TPST

Executed a development collaboration with Senlang Biotechnology to advance certain in vivo CAR-T product candidates, including TPST-4003, a CD7-targeted next-generation in vivo CAR-T, with first patient dosing anticipated in the fourth quarter of 2026 and initial clinical data expected in the first half of 2027 Unveiled pipeline of next-generation in vivo CAR-T product candidates for oncology and immunology applications differentiated by CD-7 targeted mRNA/LNP delivery approach Appointed Drake Richey and John Yee, MD, MPH, to Board of Directors BRISBANE, Calif., Aug. 13, 2026 (GLOBE NEWSWIRE) -- Tempest Therapeutics, Inc. (Nasdaq: TPST) (“Tempest”), a clinical-stage biotechnology company developing a pipeline of advanced chimeric antigen receptor T-cell (“CAR-T”) product candidates, today reported financial results for the quarter ended June 30, 2026, and provided a business update. “We continue to execute against our strategy by advancing our next-generation in vivo CAR-T platform, expanding our expertise with the appointment of two new board members and strengthening our development capabilities through a new collaboration focused on our next-generation in vivo CAR-T candidate, TPST-4003,” said Matt Angel, Ph.D., President and Chief Executive Officer of Tempest. “These milestones reflect the momentum we are building across the business and reinforce our commitment to developing innovative therapies aiming to transform patient care. We are particularly excited to advance TPST-4003 toward an investigator-initiated clinical trial planned for the fourth quarter of 2026, an important step as we work to bring transformative options to patients.” Recent Highlights TPST-4003 TPST-2003 Corporate: Financial Results Second Quarter 2026 Tempest ended the quarter with $0.8 million in cash and cash equivalents, compared to $7.7 million on December 31, 2025. The decrease was primarily due to one-time transaction-associated costs incurred prior to or upon closing of the Asset Acquisition in February 2026, offset by the net proceeds of the Company’s private placement of common stock and warrants in March 2026 of $1.7 million and the Warrant Inducement of $1.7 million in the second quarter. Net loss and net loss per share for the quarter were $5.2 million and $0.34, respectively, compared to $7.9 million and $2.07, respectively, for the three months ended June 30, 2025. Research and development expenses for the quarter were $1.8 million compared to $3.9 million for the three months ended June 30, 2025. The $2.1 million decrease was primarily due to a decrease in costs incurred as a result of the re-prioritization of efforts after the Asset Acquisition in February 2026, offset by research and manufacturing costs related to the Company’s CAR-T product candidates. General and administrative expenses for the quarter were $3.4 million compared to $4.1 million for the same period in 2025. The $0.7 million decrease was primarily due to a decrease in one-time separation costs previously incurred in the second quarter of 2025, offset by other administrative expenses. Year-to-Date Cash used in operating activities for the six months ended June 30, 2026 was $10.4 million. Net loss and net loss per share for the six months ended June 30, 2026 were $32.9 million and $2.52, respectively, compared to $18.7 million and $5.17, respectively, for the same period in 2025. Research and development expenses for the six months ended June 30, 2026 were $1.9 million, compared to $11.5 million for the same period in 2025. The $9.6 million decrease was primarily due to a decrease in costs incurred as a result of re-prioritizing efforts towards exploring strategic alternatives initiated in April 2025 and resulting in the Asset Acquisition completed in February 2026. General and administrative expenses for the six months ended June 30, 2026 were $8.9 million, compared to $7.4 million for the same period in 2025. The $1.5 million increase was primarily due to one-time costs resulting from the Asset Acquisition completed in February 2026. Acquired in-process research and development expenses for the six months ended June 30, 2026 were $22.1 million compared to nil for the six months ended June 30, 2025. Costs incurred prior to or upon closing the Asset Acquisition in the prior three months ended March 31, 2026 were expensed as acquired in-process research and development. About Tempest Therapeutics Tempest is a clinical-stage biotechnology company pioneering a pipeline of next generation in vivo CAR-T therapies for autoimmune and oncology indications. Tempest’s immune reset technology is embodied in TPST-4003, the company’s lead in vivo CAR-T product candidate, which combines a dual-target CD19/BCMA CAR structure with the company’s proprietary CAR-T delivery platform to support broad B-cell lineage reset across multiple indications. The company’s additional preclinical programs leverage advanced payloads to create a modular in vivo CAR-T portfolio. Tempest envisions a world in which immune reset therapies bring safe, effective, and broadly accessible therapeutic options to patients in need. For additional information, visit Tempest’s website at https://www.tempesttx.com. Forward-Looking Statements This press release contains forward-looking statements, including within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended, and Section 27A of the Securities Act of 1933, as amended, concerning Tempest Therapeutics, Inc. These statements may discuss goals, intentions, and expectations as to future plans, trends, events, results of operations or financial condition, or otherwise, based on current beliefs of the management of Tempest Therapeutics, as well as assumptions made by, and information currently available to, management of Tempest Therapeutics. Forward-looking statements generally include statements that are predictive in nature and depend upon or refer to future events or conditions, and include words such as “may,” “will,” “should,” “would,” “could”, “expect,” “anticipate,” “plan,” “likely,” “believe,” “estimate,” “project,” “intend,” “goal”, “suggest”, “target” and other similar expressions. All statements that are not historical facts are forward-looking statements, including but not limited to, statements regarding: Tempest’s collaboration with Senlang and the advancement, development, design and potential benefits of TPST-4003; the planned investigator-initiated trial of TPST-4003, including the expected patient population, indications, number of patients, timing of first patient enrollment and dosing, expected assessments and anticipated timing and nature of initial and interim clinical data;  the potential applicability of Tempest’s platform and product candidates across autoimmune and oncology indications; Tempest’s business development and partnering plans, including in China; and Tempest’s need for, and ability to obtain, additional capital to fund its planned programs and operations and continue as a going concern. All forward-looking statements in this press release are based on Tempest Therapeutics’ current expectations, estimates and projections about its industry as well as management’s current beliefs and expectations of future events only as of today and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to Tempest Therapeutics’ need for additional capital to fund its planned programs and operations and to continue to operate as a going concern; unexpected safety or efficacy data observed during preclinical or clinical trials; the possibility that results from prior clinical trials and preclinical studies may not necessarily be predictive of future results; past results may not be indicative of future results; clinical trial site activation or enrollment rates that are lower than expected; loss of key personnel; changes in expected or existing competition; changes in the regulatory environment; risks relating to volatility and uncertainty in the capital markets for biotechnology companies; and unexpected litigation or other disputes. These and other factors that may cause actual results to differ from those expressed or implied are discussed in greater detail in the “Risk Factors” section of Tempest Therapeutics' Annual Report on Form 10-K for the year ended December 31, 2025, filed with the Securities and Exchange Commission (“SEC”) on March 30, 2026, and in other documents filed by Tempest Therapeutics from time to time with the SEC. Except as required by applicable law, Tempest Therapeutics undertakes no obligation to revise or update any forward-looking statement, or to make any other forward-looking statements, whether as a result of new information, future events or otherwise. These forward-looking statements should not be relied upon as representing Tempest Therapeutics’ views as of any date subsequent to the date of this press release and should not be relied upon as prediction of future events. In light of the foregoing, investors are urged not to rely on any forward-looking statement in reaching any conclusion or making any investment decision about any securities of Tempest Therapeutics. Investor Contacts: Sylvia WheelerWheelhouse Life Science [email protected] Aljanae Reynolds Wheelhouse Life Science [email protected]

Advancing a pipeline of in vivo CAR-T product candidates for oncology and immunology applications differentiated by CD7-targeted mRNA/LNP delivery approach Lead candidate TPST-4003 combines proprietary CD7-targeted mRNA/LNP delivery with a clinically validated dual-targeting CD19/BCMA CAR construct to support broad B-cell lineage reset across multiple indications First investigator-initiated trial expected to enroll approximately 10 patients with nervous system autoimmune diseases, including MG and MS, with first patient dosing anticipated in the fourth quarter of 2026 and initial clinical data expected in the first half of 2027 BRISBANE, Calif., July 15, 2026 (GLOBE NEWSWIRE) -- Tempest Therapeutics, Inc. (Nasdaq: TPST) (“Tempest”), a clinical-stage biotechnology company developing a pipeline of advanced chimeric antigen receptor T-cell (“CAR-T”) product candidates, today announced details of its next-generation in vivo CAR-T platform. The company plans to advance TPST-4003, its lead in vivo CAR-T product candidate, into a first investigator-initiated clinical trial in patients with nervous system autoimmune diseases, initially focusing on myasthenia gravis (“MG”) and multiple sclerosis (“MS”). The study is expected to enroll approximately 10 patients, with first patient dosing anticipated in the fourth quarter of 2026. TPST-4003 combines Tempest’s next-generation CD7-targeted mRNA lipid nanoparticle (“CD7-tLNP”) delivery platform with the same dual-targeting CD19 B-cell maturation antigen (“CD19/BCMA”) chimeric antigen receptor (“CAR”) architecture used in TPST-2003, the company's clinical-stage CAR-T program. Interim Phase 1/2a clinical data generated with TPST-2003 demonstrating the achievement of a 100% complete response rate, together with its successful U.S. manufacturing, provide important support of the underlying CAR construct, establishing a foundation for TPST-4003. “We are excited to announce the strategic prioritization of our next-generation in vivo CAR-T pipeline and our plan to advance TPST-4003 toward an anticipated first patient dosing later this year,” said Matt Angel, Ph.D., President and Chief Executive Officer of Tempest. “We believe our differentiated in vivo CAR-T platform may enable broader addressable T-cell coverage and support scalable repeat dosing once developed and commercialized, supporting future commercial attractiveness of in vivo CAR-T therapy. The lead product candidate in our pipeline, TPST-4003, is being designed to enable broad B-cell lineage depletion and reset with its dual CD19/BCMA targeting architecture, with the goal of potentially delivering improved efficacy and durability compared with single-target CAR approaches. We look forward to advancing TPST-4003 into clinical development later this year.” Planned Investigator-Initiated Trial of TPST-4003 The first planned investigator-initiated trial is expected to evaluate TPST-4003 in approximately 10 patients with nervous system autoimmune diseases, initially focusing on MG and MS. Initial study planning has involved discussions with six prospective clinical centers and principal investigators experienced in neurological autoimmune diseases. The company expects first patient enrollment and dosing to occur in the fourth quarter of 2026. The study is expected to assess safety, cellular kinetics and pharmacodynamic activity following initial dosing. Key assessments are expected to include treatment-emergent adverse events and serious adverse events; the generation and expansion of peripheral blood CD4+ and CD8+ CAR-T cells and CD56+ CAR-NK cells; CAR transgene copy number; and the depth and kinetics of CD19+ B-cell depletion and B-cell subset reconstitution. Where clinically appropriate, exploratory assessments may also include the detection of CAR-positive immune cells in cerebrospinal fluid and the evaluation of B-cell depletion in lymphoid tissue. Disease-specific clinical activity will be evaluated using established measures. Initial safety and pharmacodynamic data from the first patients are expected in the first half of 2027, followed by an interim clinical update including preliminary safety, pharmacodynamic and efficacy data in the second half of 2027. Additional preclinical programs leverage advanced payloads and create a modular in vivo CAR-T portfolio. These include TPST-001 for non-B-cell hematologic malignancies and TPST-002 for solid tumors. Tempest’s in vivo CAR-T platform, CD7-tLNP, is being designed to expand the potential of next-generation in vivo CAR-T therapy through three core differentiators: Broader T-Cell Reach: The platform is being engineered to efficiently target both CD4+ and CD8+ T-cell populations, targeting broad CAR expression across the key cellular drivers of durable immunity. This comprehensive T-cell engagement is intended to support a more balanced and effective therapeutic response. Better Delivery Logic: A differentiated targeting ligand, combined with rapid cellular internalization and a chemically optimized mRNA payload, is being designed to maximize intracellular delivery and CAR protein expression. Nucleoside-modified mRNA and optimized construct architecture together target a reduced innate immune sensing, extended functional mRNA activity, and robust yet transient CAR expression – enhancing delivery efficiency while preserving the advantages of an in vivo approach. Scalable In Vivo CAR-T: By increasing CAR expression on a per-particle basis, the platform is being designed to achieve meaningful biological activity at lower doses, supporting improved manufacturing efficiency, reduced cost of goods, and the potential for scalable, repeatable treatment. Together, we believe these capabilities may position the CD7-tLNP platform as a differentiated solution for the next generation of in vivo CAR-T therapies. About TPST-4003 TPST-4003 is a preclinical, in vivo dual-targeting CD19/BCMA CAR-T product candidate that combines proprietary CD7-targeted mRNA/LNP delivery with a clinically validated dual-target CAR architecture utilized in the company's TPST-2003 CAR-T program. Targeting broad B-cell lineage depletion and reset, TPST-4003 is being designed to address a range of autoimmune and oncology indications, initially including MG and MS. Forward-Looking Statements This press release contains forward-looking statements (including within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended, and Section 27A of the Securities Act of 1933, as amended, concerning Tempest. These statements may discuss goals, intentions, and expectations as to future plans, trends, events, results of operations or financial condition, or otherwise, based on current beliefs of the management of Tempest, as well as assumptions made by, and information currently available to, management of Tempest. Forward-looking statements generally include statements that are predictive in nature and depend upon or refer to future events or conditions, and include words such as “may,” “will,” “should,” “would,” “could”, “expect,” “anticipate,” “plan,” “likely,” “believe,” “estimate,” “project,” “intend,” “goal”, “suggest”, “target” and other similar expressions. All statements that are not historical facts are forward-looking statements, including but not limited to, statements regarding: Tempest’s strategic prioritization of its next-generation in vivo CAR-T platform program; the advancement, development, design, potential benefits and differentiation of TPST-4003, TPST-001, TPST-002 and Tempest’s CD7-tLNP platform; the planned investigator-initiated trial of TPST-4003, including the expected patient population, indications, number of patients, timing of first patient enrollment and dosing, expected assessments and anticipated timing and nature of initial and interim clinical data; the potential ability of TPST-4003 to enable broad B-cell lineage depletion and reset and to deliver improved efficacy or durability compared with single-target CAR approaches; the potential scalability, repeat dosing, manufacturing efficiency, cost-of-goods benefits and commercial attractiveness of Tempest’s in vivo CAR-T approach; the potential applicability of Tempest’s platform and product candidates across autoimmune and oncology indications; and Tempest’s ability to achieve its operational plans. All forward-looking statements in this press release are based on Tempest’s current expectations, estimates and projections about its industry as well as management’s current beliefs and expectations of future events only as of today and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to Tempest’s need for additional capital to fund its planned programs and operations and to continue to operate as a going concern; unexpected safety or efficacy data observed during preclinical or clinical trials; the possibility that results from prior clinical trials and preclinical studies may not necessarily be predictive of future results; past results may not be indicative of future results; clinical trial site activation or enrollment rates that are lower than expected; loss of key personnel; changes in expected or existing competition; changes in the regulatory environment; risks relating to volatility and uncertainty in the capital markets for biotechnology companies; and unexpected litigation or other disputes. These and other factors that may cause actual results to differ from those expressed or implied are discussed in greater detail in the “Risk Factors” section of Tempest's Annual Report on Form 10-K for the year ended December 31, 2025, filed with the Securities and Exchange Commission (“SEC”) on March 30, 2026, and in other documents filed by Tempest from time to time with the SEC. Except as required by applicable law, Tempest undertakes no obligation to revise or update any forward-looking statement, or to make any other forward-looking statements, whether as a result of new information, future events or otherwise. These forward-looking statements should not be relied upon as representing Tempest’s views as of any date subsequent to the date of this press release and should not be relied upon as prediction of future events. In light of the foregoing, investors are urged not to rely on any forward-looking statement in reaching any conclusion or making any investment decision about any securities of Tempest. Investor Contacts: Sylvia WheelerWheelhouse Life Science [email protected] Aljanae Reynolds Wheelhouse Life Science [email protected]

Announced positive interim data from the ongoing REDEEM-1 Phase 1/2a trial of TPST-2003 in patients with relapsed/refractory multiple myeloma (rrMM) Announced Cincinnati Children’s Applied Gene and Cell Therapy Center (“AGCTC”) as Lead Manufacturing Partner Appointed Andrew Fang, Ph.D., as Head of Business Development BRISBANE, Calif., May 14, 2026 (GLOBE NEWSWIRE) -- Tempest Therapeutics, Inc. (Nasdaq: TPST) (“Tempest”), a clinical-stage biotechnology company developing a pipeline of advanced CAR-T cell therapy product candidates to treat cancer, today reported financial results for the quarter ended March 31, 2026, and provided a corporate update. “We made strong progress in the first quarter as we continued to execute across our lead program TPST-2003,” said Matt Angel, Ph.D., President and Chief Executive Officer of Tempest. “We advanced key activities supporting the planned initiation of our U.S. registrational study of TPST-2003 in patients with rrMM, including announcing our lead manufacturing partner AGCTC and taking delivery of the TPST-2003 lentiviral vector, a critical component in the manufacturing of TPST-2003. At the same time, we strengthened our ability to unlock value across our remaining portfolio with the appointment of Andrew Fang, Ph.D., as our Head of Business Development, whose focus on strategic partnerships, licensing and corporate transactions will help position us for long-term growth. We believe these milestones further reinforce our momentum and our path toward delivering meaningful impact for patients and shareholders alike.” Recent Highlights TPST-2003 Positive interim results across two ongoing clinical trials (REDEEM-1 Phase 1/2a trial of TPST-2003 in patients with rrMM, and POEMS-1 Phase 1 trial evaluating TPST-2003 in the rare disease, POEMS syndrome), both of which are being sponsored and conducted by Tempest’s partner, Novatim Immune Therapeutics: 100% complete response (CR) rate among all 15 CAR-T-naïve efficacy evaluable patients treated with TPST-2003 across REDEEM-1 and POEMS-1 trials. Favorable safety profile with no Grade ≥3 cytokine release syndrome (CRS) or immune effector cell-associated neurotoxicity syndrome (ICANS) in REDEEM-1 trial appears to be emerging as a potentially differentiating attribute in its class. Prior investigator-initiated trial (IIT) reached median progression free survival (PFS) of 23.1 months, including in patients with extramedullary disease. 44 patients with rrMM treated to date across three studies. The selection of Cincinnati Children’s AGCTC as the lead contract development and manufacturing partner to conduct the formal technology transfer of TPST-2003, Tempest’s dual-targeting CD19/BCMA CAR-T therapy under development for the treatment of relapsed/refractory multiple myeloma (rrMM). Further to the selection of AGCTC as lead partner, AGCTC took delivery of the TPST-2003 lentiviral vector, a critical component used in the manufacturing of TPST-2003, supporting plans to initiate the first potentially registrational study to evaluate a dual-targeting CAR-T therapy in patients with rrMM, including patients who are experiencing extramedullary disease (EMD), later this year. Corporate: Announced the appointment of Andrew Fang, Ph.D., as Head of Business Development. In his role, Dr. Fang will lead Tempest’s global business development efforts, including strategic partnerships, cross-border licensing and corporate transactions, with a particular focus on expanding Tempest’s outreach and partnering efforts in China. Announced closing of strategic asset acquisition of new dual-targeting CAR-T assets from Factor Bioscience Inc. and Erigen LLC (“Asset Acquisition”). The transaction brought Tempest a portfolio of next-generation CAR-T assets, including TPST-2003, a clinical-stage dual-targeting CD-19/BCMA CAR-T with strategic partner-funded biologics license application (“BLA”) filing in China planned for 2027. In March 2026, Tempest announced up to $6 million private placement (the “2026 Offering”) of common stock and warrants, with $2 million upfront and up to $4 million of potential aggregate gross proceeds upon the exercise in full of warrants, subject to shareholder approval. Financial Results First Quarter 2026 Tempest ended the quarter with $1.8 million in cash and cash equivalents, compared to $7.7 million on December 31, 2025. The decrease was primarily due to one-time transaction-associated costs incurred prior to or upon closing the Asset Acquisition, offset by net proceeds from the 2026 Offering of $1.7 million. Net loss and net loss per share for the quarter were $27.7 million and $2.53, respectively, compared to $10.9 million and $3.16, respectively, for the three months ended March 31, 2025. Research and development expenses for the quarter were $0.1 million compared to $7.6 million for the three months ended March 31, 2025. The $7.5 million decrease was primarily due to a decrease in costs incurred as a result of re-prioritizing efforts towards exploring strategic alternatives initiated in April 2025 and resulting in the Asset Acquisition completed in February 2026. General and administrative expenses for the quarter were $5.4 million compared to $3.3 million for the same period in 2025. The $2.1 million increase was primarily due to one-time costs resulting from the Asset Acquisition completed in February 2026. Acquired in-process research and development expenses for the quarter were $22.1 million compared to nil for the three months ended March 31, 2025. Costs incurred prior to or upon closing the Asset Acquisition in the three months ended March 31, 2026 were expensed as acquired in-process research and development. About Tempest Therapeutics Tempest Therapeutics is a clinical-stage biotechnology company developing a pipeline of advanced CAR-T cell therapy product candidates to treat cancer. Tempest is headquartered in Brisbane, California. More information about Tempest can be found on the company’s website at https://www.tempesttx.com. Forward-Looking Statements This press release contains forward-looking statements (including within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended, and Section 27A of the Securities Act of 1933, as amended, concerning Tempest Therapeutics, Inc. These statements may discuss goals, intentions, and expectations as to future plans, trends, events, results of operations or financial condition, or otherwise, based on current beliefs of the management of Tempest Therapeutics, as well as assumptions made by, and information currently available to, management of Tempest Therapeutics. Forward-looking statements generally include statements that are predictive in nature and depend upon or refer to future events or conditions, and include words such as “may,” “will,” “should,” “would,” “could”, “expect,” “anticipate,” “plan,” “likely,” “believe,” “estimate,” “project,” “intend,” “goal”, “suggest”, “target” and other similar expressions. All statements that are not historical facts are forward-looking statements, including but not limited to, statements regarding: Tempest Therapeutics’ plan to initiate the first potentially registrational study to evaluate a dual-targeting CAR-T therapy in patients with rrMM, focus on expanding Tempest’s outreach and partnering efforts in China, plans for BLA filing in China, and expectations regarding shareholder approval in connection with the 2026 Offering and the potential aggregate proceeds therefrom; anticipated therapeutic benefit and regulatory development of Tempest Therapeutics’ product candidates; and Tempest’s ability to promptly raise additional funds to further expand the Company’s cash runway. All forward-looking statements in this press release are based on Tempest Therapeutics’ current expectations, estimates and projections about its industry as well as management’s current beliefs and expectations of future events only as of today and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to Tempest Therapeutics’ need for additional capital to fund its planned programs and operations and to continue to operate as a going concern; unexpected safety or efficacy data observed during preclinical or clinical trials; the possibility that results from prior clinical trials and preclinical studies may not necessarily be predictive of future results; past results may not be indicative of future results; clinical trial site activation or enrollment rates that are lower than expected; loss of key personnel; changes in expected or existing competition; changes in the regulatory environment; risks relating to volatility and uncertainty in the capital markets for biotechnology companies; and unexpected litigation or other disputes. These and other factors that may cause actual results to differ from those expressed or implied are discussed in greater detail in the “Risk Factors” section of Tempest Therapeutics' Annual Report on Form 10-K for the year ended December 31, 2025, filed with the Securities and Exchange Commission (“SEC”) on March 30, 2026, and in other documents filed by Tempest Therapeutics from time to time with the SEC. Except as required by applicable law, Tempest Therapeutics undertakes no obligation to revise or update any forward-looking statement, or to make any other forward-looking statements, whether as a result of new information, future events or otherwise. These forward-looking statements should not be relied upon as representing Tempest Therapeutics’ views as of any date subsequent to the date of this press release and should not be relied upon as prediction of future events. In light of the foregoing, investors are urged not to rely on any forward-looking statement in reaching any conclusion or making any investment decision about any securities of Tempest Therapeutics. (1) Results have been adjusted to reflect the one-for-thirteen reverse stock split effected in April 2025. Investor Contacts: Sylvia WheelerWheelhouse Life Science [email protected] Aljanae Reynolds Wheelhouse Life Science [email protected]

Completed strategic acquisition of dual-targeting CAR-T assets from Factor Bioscience Inc. Named Matt Angel, Ph.D., Chief Executive Officer & President Announced positive interim data from the ongoing REDEEM-1 Phase 1/2a trial of TPST-2003 in patients with relapsed/refractory multiple myeloma (rrMM) BRISBANE, Calif., March 30, 2026 (GLOBE NEWSWIRE) -- Tempest Therapeutics, Inc. (Nasdaq: TPST) (“Tempest”), a clinical-stage biotechnology company developing a pipeline of advanced CAR-T cell therapy product candidates to treat cancer, today reported financial results for the year ended December 31, 2025, and provided a corporate update. “2025 was a transformative year for Tempest as we strengthened our pipeline with the strategic acquisition of a portfolio of next-generation CAR-T assets,” said Matt Angel, Ph.D., President and Chief Executive Officer of Tempest. “The portfolio is already proving potentially fruitful as we reported encouraging early clinical data from our lead CAR-T program, TPST-2003, which is being tested in a Phase 1/2a trial in patients with relapsed or refractory multiple myeloma. The data, which suggests a favorable safety and efficacy profile for TPST-2003, reinforced our belief that this therapy has the potential to differentiate itself from currently approved CAR-T treatments and provide a meaningful option for patients who continue to face limited durable treatment options. We look forward to the potential initiation of a U.S. registrational study of TPST-2003 in patients with rrMM later this year, while we continue our strategy of leveraging partner-funded and externally supported development where possible to advance our pipeline.” 2025 & Recent Accomplishments TPST-2003 Announced positive interim results from the ongoing REDEEM-1 Phase 1/2a trial of TPST-2003 in patients with rrMM, which is being sponsored and conducted by Tempest’s partner, Novatim Immune Therapeutics: 100% complete response (CR) rate among all six efficacy evaluable patients as of the January 31, 2026 data cutoff Favorable safety profile with no Grade >3 cytokine release syndrome (“CRS”) or immune effector cell-associated neurotoxicity syndrome (“ICANS”) appears to be emerging as a potentially differentiating attribute in its class Prior investigator-initiated trial (“IIT”) reached median progression free survival (PFS) of 23.1 months, including in patients with extramedullary disease 36 patients with rrMM treated to date across two studies Corporate: Announced closing of strategic acquisition of new dual-targeting CAR-T assets from Factor Bioscience Inc. and its affiliates All-stock transaction brought Tempest a portfolio of next-generation CAR-T assets, including TPST-2003, a clinical-stage dual-targeting CD-19/BCMA CAR-T with strategic partner-funded biologics license application (BLA) filing in China planned for 2027 In November 2025, announced up to $8.35 million registered direct offering (an “RDO” and, such offering, the “November Offering”) of common stock and concurrent private placement of warrants priced at-the-market under Nasdaq In March 2026, announced up to $6 million private placement (the “2026 Offering”) of common stock and warrants, with $2 million upfront and up to $4 million of potential aggregate gross proceeds upon the exercise in full of warrants Amezalpat (TPST-1120) (clinical PPARα antagonist): Received clearance to proceed with pivotal trial of amezalpat combination therapy for first-line hepatocellular carcinoma (“HCC”) in China Granted orphan drug designation from the European Medicines Agency for amezalpat for the treatment of patients with HCC Reported new data at the 2025 American Association for Cancer Research (AACR) Annual Meeting supporting the immune component of amezalpat’s dual mechanism of action and reinforcing its potential as a novel cancer treatment Granted both Orphan Drug and Fast Track designations by the U.S. Food and Drug Administration (“FDA”) for amezalpat for the treatment of patients with HCC TPST-1495 (clinical dual EP2/4 prostaglandin receptor antagonist) Granted Orphan Drug designation by the FDA to treat patients with Familial Adenomatous Polyposis (“FAP”) Received a “Study May Proceed” letter from the FDA to evaluate TPST-1495 in a Phase 2 Trial for the treatment of FAP Potential Future Milestones TPST-2003 Present results from the ongoing Phase 1/2a REDEEM-1 study, as well as updated data from the Phase 1/2 IIT, in 2026 Submit a U.S. IND application and, subject to clearance, initiate a Phase 2b U.S. registrational study of TPST-2003 in patients with rrMM in 2026 TPST-1495 Initiate a Phase 2 study of TPST-1495 in FAP, with first patient enrollment expected in 2026. The study is expected to be funded by the National Cancer Institute and conducted through the Cancer Prevention Clinical Trials Network, enabling advancement without internal capital deployment. Financial Results Year End 2025 Tempest ended the year with $7.7 million in cash and cash equivalents, compared to $30.3 million on December 31, 2024. The decrease was primarily due to cash used in operating activities, offset by net proceeds from the issuance of common stock of $4.1 million from the RDO in June, $3.8 million from the November Offering and $2.8 million from Tempest’s at-the-market offering program. Net loss and net loss per share for the year were $26.3 million and $6.33, respectively, compared to $41.8 million and $19.50, respectively, for the same period in 2024. Research and development expenses for the year were $12.6 million compared to $28.5 million for the same period in 2024. The $15.9 million decrease was primarily due to a decrease in costs incurred as a result of re-prioritizing efforts towards exploring strategic alternatives. General and administrative expenses for the year were $14.0 million compared to $13.6 million for the same period in 2024. The $0.4 million increase was primarily due to one-time separation costs for employees terminated during the period. About Tempest Therapeutics Tempest Therapeutics is a clinical-stage biotechnology company developing a pipeline of CAR-T cell therapy and small molecule product candidates to treat cancer. Tempest is headquartered in Brisbane, California. More information about Tempest can be found on the company’s website at https://www.tempesttx.com Forward-Looking Statements This press release contains forward-looking statements (including within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended, and Section 27A of the Securities Act of 1933, as amended (the “Securities Act”)) concerning Tempest Therapeutics, Inc. These statements may discuss goals, intentions, and expectations as to future plans, trends, events, results of operations or financial condition, or otherwise, based on current beliefs of the management of Tempest Therapeutics, as well as assumptions made by, and information currently available to, management of Tempest Therapeutics. Forward-looking statements generally include statements that are predictive in nature and depend upon or refer to future events or conditions, and include words such as “may,” “will,” “should,” “would,” “could”, “expect,” “anticipate,” “plan,” “likely,” “believe,” “estimate,” “project,” “intend,” and other similar expressions. All statements that are not historical facts are forward-looking statements, including but not limited to, statements regarding: Tempest Therapeutics’ plan to present data from clinical trials, including the REDEEM-1 trial; the design, initiation, progress, timing, scope and results of clinical trials, including the anticipated initiation of U.S. registrational trial for TPST-2003 in 2026 and patient enrollment for the Phase 2 study of TPST-1495 in 2026; the planned advancement of a diversified next-generation CAR-T pipeline; anticipated therapeutic benefit and regulatory development of Tempest Therapeutics’ product candidates, including TPST-2003, Amezalpat and TPST-1495; the use of proceeds from each of the November 2025 Offering and 2026 Offering, and the potential aggregate proceeds therefrom; and Tempest Therapeutics’ ability to achieve its operational plans. Any forward-looking statements in this press release are based on Tempest Therapeutics’ current expectations, estimates and projections about its industry as well as management’s current beliefs and expectations of future events only as of today and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to Tempest Therapeutics’ need for additional capital to fund its planned programs and operations and to continue to operate as a going concern; unexpected safety or efficacy data observed during preclinical or clinical trials; the possibility that results from prior clinical trials and preclinical studies may not necessarily be predictive of future results; past results may not be indicative of future results; clinical trial site activation or enrollment rates that are lower than expected; loss of key personnel; changes in expected or existing competition; changes in the regulatory environment; risks relating to volatility and uncertainty in the capital markets for biotechnology companies; and unexpected litigation or other disputes. These and other factors that may cause actual results to differ from those expressed or implied are discussed in greater detail in the “Risk Factors” section of Tempest Therapeutics’ Quarterly Report on Form 10-Q for the quarter ended September 30, 2025, filed with the Securities and Exchange Commission (“SEC”) on November 5, 2025, and the “Risk Factors” section under Proposal 5 contained in Tempest’s definitive proxy statement on Schedule 14A, filed with the SEC on December 31, 2025, and in other documents filed by Tempest Therapeutics from time to time with the SEC. Except as required by applicable law, Tempest Therapeutics undertakes no obligation to revise or update any forward-looking statement, or to make any other forward-looking statements, whether as a result of new information, future events or otherwise. These forward-looking statements should not be relied upon as representing Tempest Therapeutics’ views as of any date subsequent to the date of this press release and should not be relied upon as prediction of future events. In light of the foregoing, investors are urged not to rely on any forward-looking statement in reaching any conclusion or making any investment decision about any securities of Tempest Therapeutics. (1) Results have been adjusted to reflect the one-for-thirteen reverse stock split effected in April 2025. (1) Results have been adjusted to reflect the one-for-thirteen reverse stock split effected in April 2025. Investor Contacts: Sylvia Wheeler Wheelhouse Life Science Advisors [email protected] Aljanae Reynolds Wheelhouse Life Science Advisors [email protected]

100% complete response (CR) rate among all six efficacy evaluable patients Favorable safety profile with no Grade >3 CRS or ICANS Prior investigator-initiated trial (IIT) reached median progression free survival (PFS) of 23.1 months, including in patients with extramedullary disease 36 patients with relapsed/refractory multiple myeloma treated to date across two studies Tempest plans to submit a U.S. IND and, subject to clearance, initiate a U.S. registrational study in 2026 BRISBANE, Calif., Feb. 25, 2026 (GLOBE NEWSWIRE) -- Tempest Therapeutics, Inc. (Nasdaq: TPST) (“Tempest”), a clinical-stage biotechnology company developing a pipeline of advanced cell therapy and small molecule product candidates to treat cancer, today announced clinical data from the ongoing REDEEM-1 Phase 1/2a trial evaluating TPST-2003, a CD19/BCMA dual-targeting CAR-T therapy. TPST-2003 is an autologous CD19/BCMA dual-targeting CAR-T therapy designed to improve response depth and durability in patients with relapsed/refractory multiple myeloma (“rrMM”) through a parallel dual-targeting CAR structure designed to address tumor heterogeneity and antigen escape. TPST-2003 is being developed in China by Tempest’s partner, Novatim Immune Therapeutics (“Novatim”). Under its agreement with Novatim, Tempest has the exclusive right to develop TPST-2003 outside of China, India, Turkey, and Russia. As of the January 31, 2026 data cutoff, a total of 36 patients with rrMM had received one infusion of TPST-2003, including 24 patients in a prior Phase 1/2 IIT and 12 patients in the ongoing REDEEM-1 trial, representing one of the largest datasets evaluating a CD19/BCMA dual-targeting CAR-T therapy. As of the data cutoff, patients enrolled in the REDEEM-1 trial have received a median of four prior lines of therapy. All six patients currently evaluable for efficacy in the REDEEM-1 trial – three treated at dose level 1 (1 x 106 cells/kg) and three at dose level 2 (2 x 106 cells/kg) – achieved a CR according to the International Myeloma Working Group (IMWG) uniform response criteria. Among 25 evaluable patients with measurable disease at baseline across both studies, the overall response rate (“ORR”) was 100% (25/25). Clinical responses were observed consistently across dose levels and study settings, which Tempest believes supports the reproducibility of TPST-2003’s parallel dual-targeting CAR architecture. Tempest plans to present the results of the REDEEM-1 trial and updated results from the IIT at a scientific meeting later this year. “These results have the potential to raise the bar for clinical effect in relapsed/refractory multiple myeloma (rrMM),” said Dr. Matt Angel, President and Chief Executive Officer of Tempest. “The data from the ongoing REDEEM-1 trial suggest a favorable safety and efficacy profile that could set TPST-2003 apart from currently approved CAR-T therapies and offer a safe, effective option for patients with rrMM. We believe that replicating these results in the remainder of the REDEEM-1 trial and also in a registrational trial would position TPST-2003 as a class-leading therapy for rrMM, and we have therefore made the decision to accelerate our development of TPST-2003. Given the favorable safety profile and demonstrated clinical effect, Tempest is also exploring potential development of TPST-2003 to include patients with large B-cell lymphoma (LBCL) and other related indications.” Favorable Safety Profile Observed Across All Dose Levels in REDEEM-1 As of the January 15, 2026 data cutoff, TPST-2003 demonstrated a favorable safety profile across all dose levels evaluated in REDEEM-1. As of the data cutoff, patients in the REDEEM-1 trial experienced: No Grade three or higher cytokine release syndrome (CRS) One patient treated at the highest dose level (3 x 106 cells/kg) experienced low-grade immune effector cell-associated neurotoxicity syndrome (“ICANS”) No Grade three or higher ICANS The observed safety profile together with the consistency of responses observed in the REDEEM-1 trial support Tempest’s plan to accelerate its development timeline and meet with the FDA to discuss initiating a U.S. registrational study later this year. Deep Responses and Durable Disease Control Tempest believes the results of the ongoing REDEEM-1 study are consistent with prior clinical results, including a 24-patient Phase 1/2 IIT. In the IIT, among 19 evaluable patients with measurable disease at baseline: ORR was 100% (19/19) CR rate was 89.5% (17/19) At the highest dose level, CR was observed in 100% of patients (5/5) The IIT also demonstrated durable disease control, with: Median progression-free survival (PFS) of 23.1 months across all patients Median PFS of 23.1 months in patients with extramedullary disease (EMD) All evaluable patients remained MRD-negative at month 12 (5/5) Patients with EMD are often associated with worse outcomes and shorter disease control in rrMM. Tempest believes these findings support continued evaluation of TPST-2003 for its potential to deliver both deep and durable responses in advanced disease. Parallel Dual-Targeting CAR Structure Designed to Address Resistance Mechanisms TPST-2003 incorporates a proprietary parallel dual-targeting CAR architecture designed by Tempest’s partner, Novatim Immune Therapeutics. “The differentiated parallel structure of TPST-2003’s dual-targeting CAR is designed to address the challenges of relapse and suboptimal efficacy of other approaches,” said Guoxiang Wu, M.D., Chairman and General Manager of Novatim. “TPST-2003 has shown compelling efficacy results in rrMM and POEMS syndrome. In particular, we believe the favorable safety profile of TPST-2003 supports its potential in additional indications including autoimmune diseases and may provide broader clinical benefits for patients worldwide.” Positioning within the Treatment Landscape Approved CAR-T therapies have demonstrated meaningful clinical benefit in patients with rrMM and represent an important treatment option in later lines of therapy. However, relapse remains common, and treatment can be associated with toxicity management challenges and manufacturing constraints. TPST-2003 was designed with a parallel dual-targeting CAR structure intended to address tumor heterogeneity and antigen escape, mechanisms believed to contribute to disease progression following currently available therapies. In addition, Tempest’s parallel CAR architecture is being applied across multiple programs, including: TPST-3003, an allogeneic CD19/BCMA dual-targeting CAR-T therapy under development for rrMM TPST-4003, an in vivo CD19/BCMA dual-targeting CAR-T therapy under development for systemic lupus erythematosus (SLE) and other immunology disorders Tempest expects initial clinical data from both programs later this year and believes this platform approach may allow these therapies to ultimately benefit a larger number of patients. Next Steps Tempest plans to present the complete results from the ongoing Phase 1/2a REDEEM-1 study, as well as updated data from the Phase 1/2 IIT, in 2026. Based on data generated to date, Tempest intends to submit a U.S. IND application and, subject to clearance, initiate a U.S. registrational study of TPST-2003 in 2026. About REDEEM-1 REDEEM-1 (Study nos. CTR20233309/NCT06223646) is a Phase 1/2a clinical trial evaluating TPST-2003 in patients with relapsed/refractory multiple myeloma, including patients with high-risk cytogenetics and patients with extramedullary disease. The REDEEM-1 trial has a targeted full enrollment of 29 patients. The REDEEM-1 trial is sponsored and being conducted by Tempest’s partner, Novatim Immune Therapeutics, with a total of eight clinical sites registered in China: Peking Union Medical College Hospital (Dr. Jian Li; lead site), The First Affiliated Hospital of Nanchang University (Dr. Fei Li), Peking University First Hospital (Dr. Yujin Dong), Henan Cancer Hospital (Dr. Baijun Fang), Shanxi Provincial Cancer Hospital (Dr. Liping Su), The Second Xiangya Hospital of Central South University (Dr. Hongling Peng), The First Affiliated Hospital of China Medical University (Dr. Xiaojing Yan), and The Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College (Dr. Dehui Zou). Additional clinical trials evaluating TPST-2003 A Phase 1/2 IIT (Study no. NCT04714827) is evaluating TPST-2003 in patients with relapsed/refractory multiple myeloma, including patients with high-risk cytogenetics and patients with extramedullary disease. The IIT is sponsored and being conducted by Tempest’s partner, Novatim Immune Therapeutics, with a total of two clinical sites registered in China: Shanghai Fourth People’s Hospital (Dr. Weijun Fu; lead site) and Shanxi Provincial Cancer Hospital (Dr. Liping Su). A Phase 1 trial (Study nos. CTR20242409/NCT06518876) is evaluating TPST-2003 in patients with POEMS, a rare blood disorder caused by abnormal plasma cells. The Phase 1 trial is sponsored and being conducted by Tempest’s partner, Novatim Immune Therapeutics, with a total of three clinical sites registered in China: Peking Union Medical College Hospital (Dr. Jian Li; lead site), Xuanwu Hospital Capital Medical University (Dr. Wanling Sun), and West China Hospital, Sichuan University (Dr. Yu Wu). About Tempest Therapeutics Tempest Therapeutics is a clinical-stage biotechnology company developing a pipeline of advanced cell therapy and small molecule product candidates to treat cancer. Tempest is headquartered in Brisbane, California. More information about Tempest can be found on the company’s website at https://www.tempesttx.com. Forward-Looking Statements This press release contains forward-looking statements (including within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended, and Section 27A of the Securities Act of 1933, as amended (the “Securities Act”)) concerning Tempest Therapeutics, Inc. These statements may discuss goals, intentions, and expectations as to future plans, trends, events, results of operations or financial condition, or otherwise, based on current beliefs of the management of Tempest Therapeutics, as well as assumptions made by, and information currently available to, management of Tempest Therapeutics. Forward-looking statements contained in this press release include but are not limited to statements relating to: Tempest Therapeutics’ plan to present data from clinical trials, including the REDEEM-1 trial; the design, initiation, progress, timing, scope and results of clinical trials, including the anticipated initiation of U.S. registrational trial for TPST-2003 in 2026; Tempest Therapeutics’ plans to explore the development of TPST-2003 to include patients with large B-cell lymphoma and other related indications; the planned advancement of a diversified next-generation CAR-T pipeline; anticipated therapeutic benefit and regulatory development of Tempest Therapeutics’ product candidates, including TPST-2003; and Tempest Therapeutics’ ability to achieve its operational plans. Any forward-looking statements in this press release are based on Tempest Therapeutics’ current expectations, estimates and projections about its industry as well as management’s current beliefs and expectations of future events only as of today and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to Tempest Therapeutics’ need for additional capital to fund its planned programs and operations and to continue to operate as a going concern; unexpected safety or efficacy data observed during preclinical or clinical trials; the possibility that results from prior clinical trials and preclinical studies may not necessarily be predictive of future results; past results may not be indicative of future results; clinical trial site activation or enrollment rates that are lower than expected; loss of key personnel; changes in expected or existing competition; changes in the regulatory environment; risks relating to volatility and uncertainty in the capital markets for biotechnology companies; and unexpected litigation or other disputes. These and other factors that may cause actual results to differ from those expressed or implied are discussed in greater detail in the “Risk Factors” section of Tempest’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2025, filed with the Securities and Exchange Commission (“SEC”) on November 5, 2025, and the “Risk Factors” section under Proposal 5 contained in Tempest’s definitive proxy statement on Schedule 14A, filed with the SEC on December 31, 2025, and in other documents filed by Tempest from time to time with the SEC. Except as required by applicable law, Tempest Therapeutics undertakes no obligation to revise or update any forward-looking statement, or to make any other forward-looking statements, whether as a result of new information, future events or otherwise. These forward-looking statements should not be relied upon as representing Tempest Therapeutics’ views as of any date subsequent to the date of this press release and should not be relied upon as prediction of future events. In light of the foregoing, investors are urged not to rely on any forward-looking statement in reaching any conclusion or making any investment decision about any securities of Tempest Therapeutics. Investor Contacts: Sylvia Wheeler Wheelhouse Life Science Advisors [email protected] Aljanae Reynolds Wheelhouse Life Science Advisors [email protected]

BRISBANE, Calif., Nov. 05, 2025 (GLOBE NEWSWIRE) -- Tempest Therapeutics, Inc. (Nasdaq: TPST), a clinical-stage biotechnology company with a pipeline of first-in-class1 targeted and immune-mediated therapeutics to fight cancer, today reported financial results for the quarter ended September 30, 2025 and provided a corporate update. “We are continuing our strategic alternatives process with the goal of maximizing value for stockholders,” said Stephen Brady, president and chief executive officer of Tempest. “In addition, we look forward to the start of the TPST-1495 Phase 2 in collaboration with the NCI and the Cancer Prevention Clinical Trials Network and remain confident in the potential of amezalpat to transform the treatment of first-line HCC and bring meaningful benefit to patients and their families.” —————— 1 If approved by the U.S. Food and Drug Administration (FDA). Financial Results Third Quarter 2025 Tempest ended the quarter with $7.5 million in cash and cash equivalents, compared to $30.3 million on December 31, 2024. The decrease was primarily due to cash used in operating activities, offset by $4.1 million in net proceeds from the June 2025 registered direct offering, as well as $2.8 million in net proceeds from the company’s at-the-market offering program. Net loss and net loss per share for the quarter were $3.5 million and $0.79, respectively, compared to $10.6 million and $5.32, respectively, for the same period in 2024. Research and development expenses for the quarter were $0.6 million, compared to $7.6 million for the same period in 2024. The $7.0 million decrease was primarily due to a decrease in costs incurred as a result of re-prioritizing efforts towards exploring strategic alternatives. General and administrative expenses for the quarter were $3.0 million, compared to $3.0 million for the same period in 2024, and were primarily related to consulting and professional services. Year-to-Date Cash used in operating activities for the nine months ended September 30, 2025 was $23.2 million. Net loss and net loss per share for the nine months ended September 30, 2025 were $22.2 million and $5.71, respectively, compared to $28.0 million and $15.48, respectively, for the same period in 2024. Research and development expenses for the nine months ended September 30, 2025 were $12.1 million, compared to $17.7 million for the same period in 2024. The $5.6 million decrease was primarily due to a decrease in costs incurred as a result of re-prioritizing efforts towards exploring strategic alternatives. General and administrative expenses for the nine months ended September 30, 2025 were $10.4 million, compared to $10.4 million for the same period in 2024, and were primarily related to employee compensation costs, inclusive of one-time separation costs for employees terminated during the nine months ended September 30, 2025, as well as consulting and professional services. About Tempest Therapeutics Tempest Therapeutics is a clinical-stage biotechnology company advancing a diverse portfolio of small molecule product candidates containing tumor-targeted and/or immune-mediated mechanisms with the potential to treat a wide range of tumors. Tempest is headquartered in Brisbane, California. More information about Tempest can be found on the company’s website at www.tempesttx.com. Forward-Looking Statements This press release contains forward-looking statements (including within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended, and Section 27A of the Securities Act of 1933, as amended (the “Securities Act”)) concerning Tempest Therapeutics, Inc. These statements may discuss goals, intentions, and expectations as to future plans, trends, events, results of operations or financial condition, or otherwise, based on current beliefs of the management of Tempest Therapeutics, as well as assumptions made by, and information currently available to, management of Tempest Therapeutics. Forward-looking statements contained in this press release include but are not limited to statements relating to Tempest Therapeutics’ evaluation of strategic alternatives available to the company to maximize value for stockholders and patients and anticipated therapeutic benefit and regulatory development of Tempest Therapeutics’ product candidates. Any forward-looking statements in this press release are based on Tempest Therapeutics’ current expectations, estimates and projections about its industry as well as management’s current beliefs and expectations of future events only as of today and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to, risks relating to volatility and uncertainty in the capital markets for biotechnology companies; Tempest Therapeutics’ ability to continue to operate as a going concern; availability of suitable third parties with which to conduct contemplated strategic transactions; whether we will be able to pursue a strategic transaction, or whether any transaction, if pursued, will be completed on attractive terms or at all; unexpected safety or efficacy data observed during preclinical or clinical trials; clinical trial site activation or enrollment rates that are lower than expected; changes in expected or existing competition; changes in the regulatory environment; and unexpected litigation or other disputes. These and other factors that may cause actual results to differ from those expressed or implied are discussed in greater detail in the “Risk Factors” section of the Company’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2025 and other documents filed by the Company from time to time with the Securities and Exchange Commission. Except as required by applicable law, Tempest Therapeutics undertakes no obligation to revise or update any forward-looking statement, or to make any other forward-looking statements, whether as a result of new information, future events or otherwise. These forward-looking statements should not be relied upon as representing Tempest Therapeutics’ views as of any date subsequent to the date of this press release and should not be relied upon as prediction of future events. In light of the foregoing, investors are urged not to rely on any forward-looking statement in reaching any conclusion or making any investment decision about any securities of Tempest Therapeutics. Investor Contacts: Sylvia Wheeler Wheelhouse Life Science Advisors [email protected] Aljanae Reynolds Wheelhouse Life Science Advisors [email protected]

Received clearance to proceed with pivotal trial of amezalpat combination therapy for first-line hepatocellular carcinoma (HCC) in China Granted orphan drug designation from the European Medicines Agency (EMA) for amezalpat for the treatment of patients with HCC Presented new amezalpat mechanism-of-action data reinforcing its potential as a novel cancer treatment at the 2025 AACR Annual Meeting Granted Orphan Drug designation by FDA for TPST-1495 for the treatment of familial adenomatous polyposis (FAP) BRISBANE, Calif., Aug. 11, 2025 (GLOBE NEWSWIRE) -- Tempest Therapeutics, Inc. (Nasdaq: TPST), a clinical-stage biotechnology company with a pipeline of first-in-class1 targeted and immune-mediated therapeutics to fight cancer, today reported financial results for the quarter ended June 30, 2025 and provided a corporate update. “We are pleased to see the continued progress of our clinical oncology portfolio, including the recent clearance in China to initiate a pivotal trial of amezalpat combination therapy in first-line HCC, expanding on similar clearances we received in the U.S. and Europe from the FDA and EMA,” said Stephen Brady, president and chief executive officer of Tempest. “We believe these milestones reflect both the promise of our therapies and the dedication of the team who brought the programs to this point. We remain actively engaged in our strategic alternatives process with the goal of maximizing value for stockholders and patients.” ____________________ 1 If approved by the U.S. Food and Drug Administration (FDA). Recent Highlights Amezalpat (TPST-1120) (clinical PPARα antagonist): Received clearance to proceed with pivotal trial of amezalpat combination therapy for first-line HCC in China. Granted orphan drug designation from the EMA for amezalpat for the treatment of patients with HCC. Reported new data at the 2025 American Association for Cancer Research (AACR) Annual Meeting, supporting the immune component of amezalpat’s dual mechanism of action and reinforcing its potential as a novel cancer treatment. Granted both Orphan Drug and Fast Track designations by the U.S. Food and Drug Administration (FDA) for amezalpat for the treatment of patients with HCC. TPST-1495 (clinical dual EP2/4 prostaglandin receptor antagonist): Granted Orphan Drug designation by the FDA to treat patients with FAP. Corporate: Announced cost-cutting measures and plans to explore a full range of strategic alternatives to advance the company’s promising clinical-stage programs and maximize stockholder value. Strengthened cash position with completion of $4.6 million registered direct offering of common stock in June 2025. Financial Results Second Quarter 2025 Tempest ended the quarter with $14.3 million in cash and cash equivalents, compared to $30.3 million on December 31, 2024. The decrease was primarily due to cash used in operating activities, offset by $4.1 million in net proceeds from the June 2025 registered direct offering, as well as $2.8 million in net proceeds from the company’s at-the-market offering program. Net loss and net loss per share for the quarter were $7.9 million and $2.07, respectively, compared to $9.6 million and $5.52, respectively, for the same period in 2024. Research and development expenses for the quarter were $3.9 million, compared to $5.8 million for the same period in 2024. The $1.9 million decrease was primarily due to a decrease in costs incurred as a result of re-prioritizing efforts towards exploring strategic alternatives. General and administrative expenses for the quarter were $4.1 million, compared to $3.7 million for the same period in 2024. The $0.4 million increase was primarily related to one-time separations costs for employees terminated during the period. Year-to-Date Cash used in operating activities for the six months ended June 30, 2025 was $16.5 million. Net loss and net loss per share for the six months ended June 30, 2025 were $18.7 million and $5.17, respectively, compared to $17.5 million and $10.15, respectively, for the same period in 2024. Research and development expenses for the six months ended June 30, 2025 were $11.5 million, compared to $10.2 million for the same period in 2024. The $1.3 million increase was primarily due to an increase in costs incurred from contract research and manufacturing organizations in preparation for the company’s pivotal Phase 3 trial of amezalpat for the treatment of first-line HCC. General and administrative expenses for the six months ended June 30, 2025 were $7.4 million, compared to $7.4 million for the same period in 2024, and were primarily related to employee compensation costs, inclusive of one-time separation costs for employees terminated during the quarter ended June 30, 2025, as well as consulting, professional services and facilities costs. About Tempest Therapeutics Tempest Therapeutics is a clinical-stage biotechnology company advancing a diverse portfolio of small molecule product candidates containing tumor-targeted and/or immune-mediated mechanisms with the potential to treat a wide range of tumors. The company’s novel programs range from early research to later-stage investigation in a randomized global study in first-line cancer patients. Tempest is headquartered in Brisbane, California. More information about Tempest can be found on the company’s website at www.tempesttx.com. Forward-Looking Statements This press release contains forward-looking statements (including within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended, and Section 27A of the Securities Act of 1933, as amended (the “Securities Act”)) concerning Tempest Therapeutics, Inc. These statements may discuss goals, intentions, and expectations as to future plans, trends, events, results of operations or financial condition, or otherwise, based on current beliefs of the management of Tempest Therapeutics, as well as assumptions made by, and information currently available to, management of Tempest Therapeutics. Forward-looking statements contained in this press release include but are not limited to statements relating to Tempest Therapeutics’ evaluation of strategic alternatives available to the company to maximize value for stockholders and patients and anticipated therapeutic benefit and regulatory development of Tempest Therapeutic’ product candidates. Any forward-looking statements in this press release are based on Tempest Therapeutics’ current expectations, estimates and projections about its industry as well as management’s current beliefs and expectations of future events only as of today and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to, risks relating to volatility and uncertainty in the capital markets for biotechnology companies; Tempest Therapeutics’ ability to continue to operate as a going concern; availability of suitable third parties with which to conduct contemplated strategic transactions; whether we will be able to pursue a strategic transaction, or whether any transaction, if pursued, will be completed on attractive terms or at all; unexpected safety or efficacy data observed during preclinical or clinical trials; clinical trial site activation or enrollment rates that are lower than expected; changes in expected or existing competition; changes in the regulatory environment; and unexpected litigation or other disputes. These and other factors that may cause actual results to differ from those expressed or implied are discussed in greater detail in the “Risk Factors” section of the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2025 and other documents filed by the Company from time to time with the Securities and Exchange Commission. Except as required by applicable law, Tempest Therapeutics undertakes no obligation to revise or update any forward-looking statement, or to make any other forward-looking statements, whether as a result of new information, future events or otherwise. These forward-looking statements should not be relied upon as representing Tempest Therapeutics’ views as of any date subsequent to the date of this press release and should not be relied upon as prediction of future events. In light of the foregoing, investors are urged not to rely on any forward-looking statement in reaching any conclusion or making any investment decision about any securities of Tempest Therapeutics. (1) Results have been adjusted to reflect the one-for-thirteen reverse stock split effected in April 2025. (1) Results have been adjusted to reflect the one-for-thirteen reverse stock split effected in April 2025. Investor Contacts: Sylvia Wheeler Wheelhouse Life Science Advisors [email protected] Aljanae Reynolds Wheelhouse Life Science Advisors [email protected] ____________________ i If approved by the FDA

Presented new amezalpat mechanism-of-action data reinforcing its potential as a novel cancer treatment at the 2025 AACR Annual Meeting Granted Orphan Drug designation by FDA for TPST-1495 for the treatment of familial adenomatous polyposis (FAP) Received FDA “Study May Proceed” letter for Phase 2 trial of TPST-1495 for the treatment of FAP Granted both Orphan Drug & Fast Track designations by FDA for Amezalpat (TPST-1120) for the treatment of patients with hepatocellular carcinoma (HCC) BRISBANE, Calif., May 13, 2025 (GLOBE NEWSWIRE) -- Tempest Therapeutics, Inc. (Nasdaq: TPST), a clinical-stage biotechnology company developing first-in-class1 targeted and immune-mediated therapeutics to fight cancer, today reported financial results for the quarter ended March 31, 2025 and provided a corporate update. “The amezalpat program continues to produce data that reinforce its potential as a cancer therapy, most recently in a presentation at AACR showing that amezalpat reduced immunosuppression and activated the immune system to attack tumors. We were pleased to present these data that elucidate one part of the amezalpat mechanism of action and support the positive randomized Phase 2 data, including the benefit seen in patients with markers of immune resistance,” said Stephen Brady, president and chief executive officer of Tempest. “We are actively engaged in exploring strategic alternatives to advance our promising clinical-stage programs and maximize stockholder value and, given the data, continue to have strong conviction in the potential of our oncology portfolio to drive meaningful impact for patients facing cancer.” ________________ 1 If approved by the U.S. Food and Drug Administration (FDA). Recent Highlights Amezalpat (TPST-1120) (clinical PPARα antagonist): Reported new data at the 2025 American Association for Cancer Research (AACR) Annual Meeting supporting the immune component of amezalpat’s dual mechanism of action and reinforcing its potential as a novel cancer treatment. Granted both Orphan Drug and Fast Track designations by the U.S. Food and Drug Administration (FDA) for amezalpat for the treatment of patients with HCC. TPST-1495 (clinical dual EP2/4 prostaglandin receptor antagonist): Granted Orphan Drug designation by the FDA to treat patients with FAP. Received a “Study May Proceed” letter from the FDA for the Phase 2 trial for the treatment of FAP. This trial, run by CP-CTNet and financially supported by the NCI’s Division of Cancer Prevention, underscores the urgent need for innovative cancer prevention strategies in high-risk patient populations. The Phase 2 study is expected to begin in 2025. Corporate: Announced (i) plans to explore a full range of strategic alternatives to advance the company’s promising clinical-stage programs and maximize stockholder value and (ii) a reduction in force that was completed on April 30, 2025. Using cash on hand, the company repaid $3.5 million in full satisfaction of Loan and Security Agreement with Oxford Finance LLC in April 2025. Financial Results First Quarter 2025 Tempest ended the quarter with $21.5 million in cash and cash equivalents, compared to $30.3 million on December 31, 2024. The decrease was primarily due to cash used in operating activities, offset by proceeds of $1.5 million from the at-the-market offering program. Net loss and net loss per share for the quarter were $10.9 million and $3.16, respectively, compared to $7.9 million and $4.62, respectively, for the same period in 2024. Research and development expenses for the quarter were $7.6 million compared to $4.3 million for the same period in 2024. The $3.3 million increase was primarily due to an increase in costs incurred from engaging contract research and manufacturing organizations in preparation for our pivotal Phase 3 trial of amezalpat for the treatment of first-line HCC. General and administrative expenses for the quarter were $3.3 million compared to $3.6 million for the same period in 2024. The $0.3 million decrease was primarily due to a decrease in consulting services. About Tempest Therapeutics Tempest Therapeutics is a clinical-stage biotechnology company advancing a diverse portfolio of small molecule product candidates containing tumor-targeted and/or immune-mediated mechanisms with the potential to treat a wide range of tumors. The company’s novel programs range from early research to later-stage investigation in a randomized global study in first-line cancer patients. Tempest is headquartered in Brisbane, California. More information about Tempest can be found on the company’s website at www.tempesttx.com. Forward-Looking Statements This press release contains forward-looking statements (including within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended, and Section 27A of the Securities Act of 1933, as amended (the “Securities Act”)) concerning Tempest Therapeutics, Inc. These statements may discuss goals, intentions, and expectations as to future plans, trends, events, results of operations or financial condition, or otherwise, based on current beliefs of the management of Tempest Therapeutics, as well as assumptions made by, and information currently available to, management of Tempest Therapeutics. Forward-looking statements contained in this press release include but are not limited to statements relating to Tempest Therapeutics’ evaluation of strategic alternatives available to the company to maximize stockholder value and anticipated therapeutic benefit and regulatory development of Tempest Therapeutic’ product candidates. Any forward-looking statements in this press release are based on Tempest Therapeutics’ current expectations, estimates and projections about its industry as well as management’s current beliefs and expectations of future events only as of today and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to, risks relating to volatility and uncertainty in the capital markets for biotechnology companies; Tempest Therapeutics’ ability to continue to operate as a going concern; availability of suitable third parties with which to conduct contemplated strategic transactions; whether we will be able to pursue a strategic transaction, or whether any transaction, if pursued, will be completed on attractive terms or at all; unexpected safety or efficacy data observed during preclinical or clinical trials; clinical trial site activation or enrollment rates that are lower than expected; changes in expected or existing competition; changes in the regulatory environment; and unexpected litigation or other disputes. These and other factors that may cause actual results to differ from those expressed or implied are discussed in greater detail in the “Risk Factors” section of the company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission (SEC) on March 27, 2025, as well as in other filings the company may make with the SEC in the future. Except as required by applicable law, Tempest Therapeutics undertakes no obligation to revise or update any forward-looking statement, or to make any other forward-looking statements, whether as a result of new information, future events or otherwise. These forward-looking statements should not be relied upon as representing Tempest Therapeutics’ views as of any date subsequent to the date of this press release and should not be relied upon as prediction of future events. In light of the foregoing, investors are urged not to rely on any forward-looking statement in reaching any conclusion or making any investment decision about any securities of Tempest Therapeutics. (1) Results have been adjusted to reflect the one-for-thirteen reverse stock split effected in April 2025. (1) Results have been adjusted to reflect the one-for-thirteen reverse stock split effected in April 2025. Investor Contacts: Sylvia Wheeler Wheelhouse Life Science Advisors [email protected] Aljanae Reynolds Wheelhouse Life Science Advisors [email protected]

• Granted Both Orphan Drug & Fast Track designations for Amezalpat (TPST-1120) for the treatment of patients with Hepatocellular Carcinoma (HCC) • Announced Agreement with Roche to Support Advancement of Amezalpat Combination Therapy into First-Line HCC Pivotal Trial • Received FDA “Study May Proceed” letter for Phase 2 trial of TPST-1495 for the treatment of Familial Adenomatous Polyposis (FAP) BRISBANE, Calif., March 27, 2025 (GLOBE NEWSWIRE) -- Tempest Therapeutics, Inc. (Nasdaq: TPST), a clinical-stage biotechnology company developing first-in-class1 targeted and immune-mediated therapeutics to fight cancer, today reported financial results for the year ended 2024 and provided a corporate update. “2024 was another year filled with significant progress and milestone achievements that position Tempest for a successful future,” said Stephen Brady, president and chief executive officer of Tempest. “Despite challenging capital markets, our lean team excelled, reporting key OS data from the ongoing randomized Phase 2 trial of amezalpat in first-line hepatocellular carcinoma. As previously announced, we have secured broad regulatory agreement with both the FDA and EMA on the Phase 3 plan and received both Orphan Drug and Fast Track designations from the FDA. We also advanced our second clinical program, TPST-1495, with a Phase 2 clinical trial for the treatment of patients with FAP, with data expected in 2026. Our focus remains on execution with excellence while securing the resources necessary to drive these promising drug candidates forward.” 2024 & Recent Accomplishments Amezalpat (TPST-1120) (clinical PPARα antagonist): Granted both Orphan Drug and Fast Track designations by the U.S. Food and Drug Administration (FDA) for amezalpat for the treatment of patients with HCC. Received a “Study May Proceed” letter from the FDA to evaluate amezalpat in combination with atezolizumab (TECENTRIQ®) and bevacizumab (Avastin®), the current standard of care for unresectable or metastatic HCC, in a pivotal Phase 3 trial for the first-line treatment of unresectable or metastatic HCC. Announced an agreement with F. Hoffmann-La Roche Ltd. (Roche) to advance the evaluation of amezalpat in combination with atezolizumab and bevacizumab into a pivotal Phase 3 trial for the first-line treatment of unresectable or metastatic HCC. Announced positive feedback from the end-of-Phase 2 meeting with the FDA for amezalpat in combination with atezolizumab and bevacizumab to treat first-line unresectable or metastatic HCC. Reported new positive survival data from the ongoing global randomized Phase 1b/2 clinical study demonstrating that amezalpat delivered a six-month improvement in median overall survival (OS) when combined with atezolizumab and bevacizumab in comparison to atezolizumab and bevacizumab alone, the standard of care, in the first-line treatment of patients with unresectable or metastatic HCC. Published positive data from Phase 1 trial of amezalpat in patients with advanced solid tumors in the Journal of Cancer Research Communications. Data showed that amezalpat demonstrated clinical activity, including tumor shrinkage, even in PD-1 inhibitor-refractory and immune-compromised cancers. These data complement the positive Phase 1b/2 data reported in October 2023 and June 2024 from a global randomized study of amezalpat in combination with atezolizumab and bevacizumab in first-line patients with advanced HCC. Reported new preclinical data at the 2024 American Association for Cancer Research (AACR) Annual Meeting demonstrating that amezalpat reduces kidney cancer growth as a monotherapy, while also showing increased inhibition when combined with frontline chemotherapy and immunotherapy. These data further support the clinical benefit observed in the amezalpat Phase 1 data presented in an oral presentation at ASCO 2022. TPST-1495 (clinical dual EP2/4 prostaglandin receptor antagonist) Received a “Study May Proceed” letter from the FDA to evaluate TPST-1495 in a Phase 2 Trial for the treatment of FAP. Corporate: Expanded leadership team to strengthen global clinical expertise with the appointments of Troy M. Wagner as Vice President of Quality Assurance and Sheldon Mullins as Vice President of Regulatory Affairs. Potential Future Milestones Amezalpat (TPST-1120) (clinical PPARα antagonist) Plan to advance amezalpat into a registrational study in first-line liver cancer patients, subject to obtaining additional resources. TPST-1495 (clinical dual EP2/4 prostaglandin receptor antagonist) Plan to advance TPST-1495 into a Phase 2 study in patients with FAP under the auspices of the Cancer Prevention Clinical Trials Network and funded by the National Cancer Institute (NCI) Division of Cancer Prevention in 2025, with data expected in 2026. Financial Results Year End 2024 Tempest ended the year with $30.3 million in cash and cash equivalents, compared to $39.2 million on December 31, 2023. The decrease was primarily due to cash used in operating activities, offset by proceeds from the issuance of common stock of $28.6 million from the at-the-market offering program. Net loss and net loss per share for the year were $41.8 million and $1.50, respectively, compared to $29.5 million and $1.91, respectively, for the same period in 2023. Research and development expenses for the year were $28.5 million compared to $17.5 million for the same period in 2023. The $11.0 million increase was primarily due to an increase in costs incurred from engaging contract research and manufacturing organizations in preparation for our pivotal Phase 3 trial of amezalpat for the treatment of first-line HCC. General and administrative expenses for the year were $13.6 million compared to $11.7 million for the same period in 2023. The $1.9 million increase was primarily due to an increase in stock-based compensation expense due to increased headcount as well as an increase in expenses related to legal and consulting services. About Tempest Therapeutics Tempest Therapeutics is a clinical-stage biotechnology company advancing a diverse portfolio of small molecule product candidates containing tumor-targeted and/or immune-mediated mechanisms with the potential to treat a wide range of tumors. The company’s novel programs range from early research to later-stage investigation in a randomized global study in first-line cancer patients. Tempest is headquartered in Brisbane, California. More information about Tempest can be found on the company’s website at www.tempesttx.com. Forward-Looking Statements This press release contains forward-looking statements (including within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended, and Section 27A of the Securities Act of 1933, as amended (the “Securities Act”)) concerning Tempest Therapeutics, Inc. These statements may discuss goals, intentions, and expectations as to future plans, trends, events, results of operations or financial condition, or otherwise, based on current beliefs of the management of Tempest Therapeutics, as well as assumptions made by, and information currently available to, management of Tempest Therapeutics. Forward-looking statements generally include statements that are predictive in nature and depend upon or refer to future events or conditions, and include words such as “may,” “will,” “should,” “would,” “could”, “expect,” “anticipate,” “plan,” “likely,” “believe,” “estimate,” “project,” “intend,” and other similar expressions. All statements that are not historical facts are forward-looking statements, including any statements regarding: the design, initiation, progress, timing, scope and results of clinical trials, including the anticipated Phase 3 study for amezalpat and Phase 2 Trial of TPST-1495; anticipated therapeutic benefit and regulatory development of the Company’s product candidates; the Company’s ability to advance into a late-stage clinical company; the Company’s ability to secure resources and funding; and the Company’s ability to achieve its operational plans. Forward-looking statements are based on information available to Tempest Therapeutics as of the date hereof and are not guarantees of future performance. Any factors may cause differences between current expectations and actual results, including: unexpected safety or efficacy data observed during preclinical or clinical trials; clinical trial site activation or enrollment rates that are lower than expected; changes in expected or existing competition; changes in the regulatory environment; and unexpected litigation or other disputes. Other factors that may cause actual results to differ from those expressed or implied are discussed in greater detail in the “Risk Factors” section of the Company’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2024 and other documents filed by the Company from time to time with the Securities and Exchange Commission. Except as required by applicable law, Tempest Therapeutics undertakes no obligation to revise or update any forward-looking statement, or to make any other forward-looking statements, whether as a result of new information, future events or otherwise. These forward-looking statements should not be relied upon as representing Tempest Therapeutics’ views as of any date subsequent to the date of this press release and should not be relied upon as prediction of future events. In light of the foregoing, investors are urged not to rely on any forward-looking statement in reaching any conclusion or making any investment decision about any securities of Tempest Therapeutics. Investor Contacts: Sylvia Wheeler Wheelhouse Life Science Advisors [email protected] Aljanae Reynolds Wheelhouse Life Science Advisors [email protected] 1 If approved by the U.S. Food and Drug Administration (FDA).