Meeting to occur in mid-September 2026Interim 3-year Overall Survival data expected early September, 2026Decisions on appropriate comparator arm to interpret OST-HER2 clinical efficacy, RMAT designation and Rolling

<ul style="list-style-type: disc;"><li><i>Meeting to occur in mid-September 2026</i></li><li><i>Interim 3-year Overall Survival data expected early September, 2026</i></li><li><i>Decisions on appropriate comparator arm to interpret OST-HER2 clinical efficacy, RMAT designation and Rolling Review expected following this meeting</i></li><li><i>Sustained overall survival benefit observed between 2-year and 2.5-year timepoints</i></li><li><i>U.K. MHRA Statistical Methods Scientific Advice Meeting granted in parallel</i></li></ul><p>New York, New York and Rockville, Maryland--(Newsfile Corp. - August 13, 2026) - <b>OS Therapies, Inc. (NYSE:<a class="ticker" href="https://www.benzinga.com/quote/OSTX">OSTX</a>) ("OS Therapies" or "the Company")</b>, the world leader in gene-edited, Listeria-based cancer immunotherapies, today announced that the U.S. Food and Drug Administration (FDA) has granted the Company's requested Type C Statistical Methods meeting to review the 2.5 year overall survival data from the Phase 2b trial of OST-HER2 in the prevention of recurrence in fully resected, pulmonary metastatic osteosarcoma (the "Metastatic Osteosarcoma Trial"). The Company expects the FDA Type C Statistical Methods Meeting to occur in mid-September 2026 with members from division within the Center for Biologics Evaluation and Research (CBER), in parallel with the pending Biomarker Data Review Meeting being scheduled with members of the Center for Drug Evaluation and Research's (CDER) Biomarker Qualification Program (BQP). CBER is ultimately responsible for granting regulatory approval for gene-edited products such as OST-HER2. The Company expects to announce interim 3-year overall survival data in early September 2026.</p><p>Concurrent with this announcement, the U.K. Medicines and Healthcare products Regulatory Agency (MHRA) has granted a new Scientific Advice Meeting (SAM) to review the statistical methods that will be used to support the Company's pending Conditional Marketing Authorisation Application (CMAA) submission, including whether the Company can finalize its U.K. CMAA submission leveraging 2.5-year overall survival. This meeting is expected to occur in September 2026.</p><p>"We expect this Type C Statistics Methods Meeting with FDA to focus on the appropriateness of using pooled non-concurrent published historical control data, as compared with concurrent natural history data generated via OST-400, to evaluate the clinical efficacy data generated from the OST-HER2 Metastatic Osteosarcoma Trial," said Dr. Craig Eagle, Chief Medical Advisor and member of the OS Therapies Board of Directors. "We are heartened that overall survival at the 2.5-year timepoint remained unchanged from the 2-year timepoint. We look forward to the interim 3-year overall survival data in early September 2026, that will allow for decisions on our pending Regenerative Medicine Advanced Therapy (RMAT) designation submission, FDA Rolling Review and Commissioner's National Priority Review Voucher more rapidly to facilitate a potential Biologics License Application under the Accelerated Approval Program by year end 2026."</p><p>OST-HER2 has received Orphan Drug Designation (ODD), Fast Track Designation (FTD) and Rare Pediatric Disease Designation (RPDD) from the FDA, and ODD, FTD and ATMP from the EMA and MHRA. Under the RPDD FDA program, if the Company receives a BLA in the United States, it will become eligible to receive a Priority Review Voucher (PRV) that it intends to sell. The Company's Commissioner's National Priority Review Voucher (CNPV) letter of intent was accepted by FDA, with a final decision expected following full submission of the OST-HER2 BLA. The Company is seeking to obtain a BLA under the Accelerated Approval Program for OST-HER2 in osteosarcoma by year-end 2026 in the U.S., in addition to Conditional Marketing Authorisation Applications in Europe, the U.K. and Australia.</p><p><b>About OS Therapies</b><br />OS Therapies is a clinical stage oncology company focused on the identification, development, and commercialization of treatments for Osteosarcoma (OS) and other solid tumors. The Company is the world leader in gene-edited, Listeria-based cancer immunotherapies. OST-HER2, the Company's lead asset, is an immunotherapy leveraging the immune-stimulatory effects of Listeria bacteria to initiate a strong immune response targeting the HER2 protein. OST-HER2 is designed to target two mutated extracellular epitopes and one mutated intracellular epitope of the HER2 oncogene, requiring only one of these three epitopes to be present in a tumor (or micro-metastasis) to trigger the desired immune response. OST-HER2 has received Orphan Drug Designation (ODD), Fast Track Designation (FTD) and Rare Pediatric Disease Designation (RPDD) from the U.S. Food &#38; Drug Administration and has received ODD, FTD and Advanced Therapy Medicinal Products (ATMP) from the European Medicines Agency. </p><p>The Company reported positive data in its Phase 2b clinical trial of OST-HER2 in the prevention or delay of recurrence in fully resected, pulmonary metastatic osteosarcoma, demonstrating clinically significant benefit in the 12-month event free survival (EFS) primary endpoint of the study and the overall survival (OS) secondary endpoint. The Company is seeking a Biologics License Application (BLA) from the U.S. FDA for OST-HER2 in osteosarcoma in 2026 and, if approved, would become eligible to receive a Priority Review Voucher that it could then sell. The Company also anticipates receiving Conditional Marketing Authorisation Applications from the U.K.'s Medicines and Healthcare products Regulatory Agency and the EMA for OST-HER2 in 2026. OST-HER2 has completed a Phase 1 clinical study primarily in breast cancer patients, in addition to showing preclinical efficacy data in various models of breast cancer. OST-HER2 has previously been conditionally approved by the U.S. Department of Agriculture for the treatment of canines with osteosarcoma. The Company has also completed dosing in a Phase 1 study of OST-504 for castration-resistant prostate cancer. </p><p>In addition, OS Therapies is advancing its next-generation Antibody Drug Conjugate (ADC) and Drug Conjugates (DC), known as tunable ADC (tADC), which features tunable, tailored antibody-linker-payload candidates. This platform leverages the Company's proprietary silicone Si-Linker and Conditionally Active Payload (CAP) technology, enabling the delivery of multiple payloads per linker. For more information, please visit <a href="https://api.newsfilecorp.com/redirect/jNrDWFrVXM">www.ostherapies.com</a>. </p><p><b>Forward-Looking Statements</b></p><p>Statements in this press release about future expectations, plans and prospects, as well as any other statements regarding matters that are not historical facts, may constitute forward-looking statements within the meaning of the federal securities laws. These forward-looking statements and terms such as "anticipate," "expect," "intend," "may," "will," "should" or other comparable terms involve risks and uncertainties because they relate to events and depend on circumstances that will occur in the future. Those statements include statements regarding the intent, belief or current expectations of OS Therapies and members of its management, as well as the assumptions on which such statements are based. OS Therapies cautions readers that forward-looking statements are based on management's expectations and assumptions as of the date of this press release and are subject to certain risks and uncertainties that could cause actual results to differ materially, including, but not limited to the potential approval of OST-HER2 by the U.S. FDA and other risks and uncertainties described in "Risk Factors" in the Company's most recent Annual Report on Form 10-K and other subsequent documents the Company files with the Securities and Exchange Commission. Any forward-looking statements contained in this press release speak only as of the date hereof, and, except as required by the federal securities laws, OS Therapies specifically disclaims any obligation to update any forward-looking statement, whether as a result of new information, future events or otherwise.</p><div id="contactInfo"><p><b>OS Therapies Contact Information:</b><br /><br />Investor Relations<br />Harrison Seidner, PhD<br />WaterSeid Partners<br /><a href="mailto:OSTX@waterseid.com">OSTX@waterseid.com</a> </p><p>Public Relations<br />Stephanie Chen<br />Elev8 New Media<br /><a href="mailto:media@ostherapies.com">media@ostherapies.com</a></p></div><p><a href="https://api.newsfilecorp.com/redirect/vE5BbSDyGg">https://x.com/OSTherapies</a><br /><a href="https://api.newsfilecorp.com/redirect/JkRjosArxv">https://www.instagram.com/ostherapies/</a><br /><a href="https://api.newsfilecorp.com/redirect/GzpVBcyNwN">https://www.facebook.com/OSTherapies/</a><br /><a href="https://api.newsfilecorp.com/redirect/Q2zB0C7GnN">https://www.linkedin.com/company/os-therapies/</a></p><p id="corporateNewsLogoContainer"><img src="https://images.newsfilecorp.com/files/11596/309477_0fcaa44f748f399f_logo.jpg" id="corporateNewsLogo" alt="Corporate Logo" /></p><p id="corporateLinkBack">To view the source version of this press release, please visit <a href="https://api.newsfilecorp.com/redirect/mj4zbh4G8V">https://www.newsfilecorp.com/release/309477</a></p><p><img src="https://api.newsfilecorp.com/newsinfo/309477/197" alt="" /></p>

OSTX

OS Therapies Granted U.S. FDA Type C Statistical Methods Meeting to Review 2.5-Year Overall Survival Data for OST-HER2 in the Prevention or Delay of Recurrence in Fully Resected, Pulmonary Metastatic Osteosarcoma

OST Therapies moves closer to RMAT and BLA with stable OS

<section class="insight" data-version="1">
  <section data-block="information">
    <h3>Information</h3>
    <p>Meeting to occur in mid-September 2026Interim 3-year Overall Survival data expected early September, 2026Decisions on appropriate comparator arm to interpret OST-HER2 clinical efficacy, RMAT designation and Rolling</p>
  </section>

  <section data-block="ai-summary-paragraph">
    <h3>AI Summary</h3>
    <p>OS Therapies reports an FDA Type C statistical methods meeting for OST-HER2, with 2.5-year OS data due for review in Sept 2026, alongside UK MHRA SAM. Interim 3-year OS data is expected in early Sept 2026, potentially enabling RMAT designation and FDA Rolling Review, which could accelerate a BLA by year-end if efficacy holds.</p>
  </section>

  <section data-block="ai-summary-bullets">
    <h3>Key Points</h3>
    <ul><li>FDA grants Type C meeting to review OST-HER2 2.5-year OS data; mid-Sept 2026.</li><li>Interim 3-year OS data anticipated early Sept 2026; RMAT and Rolling Review decisions follow.</li><li>UK MHRA SAM granted in parallel; CMAA submission timing tied to 2.5-year OS.</li><li>OS Therapies cites sustained OS from 2-year to 2.5-year; potential BLA by year-end.</li></ul>
  </section>

  <section data-block="companies-mentioned">
    <h3>Companies Mentioned</h3>
    <ul><li><strong>OS Therapies, Inc. (OSTX)</strong>: Regulatory catalysts: Type C FDA meeting, 2.5-year OS data, potential year-end BLA.</li><li><strong>U.S. Food and Drug Administration (FDA)</strong>: Regulatory body overseeing Type C meeting; accelerates pathway if data consistent.</li><li><strong>MHRA (Medicines and Healthcare products Regulatory Agency) (MHRA)</strong>: UK SAM for CMAA review; September 2026 meeting enhances EU/UK path.</li><li><strong>European Medicines Agency (EMA)</strong>: Designations and CMAA considerations; EU market approval potential in 2026.</li></ul>
  </section>

  <section data-block="category">
    <h3>Industry News</h3>
    <p>Category Type: Industry News. Regulatory and data milestones directly affect OSTX&#039;s approval trajectory and valuation.</p>
  </section>

  <section data-block="market-moving">
    <h3>Market-Moving</h3>
    <ul><li>FDA Type C meeting scheduled in Sept 2026 to review OST-HER2 2.5-year OS.</li><li>Interim 3-year OS data due early Sept 2026.</li><li>UK MHRA SAM for CMAA submission to occur in Sept 2026.</li><li>RMAT designation and FDA Rolling Review could accelerate U.S. approval timeline.</li></ul>
  </section>

  <section data-block="key-facts">
    <h3>Key Facts</h3>
    <ul><li>Meeting mid-September 2026 with FDA’s CBER/CDER on OST-HER2 data.</li><li>Interim 3-year OS data expected in early September 2026.</li><li>2.5-year OS data reportedly unchanged from 2-year timepoint.</li><li>UK MHRA SAM granted in parallel for CMAA review in September 2026.</li><li>OST-HER2 has FDA ODD, FTD, RPDD; EMA ODD/FTD/ATMP designations.</li></ul>
  </section>

  <section data-block="trading-thesis">
    <h3>Trading Thesis</h3>
    <p>Bullish OSTX on regulatory momentum; expect upside into Sept milestones and potential year-end BLA.</p>
  </section>
</section>


<ul style="list-style-type: disc;"><li><i>Meeting to occur in mid-September 2026</i></li><li><i>Interim 3-year Overall Survival data expected early September, 2026</i></li><li><i>Decisions on appropriate comparator arm to interpret OST-HER2 clinical efficacy, RMAT designation and Rolling Review expected following this meeting</i></li><li><i>Sustained overall survival benefit observed between 2-year and 2.5-year timepoints</i></li><li><i>U.K. MHRA Statistical Methods Scientific Advice Meeting granted in parallel</i></li></ul><p>New York, New York and Rockville, Maryland--(Newsfile Corp. - August 13, 2026) - <b>OS Therapies, Inc. (NYSE:<a class="ticker" href="https://www.benzinga.com/quote/OSTX">OSTX</a>) ("OS Therapies" or "the Company")</b>, the world leader in gene-edited, Listeria-based cancer immunotherapies, today announced that the U.S. Food and Drug Administration (FDA) has granted the Company's requested Type C Statistical Methods meeting to review the 2.5 year overall survival data from the Phase 2b trial of OST-HER2 in the prevention of recurrence in fully resected, pulmonary metastatic osteosarcoma (the "Metastatic Osteosarcoma Trial"). The Company expects the FDA Type C Statistical Methods Meeting to occur in mid-September 2026 with members from division within the Center for Biologics Evaluation and Research (CBER), in parallel with the pending Biomarker Data Review Meeting being scheduled with members of the Center for Drug Evaluation and Research's (CDER) Biomarker Qualification Program (BQP). CBER is ultimately responsible for granting regulatory approval for gene-edited products such as OST-HER2. The Company expects to announce interim 3-year overall survival data in early September 2026.</p><p>Concurrent with this announcement, the U.K. Medicines and Healthcare products Regulatory Agency (MHRA) has granted a new Scientific Advice Meeting (SAM) to review the statistical methods that will be used to support the Company's pending Conditional Marketing Authorisation Application (CMAA) submission, including whether the Company can finalize its U.K. CMAA submission leveraging 2.5-year overall survival. This meeting is expected to occur in September 2026.</p><p>"We expect this Type C Statistics Methods Meeting with FDA to focus on the appropriateness of using pooled non-concurrent published historical control data, as compared with concurrent natural history data generated via OST-400, to evaluate the clinical efficacy data generated from the OST-HER2 Metastatic Osteosarcoma Trial," said Dr. Craig Eagle, Chief Medical Advisor and member of the OS Therapies Board of Directors. "We are heartened that overall survival at the 2.5-year timepoint remained unchanged from the 2-year timepoint. We look forward to the interim 3-year overall survival data in early September 2026, that will allow for decisions on our pending Regenerative Medicine Advanced Therapy (RMAT) designation submission, FDA Rolling Review and Commissioner's National Priority Review Voucher more rapidly to facilitate a potential Biologics License Application under the Accelerated Approval Program by year end 2026."</p><p>OST-HER2 has received Orphan Drug Designation (ODD), Fast Track Designation (FTD) and Rare Pediatric Disease Designation (RPDD) from the FDA, and ODD, FTD and ATMP from the EMA and MHRA. Under the RPDD FDA program, if the Company receives a BLA in the United States, it will become eligible to receive a Priority Review Voucher (PRV) that it intends to sell. The Company's Commissioner's National Priority Review Voucher (CNPV) letter of intent was accepted by FDA, with a final decision expected following full submission of the OST-HER2 BLA. The Company is seeking to obtain a BLA under the Accelerated Approval Program for OST-HER2 in osteosarcoma by year-end 2026 in the U.S., in addition to Conditional Marketing Authorisation Applications in Europe, the U.K. and Australia.</p><p><b>About OS Therapies</b><br />OS Therapies is a clinical stage oncology company focused on the identification, development, and commercialization of treatments for Osteosarcoma (OS) and other solid tumors. The Company is the world leader in gene-edited, Listeria-based cancer immunotherapies. OST-HER2, the Company's lead asset, is an immunotherapy leveraging the immune-stimulatory effects of Listeria bacteria to initiate a strong immune response targeting the HER2 protein. OST-HER2 is designed to target two mutated extracellular epitopes and one mutated intracellular epitope of the HER2 oncogene, requiring only one of these three epitopes to be present in a tumor (or micro-metastasis) to trigger the desired immune response. OST-HER2 has received Orphan Drug Designation (ODD), Fast Track Designation (FTD) and Rare Pediatric Disease Designation (RPDD) from the U.S. Food &#38; Drug Administration and has received ODD, FTD and Advanced Therapy Medicinal Products (ATMP) from the European Medicines Agency. </p><p>The Company reported positive data in its Phase 2b clinical trial of OST-HER2 in the prevention or delay of recurrence in fully resected, pulmonary metastatic osteosarcoma, demonstrating clinically significant benefit in the 12-month event free survival (EFS) primary endpoint of the study and the overall survival (OS) secondary endpoint. The Company is seeking a Biologics License Application (BLA) from the U.S. FDA for OST-HER2 in osteosarcoma in 2026 and, if approved, would become eligible to receive a Priority Review Voucher that it could then sell. The Company also anticipates receiving Conditional Marketing Authorisation Applications from the U.K.'s Medicines and Healthcare products Regulatory Agency and the EMA for OST-HER2 in 2026. OST-HER2 has completed a Phase 1 clinical study primarily in breast cancer patients, in addition to showing preclinical efficacy data in various models of breast cancer. OST-HER2 has previously been conditionally approved by the U.S. Department of Agriculture for the treatment of canines with osteosarcoma. The Company has also completed dosing in a Phase 1 study of OST-504 for castration-resistant prostate cancer. </p><p>In addition, OS Therapies is advancing its next-generation Antibody Drug Conjugate (ADC) and Drug Conjugates (DC), known as tunable ADC (tADC), which features tunable, tailored antibody-linker-payload candidates. This platform leverages the Company's proprietary silicone Si-Linker and Conditionally Active Payload (CAP) technology, enabling the delivery of multiple payloads per linker. For more information, please visit <a href="https://api.newsfilecorp.com/redirect/jNrDWFrVXM">www.ostherapies.com</a>. </p><p><b>Forward-Looking Statements</b></p><p>Statements in this press release about future expectations, plans and prospects, as well as any other statements regarding matters that are not historical facts, may constitute forward-looking statements within the meaning of the federal securities laws. These forward-looking statements and terms such as "anticipate," "expect," "intend," "may," "will," "should" or other comparable terms involve risks and uncertainties because they relate to events and depend on circumstances that will occur in the future. Those statements include statements regarding the intent, belief or current expectations of OS Therapies and members of its management, as well as the assumptions on which such statements are based. OS Therapies cautions readers that forward-looking statements are based on management's expectations and assumptions as of the date of this press release and are subject to certain risks and uncertainties that could cause actual results to differ materially, including, but not limited to the potential approval of OST-HER2 by the U.S. FDA and other risks and uncertainties described in "Risk Factors" in the Company's most recent Annual Report on Form 10-K and other subsequent documents the Company files with the Securities and Exchange Commission. Any forward-looking statements contained in this press release speak only as of the date hereof, and, except as required by the federal securities laws, OS Therapies specifically disclaims any obligation to update any forward-looking statement, whether as a result of new information, future events or otherwise.</p><div id="contactInfo"><p><b>OS Therapies Contact Information:</b><br /><br />Investor Relations<br />Harrison Seidner, PhD<br />WaterSeid Partners<br /><a href="mailto:OSTX@waterseid.com">OSTX@waterseid.com</a> </p><p>Public Relations<br />Stephanie Chen<br />Elev8 New Media<br /><a href="mailto:media@ostherapies.com">media@ostherapies.com</a></p></div><p><a href="https://api.newsfilecorp.com/redirect/vE5BbSDyGg">https://x.com/OSTherapies</a><br /><a href="https://api.newsfilecorp.com/redirect/JkRjosArxv">https://www.instagram.com/ostherapies/</a><br /><a href="https://api.newsfilecorp.com/redirect/GzpVBcyNwN">https://www.facebook.com/OSTherapies/</a><br /><a href="https://api.newsfilecorp.com/redirect/Q2zB0C7GnN">https://www.linkedin.com/company/os-therapies/</a></p><p id="corporateNewsLogoContainer"><img src="https://images.newsfilecorp.com/files/11596/309477_0fcaa44f748f399f_logo.jpg" id="corporateNewsLogo" alt="Corporate Logo" /></p><p id="corporateLinkBack">To view the source version of this press release, please visit <a href="https://api.newsfilecorp.com/redirect/mj4zbh4G8V">https://www.newsfilecorp.com/release/309477</a></p><p><img src="https://api.newsfilecorp.com/newsinfo/309477/197" alt="" /></p>

OS Therapies reports an FDA Type C statistical methods meeting for OST-HER2, with 2.5-year OS data due for review in Sept 2026, alongside UK MHRA SAM. Interim 3-year OS data is expected in early Sept 2026, potentially enabling RMAT designation and FDA Rolling Review, which could accelerate a BLA by year-end if efficacy holds.

os-therapies-granted-u-s-fda-type-c-statistical-methods-meeting-to-review-2-5-year-overall-survival-data-for-ost-her2-in-the-prevention-or-delay-of-recurrence-in-fully-resected-pulmonary-metastatic-osteosarcoma

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OS Therapies Granted U.S. FDA Type C Statistical Methods Meeting to Review 2.5-Year Overall Survival Data for OST-HER2 in the Prevention or Delay of Recurrence in Fully Resected, Pulmonary Metastatic Osteosarcoma

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