OS Therapies Announces FDA PDUFA Waiver & EMA Grants Union Marketing Authorisation Eligibility
Rhea-AI Summary
OS Therapies (NYSE American: OSTX) announced regulatory progress for OST-HER2 and its Metastatic Osteosarcoma Program on December 5, 2025.
The U.S. FDA granted a waiver of the BLA application fee for BLA 125867 (OST-HER2). The EMA CHMP granted Union Marketing Authorisation eligibility for OST-HER2 in prevention or delay of recurrent, fully‑resected pulmonary metastatic osteosarcoma and requested an accelerated MAA submission by February 28, 2026. The company completed pre-meeting submissions to the UK MHRA for a pre‑MAA meeting on Dec 8, 2025 and scheduled a Type C meeting with the FDA on Dec 11, 2025. OS Therapies intends to review commercial CMC, non‑clinical considerations, and propose a global confirmatory study to support conditional/accelerated approvals.
Positive
- FDA granted a waiver of the BLA application fee for BLA 125867
- EMA CHMP granted Union Marketing Authorisation eligibility for OST-HER2
- EMA requested an accelerated MAA submission by Feb 28, 2026
- Completed pre‑meeting submissions to MHRA for Dec 8, 2025 meeting
Negative
- Accelerated MAA deadline (Feb 28, 2026) may compress submission timeline
- Regulatory approvals conditioned on confirmatory/global study design and CMC
News Market Reaction – OSTX
In the Dec 5 session, OSTX gained 5.49%, reflecting a notable positive market reaction. Our momentum scanner triggered 3 alerts that day, indicating moderate trading interest and price volatility. Trading volume was elevated at 2.0x the daily average, suggesting notable buying interest.
Data tracked by StockTitan Argus on the day of publication.
Key Figures
Historical Context
| Date | Event | Sentiment | 24h Move | Catalyst |
|---|---|---|---|---|
| Nov 25 | Naming / regulatory | Positive | +4.7% | WHO assigned INN ‘daznelimgene lisbac’ and timelines for regulatory filings. |
| Nov 21 | Coverage update | Positive | +5.6% | Analyst update highlighting strong Phase 2b survival and financing runway extension. |
| Nov 20 | Spinoff announcement | Positive | -1.8% | Plan to spin off OS Animal Health and outline veterinary OST-HER2 market potential. |
| Nov 17 | Earnings / update | Positive | -5.0% | Q3 2025 results with positive OST-HER2 data, regulatory timelines, and new financing. |
| Oct 22 | Clinical data | Positive | +1.7% | Phase 2b subgroup OS/EFS data showing strong survival versus natural history. |
24h Move is the share-price change in the day after each event; other market factors may also have contributed.
Recent OSTX news has often been positive clinically/regulatorily, but price reactions have been mixed with both rallies and sell-the-news responses.
Over the past six weeks, OS Therapies has steadily advanced OST-HER2 toward commercialization. On Oct 22, 2025, it reported favorable Phase 2b subgroup survival data. Subsequent Q3 2025 results highlighted strong efficacy and outlined BLA/MAA timelines. In late November, coverage updates and the WHO nonproprietary name “daznelimgene lisbac” reinforced regulatory momentum, with multiple items noting planned filings in January 2026. Today’s announcement of an FDA BLA fee waiver and EMA Union Marketing Authorisation eligibility fits this ongoing regulatory progression.
Key Terms
pdufa regulatory
marketing authorisation application regulatory
chmp regulatory
conditional approval regulatory
accelerated approval regulatory
cmc technical
AI-generated analysis. How Rhea-AI works. Not financial advice.
- U.S. FDA grants waiver of application fee for BLA Filing of OST-HER2
- Scheduled pre-Marketing Authorisation Application meeting with United Kingdom's Medicines and Healthcare products Regulatory Agency on December 8, 2025
- Scheduled Type C Meeting with United States Food & Drug Administration on December 11, 2025
New York, New York--(Newsfile Corp. - December 5, 2025) - OS Therapies Inc. (NYSE American: OSTX) ("OS Therapies" or "the Company"), the world leader in listeria-based cancer immunotherapies, today announced the United States Food & Drug Administration (FDA) granted the Company waiver of the application fee for BLA 125867 for OST-HER2.
Additionally, the European Medicines Agency (EMA) Committee for Medicinal Products for Human Use ('CHMP') granted Union Marketing Authorisation eligibility for OST-HERs in the prevention or delay of recurrent, fully-resected, pulmonary metastatic osteosarcoma (the 'Metastatic Osteosarcoma Program'). EMA CHMP requested an accelerated Marketing Authorisation Application ('MAA') submission for the Metastatic Osteosarcoma Program by February 28, 2026. The intent of the European Union-wide Centralised Procedure is to support the marketing authorization of medicines, where there is a single application, a single evaluation and a single authorization for all EU Member States.
Concurrent with this announcement, the Company has completed pre-meeting submissions to the United Kingdom's Medicines and Healthcare products Regulatory Agency (MHRA) for its pre-MAA meeting on December 8, 2025 and its Type C Meeting with the FDA on December 11, 2025. The Company intends to review final commercial CMC and non-clinical considerations, as well as propose the global confirmatory study design to support an MAA Conditional Approval from MHRA, and a Biologics Licensing Application (BLA) under the Accelerated Approval Program ('Accelerated Approval') from FDA, respectively.
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 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 has received Rare Pediatric Disease Designation (RPDD) from the U.S. Food & Drug Administration and Fast-Track and Orphan Drug designations from the U.S. FDA and European Medicines Agency. The Company reported positive data in its Phase 2b clinical trial of OST-HER2 in recurrent, fully resected, lung metastatic osteosarcoma, demonstrating statistically significant benefit in the 12-month event free survival (EFS) primary endpoint of the study. The Company anticipates submitting a Biologics Licensing Application (BLA) to the U.S. FDA for OST-HER2 in osteosarcoma in early 2026 and, if approved, would become eligible to receive a Priority Review Voucher that it could then sell. 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 been conditionally approved by the U.S. Department of Agriculture for the treatment of canines with osteosarcoma.
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 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, most recent Quarterly Report on Form 10-Q 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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To view the source version of this press release, please visit https://www.newsfilecorp.com/release/277041