Investment Conference and the Life Sciences PA Life Sciences Future Conference. The Company presented its Phase 1b clinical trial results to date. The Company also delivered virtual presentations on its INTASYL compounds PH-762 and PH-894 in October 2025 at the Renmark Video Non Deal Roadshow. A poster highlighting an update on the ongoing clinical study for PH-762 was presented at the Society for Immunotherapy of Cancer (SITC) meeting in National Harbor, MD. In addition, a podium presentation entitled "Synthesized INTASYL siRNA Technology Downregulating Gene Expression" will be held at the Advanced Therapies USA conference 2025 in Philadelphia, PA. Warrant Inducements On July 25, 2025, the Company entered into warrant inducement agreements with certain holders of certain of the Company's existing common stock warrants to exercise such warrants for an aggregate of 928,596 shares of the Company's common stock. In consideration for the exercise of such warrants and the payment of an additional $0.125 per new warrant, the Company agreed to issue to such holders new unregistered common stock warrants to purchase an aggregate of up to 1,857,192 shares of common stock with an exercise price of $2.485 per share. In connection with this financing, the Company raised approximately $2.1 million after expenses. On November 3, 2025, the Company entered into warrant inducement agreements with certain holders of certain of the Company's existing common stock warrants to exercise such warrants for an aggregate of 5,663,182 shares of the Company's common stock. In consideration for the exercise of such warrants and the payment of an additional $0.125 per new warrant, the Company agreed to issue to such holders new unregistered common stock warrants to purchase an aggregate of up to 11,326,364 shares of common stock with an exercise price of $2.05 per share. In connection with this financing, the Company expects to raise approximately $12.1 million, of which $11.5 million has been received by the Company, with the remainder expected by November 18, 2025. Third Quarter 2025 Financial Results Cash Position At September 30, 2025, the Company had cash and cash equivalents of approximately $10.7 million as compared with approximately $5.4 million at December 31, 2024. As of the date of this release, the Company had estimated cash and cash equivalents of approximately $21.3 million, which is projected to sustain operations into first half of 2027. Research and Development Expenses Research and development expenses for the three months ended September 30, 2025 were $1.2 million compared to $0.6 million for the same period in 2024. The increase in research and development expenses was primarily driven by higher clinical trial costs and chemistry, manufacturing and controls (CMC) costs in connection with advancing our PH-762 program, as well as an increase in R&D employee personnel-related costs. General and Administrative Expenses General and administrative expenses for the three months ended September 30, 2025 were $1.3 million compared to $0.9 million for the same period in 2024. The increase in general and administrative expenses was primarily driven by an increase in outsourced professional fees related to accounting and legal services as well as employee stock compensation expense. Net Loss Net loss was $2.4 million for the three months ended September 30, 2025 compared with $1.5 million for the same period in 2024. The increase in net loss was due to the changes in research and development and general and administrative expenses as described above. About Phio Pharmaceuticals Corp. Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage siRNA biopharmaceutical company advancing its INTASYL® gene silencing technology focused on immuno-oncology therapeutics. Phio's INTASYL compounds are designed to enhance the body's immune cells to more effectively kill cancer cells. Phio's lead clinical program is an INTASYL compound, PH-762, that silences the PD-1 gene implicated in various forms of skin cancer. The ongoing Phase 1b trial (NCT# 06014086) is evaluating PH-762 for the treatment of cutaneous squamous cell carcinoma, melanoma, and Merkel cell carcinoma. PH-762 is a potential non-surgical treatment for skin cancers. For additional information, visit the Company's website, www.phiopharma.com. Forward Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words such as "intends," "believes," "anticipates," "indicates," "plans," "expects," "suggests," "may," "would," "should," "potential," "designed to," "will," "ongoing," "estimate," "forecast," "target," "predict," "could" and similar references, although not all forward-looking statements contain these words. Examples of forward-looking statements contained in this press release include, among others, the possibility that our INTASYL® siRNA gene silencing technology will make the body's immune cells more effective in killing cancer cells, the potential for PH-762 to present a viable non-surgical alternative for skin cancer, expectations regarding timing of enrollment, the expectations that we have sufficient capital to complete the treatment phase of our ongoing Phase 1b clinical trial, our expected cash runway, and statements regarding our clinical strategy, development plans and timelines and other future events. These statements are based only on our current beliefs, expectations and assumptions and are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict and many of which are outside of our control. Our actual results may differ materially from those indicated in the forward-looking statements as a result of a number of important factors, including, but not limited to, results from our preclinical and clinical activities, our ability to execute on business strategies, the timing or likelihood of regulatory filings and approvals, our ability to manufacture and supply our product candidates for clinical activities, and for commercial use if approved, the scope of protection we are able to establish and maintain for intellectual property rights covering our technology platform, our ability to obtain future financing, market and other conditions and those identified in our Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q under the caption "Risk Factors" and in other filings the Company periodically makes with the SEC. Readers are urged to review these risk factors and to not act in reliance on any forward-looking statements, as actual results may differ from those contemplated by our forward-looking statements. Phio does not undertake to update forward-looking statements to reflect a change in its views, events or circumstances that occur after the date of this release, except as required by law. Contact: Phio Pharmaceuticals Corp. Jennifer Phillips: [email protected] Corporate Affairs PHIO PHARMACEUTICALS CORP. CONSOLIDATED STATEMENTS OF OPERATIONS (Amounts in thousands, except share and per share data) (Unaudited) PHIO PHARMACEUTICALS CORP. CONDENSED CONSOLIDATED BALANCE SHEETS (Amounts in thousands, except share and per share data) (Unaudited) To view the source version of this press release, please visit https://www.newsfilecorp.com/release/274265

Poster Presentation at the 40th Annual Meeting of the Society for Immunotherapy of Cancer (SITC) King of Prussia, Pennsylvania--(Newsfile Corp. - November 7, 2025) - Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage siRNA biopharmaceutical company developing therapeutics using its proprietary INTASYL® gene silencing technology to eliminate cancer. Phio announced today that it will present clinical data from its ongoing Phase 1b clinical trial at the 40th Annual Meeting of the Society for Immunotherapy of Cancer (SITC), which will be held in National Harbor, Maryland from November 7-9, 2025. Phio's poster presentation will highlight the clinical results from the ongoing Phase 1b dose escalation clinical trial. This clinical trial is designed to evaluate the safety and tolerability of intratumoral injection of PH-762 in patients with cutaneous squamous carcinoma, Merkel cell carcinoma, and melanoma. Presentation Details are as follows: About Phio Pharmaceuticals Corp. Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage siRNA biopharmaceutical company advancing its INTASYL® gene silencing technology focused on immuno-oncology therapeutics. Phio's INTASYL compounds are designed to enhance the body's immune cells to more effectively kill cancer cells. Phio's lead clinical program is an INTASYL compound, PH-762, that silences the PD-1 gene implicated in various forms of skin cancer. The ongoing Phase 1b trial (NCT# 06014086) is evaluating PH-762 for the treatment of cutaneous squamous cell carcinoma, melanoma, and Merkel cell carcinoma. PH-762 is a potential non-surgical treatment for skin cancers. For additional information, visit the Company's website, www.phiopharma.com. Forward-Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words such as "intends," "believes," "anticipates," "indicates," "plans," "expects," "suggests," "may," "would," "should," "potential," "designed to," "will," "ongoing," "estimate," "forecast," "target," "predict," "could" and similar references, although not all forward-looking statements contain these words. Examples of forward-looking statements contained in this press release include, among others, the possibility that our INTASYL® siRNA gene silencing technology will make the body's immune cells more effective in killing cancer cells, our expectations with respect to the continued safety results of our clinical trial, our expectations with respect to the potential of a well-tolerated treatment for cutaneous carcinomas, and statements regarding our commercial and clinical strategy, development plans and timelines and other future events. These statements are based only on our current beliefs, expectations and assumptions and are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict and many of which are outside of our control. Our actual results may differ materially from those indicated in the forward-looking statements as a result of a number of important factors, including, but not limited to, the impact to our business and operations by inflationary pressures, rising interest rates, recession fears, the development of our product candidates, results from our preclinical and clinical activities, our ability to execute on business strategies, our ability to develop our product candidates with collaboration partners, and the success of any such collaborations, the timeline and duration for advancing our product candidates into clinical development, the timing or likelihood of regulatory filings and approvals, the success of our efforts to commercialize our product candidates if approved, our ability to manufacture and supply our product candidates for clinical activities, and for commercial use if approved, the scope of protection we are able to establish and maintain for intellectual property rights covering our technology platform, our ability to obtain future financing, market and other conditions and those identified in our Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q under the caption "Risk Factors" and in other filings the Company periodically makes with the SEC. Readers are urged to review these risk factors and to not act in reliance on any forward-looking statements, as actual results may differ from those contemplated by our forward-looking statements. Phio does not undertake to update forward-looking statements to reflect a change in its views, events or circumstances that occur after the date of this release, except as required by law. Contact: Phio Pharmaceuticals Corp. Jennifer Phillips: [email protected] Corporate Affairs To view the source version of this press release, please visit https://www.newsfilecorp.com/release/273523

Pathologic Clearance: 100% Tumor Clearance (Complete Response) in One Patient, Greater than 90% (Near Complete Response) in Second Patient, Greater than 50% (Partial Response) in Third Patient Pathologic Results Assessed at Approximately 5 Weeks Safety Monitoring Committee Issues Favorable Review of Safety Data at the Maximum Dose King of Prussia, Pennsylvania--(Newsfile Corp. - November 3, 2025) - Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage siRNA biopharmaceutical company developing therapeutics using its proprietary INTASYL® gene silencing technology to eliminate cancer. Phio announced today the pathologic results for three patients with cutaneous squamous cell carcinoma (cSCC) who completed treatment in the fifth and final dose cohort of Phio's on-going Phase 1b dose escalation trial: 100% tumor clearance in one of three patients, > 90% clearance in the second patient, and > 50% clearance in the third patient. To date, a total of 18 patients with cutaneous carcinomas have completed treatment across five dose escalating cohorts in the Phase 1b trial. The cumulative pathologic response in 16 patients with cSCC include six with a complete response (100% clearance), two with a near complete response (> 90% clearance) and two with a partial response (> 50% clearance). A single patient with metastatic Merkel cell carcinoma had a partial response (> 50% clearance). Six patients with cSCC and one patient with metastatic melanoma had a pathologic non-response (< 50% clearance). No patients in the study have exhibited clinical progression of disease. Phio may continue to screen and treat additional patients as part of the fifth cohort. The trial is designed to evaluate the safety and tolerability of neoadjuvant use of intratumoral PH-762 in Stages 1, 2 and 4 cutaneous squamous cell carcinoma (cSCC), Stage 4 melanoma, and Stage 4 Merkel cell carcinoma (NCT# 06014086). Per the trial's protocol, patients receive four injections of PH-762 at weekly intervals and pathologic response is assessed approximately 5 weeks after the initial injection of PH-762. "The encouraging outcomes of intratumoral PH-762 in patients who have received treatment thus far is a significant step in clinical development and highlights the promise of a viable non-surgical alternative treatment for cutaneous carcinomas," said Robert Bitterman, CEO and Chairman of Phio Pharmaceuticals. In addition, the Safety Monitoring Committee (SMC) completed its pre-specified review of safety results for the first three patients in the fifth cohort and confirmed that there were no dose-limiting toxicities or clinically relevant treatment-emergent adverse effects at this maximum dose concentration. Further, there have been no dose-limiting toxicities or clinically relevant treatment-emergent adverse effects in any of the patients who have completed treatment with intratumoral PH-762 in this trial. "We are pleased with the continuing safety profile of PH-762 throughout dose escalation to approximately a 20-fold increase versus that received in the first cohort," said Mary Spellman, MD, Phio's acting Chief Medical Officer. "PH-762 has been well tolerated in this trial, without relevant immune-related adverse events or other toxicities." About Phio Pharmaceuticals Corp. Phio Pharmaceuticals Corp. (Nasdaq: PHIO) is a clinical-stage siRNA biopharmaceutical company advancing its INTASYL® gene silencing technology focused on immuno-oncology therapeutics. Phio's INTASYL compounds are designed to enhance the body's immune cells to more effectively kill cancer cells. Phio's lead clinical program is an INTASYL compound, PH-762, that silences the PD-1 gene implicated in various forms of skin cancer. The on-going Phase 1b trial (NCT# 06014086) is evaluating PH-762 for the treatment of cutaneous squamous cell carcinoma, melanoma and Merkel cell carcinoma. PH-762 is a potential non-surgical treatment for skin cancers. For additional information, visit the Company's website, www.phiopharma.com. Forward Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words such as "intends," "believes," "anticipates," "indicates," "plans," "expects," "suggests," "may," "would," "should," "potential," "designed to," "will," "ongoing," "estimate," "forecast," "target," "predict," "could" and similar references, although not all forward-looking statements contain these words. Examples of forward-looking statements contained in this press release include, among others, the possibility that our INTASYL® siRNA gene silencing technology will make the body's immune cells more effective in killing cancer cells, our expectations with respect to the continued safety results of our clinical trial, our expectations with respect to the potential of a viable non-surgical alternative treatment for cutaneous carcinomas, and statements regarding our commercial and clinical strategy, development plans and timelines and other future events. These statements are based only on our current beliefs, expectations and assumptions and are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict and many of which are outside of our control. Our actual results may differ materially from those indicated in the forward-looking statements as a result of a number of important factors, including, but not limited to, the impact to our business and operations by inflationary pressures, rising interest rates, recession fears, the development of our product candidates, results from our preclinical and clinical activities, our ability to execute on business strategies, our ability to develop our product candidates with collaboration partners, and the success of any such collaborations, the timeline and duration for advancing our product candidates into clinical development, the timing or likelihood of regulatory filings and approvals, the success of our efforts to commercialize our product candidates if approved, our ability to manufacture and supply our product candidates for clinical activities, and for commercial use if approved, the scope of protection we are able to establish and maintain for intellectual property rights covering our technology platform, our ability to obtain future financing, market and other conditions and those identified in our Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q under the caption "Risk Factors" and in other filings the Company periodically makes with the SEC. Readers are urged to review these risk factors and to not act in reliance on any forward-looking statements, as actual results may differ from those contemplated by our forward-looking statements. Phio does not undertake to update forward-looking statements to reflect a change in its views, events or circumstances that occur after the date of this release, except as required by law. Contact: Phio Pharmaceuticals Corp. Jennifer Phillips: [email protected] Corporate Affairs To view the source version of this press release, please visit https://www.newsfilecorp.com/release/272749

Clinical trial advances for INSTASYL siRNA lead product candidate PH-762 5th cohort enrolling patients in on-going clinical study King of Prussia, Pennsylvania--(Newsfile Corp. - August 14, 2025) - Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage biopharmaceutical company developing therapeutics using its proprietary INTASYL® siRNA gene silencing technology to eliminate cancer. Phio today reported its financial results for the quarter ended June 30, 2025 and provided a business update. Recent Corporate Updates PH-762 Clinical Progress Phio's ongoing Phase 1b dose escalation clinical trial (NCT 06014086) is designed to evaluate the safety and tolerability of neoadjuvant use of intratumoral PH-762 in Stages 1, 2 and 4 cutaneous squamous cell carcinoma (cSCC), Stage 4 melanoma, and Stage 4 Merkel cell carcinoma. To date, a total of 15 patients with cutaneous carcinomas have been treated across four cohorts in the Phase 1b trial. These cohorts included 13 patients with cSCC, one patient with metastatic melanoma and one patient with metastatic Merkel cell carcinoma. There have been no dose-limiting toxicities or clinically relevant treatment-emergent adverse effects in the patients who received intratumoral PH-762 in this trial. Moreover, PH-762 has been well tolerated in all enrolled patients in each escalating dose cohort. No patients exhibited clinical progression of disease during the treatment phase of this trial. The cumulative pathologic responses in the 13 patients with cSCC include five with complete response (100% clearance), one patient with a near complete response (>90% clearance), one with a partial response (>50% clearance) and six patients with a pathologic non-response (< 50% clearance). The Merkel cell carcinoma patient with stage 4 metastatic disease had a pathological partial response (>50% clearance). The melanoma patient was a non-responder (<50% clearance). Phio is now enrolling what is expected to be the 5th and final cohort in the Phase 1b trial. In addition, the Company entered into a comprehensive drug substance development services agreement with a U.S. manufacturing company. The company will provide analytical and process development and cGMP manufacture of Phio's lead development compound PH-762. Scientific News In May 2025, Phio delivered a podium presentation for its INTASYL self-delivering siRNA technology at the Society of Investigative Dermatology (SID). The Company presented its Phase 1b clinical trial results to date. The Company also delivered podium presentations on its INTASYL compounds PH-762 and PH-894 in April 2025 at the 11th Annual Immunotherapy of Cancer (ITOC 11) conference in Munich, Germany. In June 2025, Phio presented interim data on its Phase 1b clinical trial at the American Society of Clinical Oncology (ASCO) conference. Subsequent Events On July 25, 2025, the Company entered into warrant inducement agreements with certain holders of the Company's existing warrants to purchase an aggregate of 928,596 shares of common stock in connection with the exercise of common stock warrants issued between December 2024 and January 2025 with exercise prices between $2.00 and $2.485 per share. In connection with this financing, the Company raised approximately $2.2 million after expenses. Financial Results Cash Position At June 30, 2025, the Company had cash and cash equivalents of approximately $10.8 million as compared with approximately $5.4 million at December 31, 2024. Research and Development Expenses Research and development expenses for the three months ended June 30, 2025 were $1.1 million compared to $0.9 million for the same period in 2024. The increase in research and development expenses was primarily driven by higher CRO pass-through costs associated with increased patient enrollment, as well as higher consulting and salary-related costs. Research and development expenses for the six months ended June 30, 2025 were $1.9 million compared to $2.0 million for the same period in 2024. The fluctuation was immaterial and within expected operating ranges. General and Administrative Expenses General and administrative expenses for the three months ended June 30, 2025 were $1.2 million compared to $1.0 million for the same period in 2024. The increase in general and administrative expenses was primarily driven by an increase in salary-related costs. General and administrative expenses for the six months ended June 30, 2025 were $2.2 million compared to $1.8 million for the same period in 2024. The increase in general and administrative expenses was primarily driven by an increase in salary-related costs. Net Loss Net loss was $2.2 million for the three months ended June 30, 2025 compared with $1.8 million for the same period in 2024. The increase in net loss was due to the changes in research and development and general and administrative expenses as described above. About Phio Pharmaceuticals Corp. Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage siRNA biopharmaceutical company advancing its INTASYL® gene silencing technology focused on immuno-oncology therapeutics. Phio's INTASYL compounds are designed to enhance the body's immune cells to more effectively kill cancer cells. Phio's lead clinical program is an INTASYL compound, PH-762, that silences the PD-1 gene implicated in various forms of skin cancer. The on-going Phase 1b trial (NCT# 06014086) is evaluating PH-762 for the treatment of cutaneous squamous cell carcinoma, melanoma, and Merkel cell carcinoma. PH-762 is a potential non-surgical treatment for skin cancers. For additional information, visit the Company's website, www.phiopharma.com. Forward Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words such as "intends," "believes," "anticipates," "indicates," "plans," "expects," "suggests," "may," "would," "should," "potential," "designed to," "will," "ongoing," "estimate," "forecast," "target," "predict," "could" and similar references, although not all forward-looking statements contain these words. Examples of forward-looking statements contained in this press release include, among others, the possibility that our INTASYL® siRNA gene silencing technology will make the body's immune cells more effective in killing cancer cells, the potential for PH-762 to present a viable non-surgical alternative for skin cancer, expectations regarding timing of enrollment, the expectations that we have sufficient capital to complete the treatment phase of our ongoing Phase 1b clinical trial, and statements regarding our clinical strategy, development plans and timelines and other future events.    These statements are based only on our current beliefs, expectations and assumptions and are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict and many of which are outside of our control.  Our actual results may differ materially from those indicated in the forward-looking statements as a result of a number of important factors, including, but not limited to, results from our preclinical and clinical activities, our ability to execute on business strategies, the timing or likelihood of regulatory filings and approvals, our ability to manufacture and supply our product candidates for clinical activities, and for commercial use if approved, the scope of protection we are able to establish and maintain for intellectual property rights covering our technology platform, our ability to obtain future financing, market and other conditions and those identified in our Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q under the caption "Risk Factors" and in other filings the Company periodically makes with the SEC. Readers are urged to review these risk factors and to not act in reliance on any forward-looking statements, as actual results may differ from those contemplated by our forward-looking statements. Phio does not undertake to update forward-looking statements to reflect a change in its views, events or circumstances that occur after the date of this release, except as required by law.   Contact: Phio Pharmaceuticals Corp. Jennifer Phillips: [email protected] Corporate Affairs PHIO PHARMACEUTICALS CORP. CONSOLIDATED STATEMENTS OF OPERATIONS (Amounts in thousands, except share and per share data) (Unaudited) PHIO PHARMACEUTICALS CORP. CONDENSED CONSOLIDATED BALANCE SHEETS (Amounts in thousands, except share and per share data) To view the source version of this press release, please visit https://www.newsfilecorp.com/release/262496

Complete Pathologic Response in patient with cutaneous squamous cell carcinoma Partial Response in Stage 4 metastatic Merkel cell patient King of Prussia, Pennsylvania--(Newsfile Corp. - July 25, 2025) - Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage siRNA biopharmaceutical company developing therapeutics using its proprietary INTASYL® gene silencing technology to eliminate cancer. Phio announced today that pathologic results are available for four of the five patients treated in the fourth cohort. A complete pathologic response (100% tumor clearance) has been reported for one patient with cutaneous squamous cell carcinoma (cSCC). One patient with metastatic Merkel cell carcinoma was reported as a partial response (> 50% clearance). Two patients with cSCC were reported as having a pathologic non-response (<50% tumor clearance). Pathologic results for the remaining patient with cSCC are still pending. Phio's ongoing Phase 1b dose escalation clinical trial (NCT 06014086) is designed to evaluate the safety and tolerability of neoadjuvant use of intratumoral PH-762 in Stages 1, 2 and 4 cSCC, Stage 4 melanoma, and Stage 4 Merkel cell carcinoma. To date, a total of 15 patients with cutaneous carcinomas have been treated across the four cohorts. There were no dose-limiting toxicities or clinically relevant treatment-emergent adverse effects in the patients receiving intratumoral PH-762 in this trial. Moreover, PH-762 has been well tolerated in all enrolled patients in each escalating dose cohort. No patients exhibited clinical progression of disease. The cumulative pathologic response in 13 patients with cSCC include five complete response (100% clearance), one patient with a near complete response (>90% clearance) and one with a partial response (>50% clearance) and six patients with a pathologic non-response (< 50% clearance). The one Merkel cell carcinoma patient with stage 4 metastatic disease had a partial response (>50% clearance). The melanoma patient was a non-responder (<50% clearance). Phio is now enrolling what is expected to be the 5th and final cohort in the Phase 1b study. "The positive safety and efficacy outcomes through the fourth cohort continue to indicate that PH-762 may present a viable non-surgical alternative in this large and continually expanding skin cancer market," said Robert Bitterman, CEO and Chairman of Phio Pharmaceuticals. About Phio Pharmaceuticals Corp. Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage siRNA biopharmaceutical company advancing its INTASYL® gene silencing technology focused on immuno-oncology therapeutics. Phio's INTASYL compounds are designed to enhance the body's immune cells to more effectively kill cancer cells. Phio's lead clinical program is an INTASYL compound, PH-762, that silences the PD-1 gene implicated in various forms of skin cancer. The on-going Phase 1b trial (NCT# 06014086) is evaluating PH-762 for the treatment of cutaneous squamous cell carcinoma, melanoma and Merkel cell carcinoma. PH-762 is a potential non-surgical treatment for skin cancers. For additional information, visit the Company's website, www.phiopharma.com. Forward-Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words such as "intends," "believes," "anticipates," "indicates," "plans," "expects," "suggests," "may," "would," "should," "potential," "designed to," "will," "ongoing," "estimate," "forecast," "target," "predict," "could" and similar references, although not all forward-looking statements contain these words. Examples of forward-looking statements contained in this press release include, among others, the possibility that our INTASYL® siRNA gene silencing technology will make the body's immune cells more effective in killing cancer cells and statements regarding our commercial and clinical strategy, development plans and timelines and other future events. These statements are based only on our current beliefs, expectations and assumptions and are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict and many of which are outside of our control. Our actual results may differ materially from those indicated in the forward-looking statements as a result of a number of important factors, including, but not limited to, the impact to our business and operations by inflationary pressures, rising interest rates, recession fears, the development of our product candidates, results from our preclinical and clinical activities, our ability to execute on business strategies, our ability to develop our product candidates with collaboration partners, and the success of any such collaborations, the timeline and duration for advancing our product candidates into clinical development, the timing or likelihood of regulatory filings and approvals, the success of our efforts to commercialize our product candidates if approved, our ability to manufacture and supply our product candidates for clinical activities, and for commercial use if approved, the scope of protection we are able to establish and maintain for intellectual property rights covering our technology platform, our ability to obtain future financing, market and other conditions and those identified in our Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q under the caption "Risk Factors" and in other filings the Company periodically makes with the SEC. Readers are urged to review these risk factors and to not act in reliance on any forward-looking statements, as actual results may differ from those contemplated by our forward-looking statements. Phio does not undertake to update forward-looking statements to reflect a change in its views, events or circumstances that occur after the date of this release, except as required by law. Contact: Phio Pharmaceuticals Corp. Jennifer Phillips: [email protected] Corporate Affairs To view the source version of this press release, please visit https://www.newsfilecorp.com/release/260122

Clinical trial advances for INSTASYL siRNA lead product candidate PH-762 4th Cohort enrolling and treating patients in on-going clinical study Marlborough, Massachusetts--(Newsfile Corp. - May 15, 2025) - Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage biopharmaceutical company developing therapeutics that use its INTASYL® siRNA gene silencing technology designed to make the body's immune cells more effective in killing cancer cells. Phio today reported its financial results for the quarter ended March 31, 2025 and provided a business update. Recent Corporate Updates PH-762 Clinical Progress Phio's ongoing Phase 1b dose escalation clinical trial (NCT 06014086) is designed to evaluate the safety and tolerability of neoadjuvant use of intratumoral PH-762 in Stages 1, 2 and 4 cutaneous squamous cell carcinoma (cSCC), Stage 4 melanoma, and Stage 4 Merkel cell carcinoma. To date, a total of 10 patients with cutaneous carcinomas have been treated in Cohorts 1, 2 and 3. These cohorts included 9 patients with cSCC and 1 patient with metastatic melanoma. At Day 36 (planned tumor excision), of the 9 patients with cSCC, 4 patients had a pathologic complete response (100% tumor clearance). One patient had a near complete response (>90% clearance) and 1 patient had a partial response (>50% clearance). The other 3 cSCC and one metastatic melanoma patient had a pathologic non-response (< 50% clearance). Patients with a pathologic complete response (100% tumor clearance) may have visual signs of residual scar or subdermal inflammation prior to resection. No patients, however, exhibited clinical progression of disease. To date, there were no dose-limiting toxicities or clinically relevant treatment-emergent adverse effects in the patients receiving intratumoral PH-762 in this trial. Moreover, PH-762 has been well tolerated in all enrolled patients in each escalating dose cohort. The fourth cohort is currently enrolling and treating patients; Phio expects to complete enrollment in the trial in the third quarter of 2025. Scientific News During the three months ended March 31, 2025, Phio was awarded podium presentations for its INTASYL self-delivering siRNA technology at the American Academy of Dermatology (AAD) and at the Society of Investigative Dermatology (SID). The Company presented its phase 1b clinical trial results to date. The Company also presented data on INTASYL compounds PH-762 and PH-894 at the 11th Annual Immunotherapy of Cancer (ITOC 11) conference in Munich, Germany. The Company's INTASYL compound RXI-231 was highlighted in the peer reviewed journal, Clinical, Cosmetic and Investigational Dermatology. The article presented proof-of-concept data for RXI-231, an INTASYL compound designed to target and reduce tyrosinase (TYR) gene expression. While further characterization and clinical testing is needed, RXI-231 shows promise in treating hyperpigmentation disorders. Capital Sourcing In December 2024 and January 2025, Phio raised an aggregate of approximately $9.2 million in registered direct offerings and concurrent private placements, before deduction of commissions and other expenses. Additional gross proceeds of approximately $2.9 million were raised from the exercise of warrants previously issued on July 12, 2024. With these proceeds, the Company now believes it has sufficient capital to complete the treatment phase of the Phase 1b trial. Cost Rationalization From April 2014 to March 2024, the Company leased space that was utilized as its corporate headquarters and primary laboratory. The lease expired on March 31, 2024. On March 1, 2024, the Company commenced a lease for a laboratory facility located at 17 Briden Street, Worcester, Massachusetts. The lease had an original expiration date of August 31, 2024, and was subsequently extended through February 28, 2025. The Company continues to lease the space on a month-to-month basis. Monthly rent is approximately $2,500. In March 2025, the Company contracted with LifeSciences PA located at 411 Swedeland Road, King of Prussia, PA 19406 for access to full working space for normal hours of operations at a fee of $300 per month, which can be cancelled at any time. In May 2024, the Company terminated the Clinical Co-Development Agreement with AgonOx, Inc. (AgonOx) effective immediately. The Company paid AgonOx all payment obligations that accrued prior to the termination of the Clinical Co-Development Agreement. The Company made the remaining payment of $34,320, which primarily related to accrued obligations for patient fees and other miscellaneous costs as of the date of termination to AgonOx on March 21, 2025. This settled all future obligations to AgonOx. Financial Results Cash Position At March 31, 2025, the Company had cash of approximately $13.3 million as compared with approximately $5.4 million at December 31, 2024. Net cash provided by financing activities for the three months ended March 31, 2025 was approximately $9.2 million as compared to the three months ended March 31, 2024 where net cash used in financing activities was approximately $4,000. The increase in net cash provided by financing activities was primarily due to the issuance of common stock and warrants, and the exercise of warrants. Research and Development Expenses Research and development expenses were $0.886 million for the three months ended March 31, 2025 as compared with $1.148 million for the three months ended March 31, 2024, a decrease of 23%. The decrease in research and development expenses was primarily driven by decreases in salary-related costs and in consulting expense. General and Administrative Expenses General and administrative expenses were approximately $0.986 million for the three month period ended March 31, 2025 as compared with approximately $1.061 million for the three months ended March 31, 2024, a decrease of 7%. The Company considers this to be an immaterial fluctuation. Net Loss Net loss was $1.8 million for the three months ended March 31, 2025 as compared with $2.2 million for the three months ended March 31, 2024. The decrease in net loss was due to the reductions in research and development and general and administrative expenses cited above. About Phio Pharmaceuticals Corp. Phio Pharmaceuticals Corp. (Nasdaq: PHIO) is a clinical-stage siRNA biopharmaceutical company advancing its INTASYL® gene silencing technology focused on immuno-oncology therapeutics. Phio's INTASYL compounds are designed to enhance the body's immune cells to more effectively kill cancer cells. Phio's lead clinical program is an INTASYL compound, PH-762, that silences the PD-1 gene implicated in various forms of skin cancer. The on-going Phase 1b trial (NCT# 06014086) is evaluating PH-762 for the treatment of cutaneous squamous cell carcinoma, melanoma, and Merkel cell carcinoma. PH-762 is a potential non-surgical treatment for skin cancers. For additional information, visit the Company's website, www.phiopharma.com. Forward-Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words such as "intends," "believes," "anticipates," "indicates," "plans," "expects," "suggests," "may," "would," "should," "potential," "designed to," "will," "ongoing," "estimate," "forecast," "target," "predict," "could" and similar references, although not all forward-looking statements contain these words. Examples of forward-looking statements contained in this press release include, among others, the possibility that our INTASYL® siRNA gene silencing technology will make the body's immune cells more effective in killing cancer cells, the potential for PH-762 to present a viable non-surgical alternative for skin cancer, expectations regarding timing of enrollment, the expectations that we have sufficient capital to complete the treatment phase of our ongoing Phase 1b clinical trial, the potential for RXI-231 in treating hyperpigmentation disorders, and statements regarding our commercial and clinical strategy, development plans and timelines and other future events. These statements are based only on our current beliefs, expectations and assumptions and are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict and many of which are outside of our control. Our actual results may differ materially from those indicated in the forward-looking statements as a result of a number of important factors, including, but not limited to, the impact to our business and operations by inflationary pressures, rising interest rates, recession fears, the development of our product candidates, results from our preclinical and clinical activities, our ability to execute on business strategies, our ability to develop our product candidates with collaboration partners, and the success of any such collaborations, the timeline and duration for advancing our product candidates into clinical development, the timing or likelihood of regulatory filings and approvals, the success of our efforts to commercialize our product candidates if approved, our ability to manufacture and supply our product candidates for clinical activities, and for commercial use if approved, the scope of protection we are able to establish and maintain for intellectual property rights covering our technology platform, our ability to obtain future financing, market and other conditions and those identified in our Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q under the caption "Risk Factors" and in other filings the Company periodically makes with the SEC. Readers are urged to review these risk factors and to not act in reliance on any forward-looking statements, as actual results may differ from those contemplated by our forward-looking statements. Phio does not undertake to update forward-looking statements to reflect a change in its views, events or circumstances that occur after the date of this release, except as required by law. Contact: Phio Pharmaceuticals Corp. Jennifer Phillips: [email protected] Corporate Affairs PHIO PHARMACEUTICALS CORP. CONSOLIDATED STATEMENTS OF OPERATIONS (Amounts in thousands, except share and per share data) (Unaudited) PHIO PHARMACEUTICALS CORP. CONSOLIDATED BALANCE SHEETS (Amounts in thousands, except share and per share data) (Unaudited) To view the source version of this press release, please visit https://www.newsfilecorp.com/release/252220

Complete Pathologic Response reported in 2 patients in the Third Cohort with cutaneous squamous cell carcinoma, complementing results in prior cohort Phio to present trial results to date at a podium presentation at Society for Investigative Dermatology (SID) Annual Meeting on May 10th Marlborough, Massachusetts--(Newsfile Corp. - May 7, 2025) - Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage siRNA biopharmaceutical company developing therapeutics using its proprietary INTASYL® gene silencing technology to eliminate cancer. Phio announced today that a complete pathologic response (100% tumor clearance) has been reported for 2 of 3 patients with cutaneous squamous cell carcinoma (cSCC) treated in the third dose cohort. The third patient was reported as having a pathologic non-response (<50% tumor clearance). "These positive outcomes continue to indicate that PH-762 may present a viable non-surgical alternative in this large and continually expanding skin cancer market," said Robert Bitterman, President and CEO of Phio Pharmaceuticals. Phio's ongoing Phase 1b dose escalation clinical trial (NCT 06014086) is designed to evaluate the safety and tolerability of neoadjuvant use of intratumoral PH-762 in Stages 1, 2 and 4 cSCC, Stage 4 melanoma, and Stage 4 Merkel cell carcinoma. To date, a total of 10 patients with cutaneous carcinomas have been treated in Cohorts 1, 2 and 3. These cohorts included 9 patients with cSCC and 1 patient with metastatic melanoma. At day 36 (planned tumor excision), of the 9 patients with cSCC, 4 patients had a pathologic complete response (100% tumor clearance). One patient had a near complete response (>90% clearance) and 1 patient had a partial response (>50% clearance). The other 3 cSCC and one metastatic melanoma patient had a pathologic non-response (< 50% clearance). Patients with pathologic complete response (100% tumor clearance) may have visual signs of residual scar or subdermal inflammation prior to resection. No patients, however, exhibited clinical progression of disease. To date, there were no dose-limiting toxicities or clinically relevant treatment-emergent adverse effects in the patients receiving intratumoral PH-762 in this trial. Moreover, PH-762 has been well tolerated in all enrolled patients in each escalating dose cohort. The fourth cohort is currently enrolling patients; Phio expects to complete enrollment in the trial in the third quarter of 2025. "The continued positive pathologic responses in this clinical trial of intratumoral PH-762 for cutaneous carcinoma increases our understanding of the potential therapeutic benefit for this immunotherapy. The safety profile supports ongoing dose escalation," said Mary Spellman, MD, Phio's acting Chief Medical Officer. About Phio Pharmaceuticals Corp. Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage siRNA biopharmaceutical company advancing its INTASYL® gene silencing technology focused on immuno-oncology therapeutics. Phio's INTASYL compounds are designed to enhance the body's immune cells to more effectively kill cancer cells. Phio's lead clinical program is an INTASYL compound, PH-762, that silences the PD-1 gene implicated in various forms of skin cancer. The on-going Phase 1b clinical trial (NCT# 06014086) is evaluating PH-762 for the treatment of cutaneous squamous cell carcinoma, melanoma and Merkel cell carcinoma. PH-762 is a potential non-surgical treatment for skin cancers. For additional information, visit the Company's website, www.phiopharma.com. Forward-Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words such as "intends," "believes," "anticipates," "indicates," "plans," "expects," "suggests," "may," "would," "should," "potential," "designed to," "will," "ongoing," "estimate," "forecast," "target," "predict," "could" and similar references, although not all forward-looking statements contain these words. Examples of forward-looking statements contained in this press release include, among others, the possibility that our INTASYL® siRNA gene silencing technology will make the body's immune cells more effective in killing cancer cells, the potential for PH-762 to present a viable non-surgical alternative for skin cancer, expectations regarding timing of enrollment, and statements regarding our commercial and clinical strategy, development plans and timelines and other future events. These statements are based only on our current beliefs, expectations and assumptions and are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict and many of which are outside of our control. Our actual results may differ materially from those indicated in the forward-looking statements as a result of a number of important factors, including, but not limited to, the impact to our business and operations by inflationary pressures, rising interest rates, recession fears, the development of our product candidates, results from our preclinical and clinical activities, our ability to execute on business strategies, our ability to develop our product candidates with collaboration partners, and the success of any such collaborations, the timeline and duration for advancing our product candidates into clinical development, the timing or likelihood of regulatory filings and approvals, the success of our efforts to commercialize our product candidates if approved, our ability to manufacture and supply our product candidates for clinical activities, and for commercial use if approved, the scope of protection we are able to establish and maintain for intellectual property rights covering our technology platform, our ability to obtain future financing, market and other conditions and those identified in our Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q under the caption "Risk Factors" and in other filings the Company periodically makes with the SEC. Readers are urged to review these risk factors and to not act in reliance on any forward-looking statements, as actual results may differ from those contemplated by our forward-looking statements. Phio does not undertake to update forward-looking statements to reflect a change in its views, events or circumstances that occur after the date of this release, except as required by law. Contact: Phio Pharmaceuticals Corp. Jennifer Phillips: [email protected] To view the source version of this press release, please visit https://www.newsfilecorp.com/release/251072

Continues advancing clinical trial for INSTASYL siRNA lead product candidate PH-762 3rd Cohort now fully enrolled in on-going clinical study Marlborough, Massachusetts--(Newsfile Corp. - March 31, 2025) - Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage biotechnology company developing therapeutics that use its INTASYL® siRNA gene silencing technology designed to make the body's immune cells more effective in killing cancer cells. Phio today reported its financial results for the year ended December 31, 2024, and provided a business update. Recent Corporate Updates PH-762 Clinical Progress PH-762 is currently being evaluated in a U.S. multi-center Phase 1b dose-escalating clinical trial through the intratumoral injection of PH-762 for the treatment of patients with cutaneous squamous cell carcinoma, melanoma and Merkel cell carcinoma. The trial (NCT 06014086) is designed to evaluate the safety and tolerability of neoadjuvant use of intratumorally injected PH-762 in up to 30 patients to assess tumor response and determine the dose or dose range for continued study of PH-762 in future trials. In May and December 2024, respectively, a Safety Monitoring Committee (SMC) reviewed data from the first and second dose cohorts treated with PH-762, and in both instances recommended escalation to the next dose concentration. A total of 7 patients with cutaneous carcinomas have been enrolled in dose cohorts 1 and 2. The second cohort enrolled a total of 4 patients, all of whom were diagnosed with cutaneous squamous cell carcinoma. At Day 36 (tumor excision), a complete response (100% tumor clearance) was reported for 2 patients, a partial response (90% tumor clearance) was reported for 1 patient and 1 patient had stable disease, having not progressed. Patients in the first cohort maintained stable disease. To date, intratumoral injection of PH-762 has been well tolerated in all enrolled patients. There were no dose-limiting toxicities or clinically relevant treatment-emergent adverse effects in the patients receiving intratumoral PH-762. The third dose cohort is fully enrolled and patients in this cohort are currently in the treatment or follow-up phase of the study. Phio expects to complete enrollment of all patients in the study in the third quarter of 2025. Capital Sourcing In December 2024 and January 2025, Phio raised an aggregate of approximately $9.2 million in registered direct offerings and concurrent private placements, before deduction of commissions and other expenses. Additional gross proceeds of approximately $2.9 million were raised from the exercise of warrants previously issued on July 12, 2024. With these proceeds, the Company now believes it has sufficient capital to complete the treatment phase of the Phase 1b trial. Cost Rationalization In 2023, Phio commenced a cost rationalization program resulting from its strategy to transition from discovery research to a product development focus. In combination with headcount reductions, Phio did not renew its building lease in Marlborough, MA., the lease for which expired on March 31, 2024. The Company has established a smaller research footprint in the Massachusetts Biomedical Initiatives in Worcester, MA, where the Company leases laboratory space. Expense reductions have been redirected to funding the Phase 1b clinical trial for PH-762. In May 2024, Phio terminated its Clinical Co-Development Agreement with AgonOx, Inc. (AgonOx). The Clinical Co-Development Agreement was entered into to conduct a Phase 1 clinical trial of PH-762 in combination with Agonox's "double positive" tumor infiltrating lymphocytes (DP TIL) in patients with advanced melanoma and other advanced solid tumors. The primary trial objectives were to evaluate the safety and to study the potential for enhanced therapeutic benefit from the administration of PH-762 treated DP TIL. AgonOx had enrolled three patients. The first two patients were treated with DP TIL only, and a third patient was treated with a combination of DP TIL and PH-762. Clinical results for the single patient who received a combination of DP TIL and PH-762. Clinical results for the single patient who received a combination of DP TIL and PH-762 showed tumor size reductions of 65%, 100% and 81%, respectively, in three melanoma lesions. In assessing patient enrollment delays and the cost to continue the trial, management chose to redirect funding and focus on its self-directed phase 1b clinical trial with PH-762. Patent Portfolio Enhancement Phio's portfolio includes 77 issued patents, 69 of which cover its INTASYL technology. There are 19 patent families broadly covering both the composition and methods of use of the Company's self-delivering INTASYL technology and uses of INTASYL compounds targeting immune checkpoints for cancer therapy, cellular differentiation and metabolism targets for Adoptive Cell Therapy immunotherapies. Scientific News During 2024, Phio presented new data on its INTASYL self-delivering siRNA technology applications at several conferences including American Academy of Cancer Research (AACR), Society for Immunotherapy of Cancer (SITC), American Society of Gene and Cell Therapy (ASGCT) and at the Annual Oligonucleotide Therapeutics Society (OTS). Most recently, the Company was invited to present its phase 1b clinical trial results to date at the American Academy of Dermatology (AAD) in the Late-Breaking Research Session. The Company's INTASYL PH-804 compound was highlighted in the peer reviewed journal, Cancer Immunology, Immunotherapy in an article entitled, "INTASYL Self Delivering RNAi Decreases TIGIT Expression, Enhancing NK Cell Cytotoxicity: A Potential Application to Increase the Efficacy of NK Adoptive Cell Therapy Against Cancer", authored by M. Maxwell et al. Financial Results Cash Position At December 31, 2024, the Company had cash of approximately $5.4 million as compared with approximately $8.5 million at December 31, 2023. During the year ended December 31, 2024, the Company completed multiple financings and received total net proceeds of approximately $4.0 million after deducting placement agent fees and offering expenses. Subsequent to year-end, the Company completed additional financings and received total net proceeds of approximately $6.8 million after deducting placement agent fees and offering expenses. Research and Development Expenses Research and development expenses for the year ended December 31, 2024 decreased approximately $2.7 million, or 42%, as compared with the year ended December 31, 2023. The decrease in research and development expenses was primarily driven by the Company's cost rationalization measures in transitioning from a research company to a product development company. These actions resulted in a decrease of approximately $1.0 million of expense due to the wind-down of preclinical studies, a reduction of approximately $0.8 million in salary-related costs including stock-based compensation expense, and approximately $0.2 million in lab supplies associated with the reduction in headcount. Additionally, the Company experienced a reduction in clinical consulting fees and clinical trial-related fees of approximately $0.4 million incurred in connection with its IND filing for PH-762 and its former PH-762 trials in ACT and European clinical trial, as well as a decrease of approximately $0.2 million in manufacturing fees for PH-762 compared with 2023. General and Administrative Expenses General and administrative expenses were approximately $3.7 million for the year ended December 31, 2024 as compared with approximately $4.4 million for the year ended December 31, 2023, a decrease of 14%. The decrease was primarily due to decreases in professional fees for a total of approximately $0.4 million primarily related to legal and patent expenses and in the Company's D&O insurance premium of approximately $0.9 million as compared to the prior year. Net Loss Net loss was approximately $7.2 million, or ($9.08) per share, for the year ended December 31, 2024 as compared with a net loss of approximately $10.8 million, or $46.76 per share, for the year ended December 31, 2023. The decrease in net loss was primarily due to the changes in research and development expenses, as described above. About Phio Pharmaceuticals Corp. Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage biotechnology company advancing its proprietary INTASYL siRNA gene silencing technology to eliminate cancer. INTASYL can target and silence virtually any gene with high degree of specificity across a wide range of cell types and tissues. INTASYL is designed to enhance the ability of immune cells to more effectively kill tumor cells. INTASYL has also demonstrated enhancement to adoptive cell therapy. Notably, INTASYL is a self-delivering RNAi technology focused on immuno-oncology therapeutics without the need for formulation enhancements or manipulations to reach its target. Phio's lead clinical program, PH-762, is an INTASYL compound that silences PD-1. PH-762 is a potential non-surgical treatment for skin cancers. The on-going Phase 1b trial (NCT# 06014086) received FDA clearance for an Investigational New Drug Application to evaluate PH-762 in the treatment of cutaneous SCC, melanoma and Merkel cell carcinoma in second quarter of 2023. For additional information, visit the Company's website, www.phiopharma.com. Forward-Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words such as "intends," "believes," "anticipates," "indicates," "plans," "expects," "suggests," "may," "would," "should," "potential," "designed to," "will," "ongoing," "estimate," "forecast," "target," "predict," "could" and similar references, although not all forward-looking statements contain these words. These statements, which include statements regarding the anticipated benefits of our INTASYL™ RNAi platform, the results from our ongoing clinical trials and our ability to successfully complete our ongoing trials with the capital we currently have on hand, are based only on our current beliefs, expectations and assumptions and are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict and many of which are outside of our control. Our actual results may differ materially from those indicated in the forward-looking statements as a result of a number of important factors, including, but not limited to, the impact to our business and operations by inflationary pressures, rising interest rates, recession fears, the development of our product candidates, results from our preclinical and clinical activities, our ability to execute on business strategies, our ability to develop our product candidates with collaboration partners, and the success of any such collaborations, the timeline and duration for advancing our product candidates into clinical development, the timing or likelihood of regulatory filings and approvals, the success of our efforts to commercialize our product candidates if approved, our ability to manufacture and supply our product candidates for clinical activities, and for commercial use if approved, the scope of protection we are able to establish and maintain for intellectual property rights covering our technology platform, our ability to obtain future financing, market and other conditions and those risks identified in our Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q under the caption "Risk Factors" and in other filings the Company periodically makes with the SEC. Readers are urged to review these risk factors and to not act in reliance on any forward-looking statements, as actual results may differ from those contemplated by our forward-looking statements. Phio does not undertake to update forward-looking statements to reflect a change in its views, events or circumstances that occur after the date of this release, except as required by law. Contact: Phio Pharmaceuticals Corp. Jennifer Phillips: [email protected] Corporate Affairs PHIO PHARMACEUTICALS CORP. CONSOLIDATED STATEMENTS OF OPERATIONS (Amounts in thousands, except share and per share data) (Unaudited) PHIO PHARMACEUTICALS CORP. CONSOLIDATED BALANCE SHEETS (Amounts in thousands, except share data) (Unaudited) To view the source version of this press release, please visit https://www.newsfilecorp.com/release/246655