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
Rhea-AI Summary
OS Therapies (NYSE American: OSTX) received a U.S. FDA Type C Statistical Methods meeting to review 2.5‑year overall survival data from its Phase 2b OST‑HER2 trial in fully resected, pulmonary metastatic osteosarcoma. The meeting with CBER is expected in mid‑September 2026, alongside a pending CDER Biomarker Data Review Meeting.
The company plans to announce interim 3‑year overall survival data in early September 2026, which is expected to inform decisions on RMAT designation, FDA Rolling Review and a potential Biologics License Application under the Accelerated Approval Program by year‑end 2026. OS Therapies also obtained a parallel U.K. MHRA Scientific Advice Meeting in September 2026 on statistical methods for a Conditional Marketing Authorisation Application leveraging 2.5‑year survival data.
Positive
- FDA Type C Statistical Methods meeting granted for 2.5-year OST-HER2 survival data, expected mid-September 2026
- Interim 3-year overall survival readout for OST-HER2 anticipated in early September 2026
- Parallel MHRA Scientific Advice Meeting in September 2026 to support U.K. Conditional Marketing Authorisation Application
- OST-HER2 Phase 2b trial showed clinically significant benefit in 12-month event-free survival and overall survival endpoints
- Multiple regulatory designations for OST-HER2, including FDA ODD, FTD, RPDD and EMA/MHRA ODD, FTD, ATMP
- Potential Priority Review Voucher eligibility if OST-HER2 receives a U.S. BLA approval under the Rare Pediatric Disease program
Negative
- None.
News Explained
The granted FDA Type C meeting remains a planned
Key Figures
Historical Context
| Date | Event | Sentiment | 24h Move | Catalyst |
|---|---|---|---|---|
| Jul 08 | FDA meeting update | Positive | -8.2% | FDA biomarker meeting accepted alongside statistical methods meeting for survival data |
| Jul 06 | Q3 outlook | Positive | -14.8% | Regulatory milestones, financing and cash runway were highlighted in the corporate outlook |
| Jul 02 | Board and financing | Positive | +4.4% | Director appointment and $10 million line of credit accompanied development plans |
| Jun 30 | U.S. regulatory update | Positive | -15.2% | FDA meeting request and accelerated approval strategy were outlined for OST-HER2 |
| Jun 26 | Clinical trial data | Positive | +4.4% | Canine study reported 159-day median survival versus 124 days with radiation alone |
24h Move is the share-price change in the day after each event; other market factors may also have contributed.
Recent positive regulatory and outlook announcements were followed by declines, while management and clinical updates were followed by gains.
Key Terms
type c statistical methods meeting regulatory
overall survival medical
rmat designation regulatory
rolling review regulatory
conditional marketing authorisation application regulatory
AI-generated analysis. How Rhea-AI works. Not financial advice.
- Meeting to occur in mid-September 2026
- Interim 3-year Overall Survival data expected early September, 2026
- Decisions on appropriate comparator arm to interpret OST-HER2 clinical efficacy, RMAT designation and Rolling Review expected following this meeting
- Sustained overall survival benefit observed between 2-year and 2.5-year timepoints
- U.K. MHRA Statistical Methods Scientific Advice Meeting granted in parallel
New York, New York and Rockville, Maryland--(Newsfile Corp. - August 13, 2026) - OS Therapies, Inc. (NYSE American: OSTX) ("OS Therapies" or "the Company"), 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.
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.
"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."
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.
About OS Therapies
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 & Drug Administration and has received ODD, FTD and Advanced Therapy Medicinal Products (ATMP) from the European Medicines Agency.
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.
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 www.ostherapies.com.
Forward-Looking Statements
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.
OS Therapies Contact Information:
Investor Relations
Harrison Seidner, PhD
WaterSeid Partners
OSTX@waterseid.com
Public Relations
Stephanie Chen
Elev8 New Media
media@ostherapies.com
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