OS Therapies Provides Positive EMA Regulatory Update Following Positive Rapporteur Meeting
OS Therapies (NYSE: OSTX) reported a positive regulatory update after an October 6, 2025 meeting with the EMA rapporteur (MEB). The rapporteur indicated that overall survival (OS) with statistically significant, final two-year results may serve as a primary endpoint for a conditional marketing authorization (CMA). The rapporteur viewed safety, non-clinical, and CMC data as sufficient to support a CMA submission. The meeting advances formal EMA Scientific Advice expected in December 2025 and established a pathway for a confirmatory randomized program and potential label expansion. The UK MHRA granted an expedited Market Access Scientific Advice meeting to support the MAA process.
OS Therapies (NYSE: OSTX) ha riportato un aggiornamento regolatorio positivo dopo un incontro del 6 ottobre 2025 con il relatore dell'EMA (MEB). Il relatore ha indicato che sopravvivenza globale (OS) con risultati finali di due anni, statisticamente significativi, potrebbe fungere da endpoint primario per una autorizzazione all'immissione in commercio condizionata (CMA). Il relatore ha ritenuto che i dati di sicurezza, non clinici e di CMC siano sufficienti a supportare una presentazione CMA. L'incontro accelera l'Adozione Scientifica formale dell'EMA prevista per dicembre 2025 e ha stabilito un percorso per un programma di conferma randomizzato e un potenziale ampliamento dell'etichetta. La MHRA del Regno Unito ha concesso un incontro accelerato di Market Access Scientific Advice per supportare il processo di MAA.
OS Therapies (NYSE: OSTX) informó de una actualización regulatoria positiva tras una reunión del 6 de octubre de 2025 con el relator de la EMA (MEB). El relator indicó que la supervivencia global (OS) con resultados finales de dos años, estadísticamente significativos, podría servir como endpoint primario para una autorización de comercialización condicionada (CMA). El relator consideró que los datos de seguridad, no clínicos y de CMC son suficientes para respaldar una presentación CMA. La reunión avanza la asesoría científica formal de la EMA esperada en diciembre de 2025 y estableció una vía para un programa aleatorizado de confirmación y una posible expansión de la etiqueta. La MHRA del Reino Unido concedió una reunión expedita de Market Access Scientific Advice para apoyar el proceso de MAA.
OS Therapies (NYSE: OSTX)가 EMA 보고관(MEB)과의 2025년 10월 6일 회의 후 긍정적인 규제 업데이트를 발표했습니다. 보고관은 전체 생존(OS)이 통계적으로 유의미한 최종 2년 결과를 가진 경우 CMA의 주요 평가변수로 사용될 수 있다고 시사했습니다. 보고관은 CMA 제출을 뒷받침하기에 안전성, 비임상 및 CMC 데이터가 충분하다고 보았습니다. 이 회의는 2025년 12월에 예정된 EMA 과학 자문(Scientific Advice) 공식화를 앞당겼고, 확인적 무작위 프로그램 및 라벨 확장의 가능성에 대한 경로를 확립했습니다. 영국 MHRA는 MAA 절차를 지원하기 위해 신속한 Market Access Scientific Advice 회의를 승인했습니다.
OS Therapies (NYSE: OSTX) a publié une mise à jour réglementaire positive après une réunion du 6 octobre 2025 avec le rapporteur de l'EMA (MEB). Le rapporteur a indiqué que la survie globale (OS) avec des résultats finaux sur deux ans, statistiquement significatifs, pourrait servir d'objectif principal pour une autorisation de mise sur le marché conditionnelle (CMA). Le rapporteur a estimé que les données de sécurité, non cliniques et CMC étaient suffisantes pour soutenir une soumission CMA. La réunion fait progresser l'avis scientifique formel de l'EMA prévu en décembre 2025 et a établi une voie pour un programme randomisé de confirmation et une possible expansion de l'étiquette. Le MHRA du Royaume-Uni a accordé une réunion accélérée de Market Access Scientific Advice pour soutenir le processus de MAA.
OS Therapies (NYSE: OSTX) berichtete nach einem positiven regulatorischen Update nach einem Treffen am 6. Oktober 2025 mit dem EMA-Berichterstatter (MEB). Der Berichterstatter gab an, dass das Gesamtüberleben (OS) mit statistisch signifikanten, finalen Zwei-Jahres-Ergebnissen als primärer Endpunkt für eine bedingte Marktzulassung (CMA) dienen könnte. Der Berichterstatter betrachtete Sicherheits-, Nicht-klinische- und CMC-Daten als ausreichend, um eine CMA-Einreichung zu unterstützen. Das Treffen beschleunigt die formelle EMA-Wissenschaftliche Beratung, die voraussichtlich im Dezember 2025 stattfinden wird, und schuf einen Weg für ein bestätigendes randomisiertes Programm sowie eine mögliche Etikettenexpansion. Die britische MHRA hat ein beschleunigtes Market Access Scientific Advice-Treffen genehmigt, um den MAA-Prozess zu unterstützen.
OS Therapies (NYSE: OSTX) أصدرت تحديثاً تنظيمياً إيجابياً بعد اجتماع في 6 أكتوبر 2025 مع مقرر EMA (MEB). أشارت المقررة إلى أن الإحياء العام (OS) مع نتائج نهائية ذات دلالات إحصائية لمدة عامين قد تكون هدفاً رئيسياً لـ تصريح تسويق مشروط (CMA). رأى المقررة أن بيانات السلامة والبيانات غير السريرية وبيانات CMC كافية لدعم تقديم CMA. يعزز الاجتماع المشورة العلمية الرسمية لـ EMA المتوقع عقدها في ديسمبر 2025 ووضع مسار لبرنامج عشوائي تأكيدي وإمكانية توسيع التسمية. منحت MHRA في المملكة المتحدة اجتماعاً سريعاً للنصح العلمي للوصول إلى السوق لدعم عملية MAA).
OS Therapies (NYSE: OSTX) 在与 EMA 报告官（MEB）于 2025 年 10 月 6 日会晤后宣布积极的监管更新。报告官表示，具统计学显著性的、两年最终结果的总体生存率（OS）可能成为有条件上市许可（CMA）的主要终点。报告官认为安全性、非临床和 CMC 数据足以支持 CMA 申请。此次会晤推动了预计于 2025 年 12 月进行的 EMA 科学咨询（Scientific Advice）正式化，并为确认性随机项目以及潜在的标签扩展建立了路径。英国 MHRA 授予了一次加速的市场准入科学咨询会议，以支持 MAA 流程。
- Rapporteur supports OS as potential primary endpoint for CMA
- Safety profile from Fully Resected Osteosarcoma study confirmed positive
- Non-clinical data deemed sufficient to support CMA submission
- CMC package viewed as sufficient to support CMA
- EMA Scientific Advice anticipated in December 2025
- UK MHRA granted expedited Market Access Scientific Advice meeting
- 12-month EFS considered potentially inappropriate as primary endpoint
- A confirmatory randomized trial is required to secure full marketing authorization
Insights
EMA rapporteur supports overall survival as a primary endpoint and a pathway toward conditional marketing authorization.
Alignment with the Dutch MEB on safety, non‑clinical, and CMC matters creates a clear regulatory bridge for OST‑HER2. The rapporteur indicated statistically significant, final two‑year overall survival data could serve as a primary endpoint for a conditional marketing authorization, and data from over 500 patients treated with related Listeria candidates may supplement the submission.
Key dependencies remain defined and factual: confirmatory biomarker analyses referenced could strengthen the OS signal, and the planned EMA Scientific Advice in
Watch for the formal EMA Scientific Advice outcome around
Overall survival recognized as key efficacy endpoint in osteosarcoma, where no standard of care exists
Rapporteur highlights potential broader benefits of OST-HER2 in pulmonary and primary osteosarcoma settings, supported by translational canine data from the University of Pennsylvania
New York, New York--(Newsfile Corp. - October 9, 2025) - OS Therapies Inc. (NYSE American: OSTX) ("OS Therapies" or "the Company"), a clinical-stage cancer immunotherapy and antibody drug conjugate biotechnology company, today announced a positive regulatory update following an October 6, 2025 meeting with its European Medicines Agency (EMA) rapporteur, the Dutch Medicines Evaluation Board (MEB).
During the meeting, OS Therapies and the Dutch Rapporteur aligned on key areas, including safety, non-clinical and chemistry, manufacturing, and controls (CMC) data in support of the Company's ongoing OST-HER2 Phase 2b clinical trial in the prevention or delay of recurrent, fully-resected, pulmonary metastatic osteosarcoma. The Rapporteur advised that the overall survival results, demonstrating statistically significant, final two-year data, may serve as an appropriate primary endpoint for consideration of conditional marketing authorization (CMA).
The meeting represented an important milestone toward formal EMA Scientific Advice, anticipated in December 2025. A potential pathway was also established to support a confirmatory, randomized clinical development program, which could explore additional osteosarcoma settings and potentially expand the product label upon full marketing authorization.
Meeting outcomes
- The safety profile from the Fully Resected Osteosarcoma clinical study was confirmed as positive. In addition, data from other Listeria monocytogenes candidates, representing more than 500 patients treated across four other therapeutic indications, may be sufficient to support a conditional marketing authorization (CMA).
- Non-clinical data is sufficient to support a CMA submission.
- The chemistry, manufacturing, and controls (CMC) data package was also viewed as sufficient to support a CMA.
- Efficacy data available as of July 2025 from the Fully Resected Osteosarcoma Trial were viewed as encouraging. The Rapporteur noted that 12-month Event-Free Survival (EFS) may not be the most appropriate endpoint and that overall survival (OS) could provide a stronger measure of clinical benefit, particularly if ongoing biomarker analyses confirm differential immune activation among patients showing favorable outcomes.
- The Rapporteur also indicated that efficacy data generated outside the Fully Resected Osteosarcoma Trial, such as in recurrent, unresectable, pulmonary metastatic osteosarcoma setting, could be incorporated into a post-market confirmatory clinical development program.
Additionally, the company is pleased to report that following the recently announced commencement of the Marketing Authorisation Application (MAA) submissions process with the UK MHRA, that the Agency has kindly granted OS Therapies an expedited Market Access Scientific Advice Meeting. This is an important milestone in the MAA submission and approval process. The meeting is intended to ensure alignment between Sponsors and the Agency on issues that will be evaluated during the MAA review process, with the intent of accelerating patient access.
"We are pleased that the Dutch Rapporteur's evaluation of the data submitted aligns closely with UK MHRA and US FDA so far on safety, non-clinical and CMC," said Paul Romness, MPH, Chairman & CEO of OS Therapies. "Importantly the feedback on clinical efficacy provides a clear regulatory pathway. We believe this will enable us to pursue a conditional marketing authorization while advancing a confirmatory, global randomized clinical study in parallel. This next trial may evaluate OST-HER2 in one or more osteosarcoma clinical settings that could determine the full breadth of OST-HER2 clinical utility, given its immunotherapy mechanism of action in light of the exciting data generated in highly translational canine studies generated at the University of Pennsylvania."
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. 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 2025 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
Jessica Starman, MBA
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/269769
FAQ
What did OS Therapies (OSTX) learn from the October 6, 2025 EMA rapporteur meeting?
How does the rapporteur's view on endpoints affect OSTX's OST-HER2 Phase 2b trial?
What are the next regulatory milestones for OS Therapies (OSTX)?
Will OSTX need additional trials after a conditional approval?
Did the rapporteur raise safety or CMC concerns for OSTX's OST-HER2 program?
