OS Therapies Requests Meeting with FDA to Gain Agreement on Surrogate Endpoint(s) for Breakthrough Therapy Designation & Accelerated Approval of OST-HER2 in the Prevention of Recurrence of Fully Resected, Lung Metastatic Osteosarcoma
OS Therapies (NYSE-A: OSTX) has submitted a request for a formal meeting with the FDA's CBER to discuss endpoints for Breakthrough Therapy Designation and Accelerated Approval of OST-HER2, their immunotherapy candidate for preventing recurrence in fully resected, lung metastatic osteosarcoma.
The company reported positive Phase 2b clinical trial results from a 21-site study of 39 patients, showing statistically significant improvement in 12-month event-free survival compared to historical control (33% vs. 20%, p=0.0158). Following FDA feedback, OS Therapies designed OST-400, a retrospective study collecting over 200 patient records from US, UK, and French oncology centers.
The FDA meeting is expected in Q2 2025, with potential Accelerated Approval by year-end 2025. OST-HER2 has received Rare Pediatric Disease Designation, making it eligible for a Priority Review Voucher if approved before September 30, 2026. The company has sufficient cash to operate into mid-2026.
OS Therapies (NYSE-A: OSTX) ha presentato una richiesta per un incontro formale con il CBER della FDA per discutere gli obiettivi per la Designazione di Terapia Innovativa e l'Approvazione Accelerata di OST-HER2, il loro candidato immunoterapico per prevenire le recidive nell'osteosarcoma metastatico polmonare completamente asportato.
L'azienda ha riportato risultati positivi della sperimentazione clinica di Fase 2b da uno studio condotto in 21 centri su 39 pazienti, mostrando un miglioramento statisticamente significativo nella sopravvivenza libera da eventi a 12 mesi rispetto al controllo storico (33% vs. 20%, p=0.0158). A seguito del feedback della FDA, OS Therapies ha progettato OST-400, uno studio retrospettivo che raccoglie oltre 200 cartelle cliniche da centri oncologici negli Stati Uniti, Regno Unito e Francia.
Si prevede che l'incontro con la FDA avvenga nel secondo trimestre del 2025, con una possibile Approvazione Accelerata entro la fine del 2025. OST-HER2 ha ricevuto la Designazione di Malattia Pediatrica Rara, rendendolo idoneo per un Voucher di Revisione Prioritaria se approvato prima del 30 settembre 2026. L'azienda ha liquidità sufficiente per operare fino a metà 2026.
OS Therapies (NYSE-A: OSTX) ha presentado una solicitud para una reunión formal con el CBER de la FDA para discutir los objetivos de la Designación de Terapia Innovadora y la Aprobación Acelerada de OST-HER2, su candidato de inmunoterapia para prevenir la recurrencia en osteosarcoma metastásico pulmonar completamente resecado.
La compañía informó sobre resultados positivos del ensayo clínico de Fase 2b de un estudio realizado en 21 sitios con 39 pacientes, mostrando una mejora estadísticamente significativa en la supervivencia libre de eventos a 12 meses en comparación con el control histórico (33% vs. 20%, p=0.0158). Tras la retroalimentación de la FDA, OS Therapies diseñó OST-400, un estudio retrospectivo que recopila más de 200 registros de pacientes de centros oncológicos en EE. UU., Reino Unido y Francia.
Se espera que la reunión con la FDA tenga lugar en el segundo trimestre de 2025, con una posible Aprobación Acelerada para fines de 2025. OST-HER2 ha recibido la Designación de Enfermedad Pediátrica Rara, lo que lo hace elegible para un Voucher de Revisión Prioritaria si se aprueba antes del 30 de septiembre de 2026. La compañía tiene suficiente efectivo para operar hasta mediados de 2026.
OS Therapies (NYSE-A: OSTX)는 FDA의 CBER와의 공식 회의 요청서를 제출하여 OST-HER2의 혁신 치료 지정 및 가속 승인에 대한 목표를 논의하고 있습니다. OST-HER2는 완전히 절제된 폐 전이 골육종의 재발을 방지하기 위한 면역 요법 후보입니다.
회사는 39명의 환자를 대상으로 한 21개 사이트 연구에서 긍정적인 2b상 임상 시험 결과를 보고하였으며, 역사적 대조군에 비해 12개월 사건 자유 생존율에서 통계적으로 유의미한 개선을 보여주었습니다 (33% 대 20%, p=0.0158). FDA의 피드백에 따라 OS Therapies는 미국, 영국 및 프랑스의 종양학 센터에서 200건 이상의 환자 기록을 수집하는 회고적 연구인 OST-400을 설계했습니다.
FDA 회의는 2025년 2분기에 예정되어 있으며, 2025년 연말까지 가속 승인이 가능할 것으로 보입니다. OST-HER2는 희귀 소아 질환 지정받아 2026년 9월 30일 이전에 승인될 경우 우선 검토 바우처를 받을 수 있습니다. 회사는 2026년 중반까지 운영할 수 있는 충분한 자금을 보유하고 있습니다.
OS Therapies (NYSE-A: OSTX) a soumis une demande de réunion formelle avec le CBER de la FDA pour discuter des objectifs de désignation de thérapie innovante et d'approbation accélérée pour OST-HER2, leur candidat immunothérapeutique destiné à prévenir la récidive dans l'ostéosarcome pulmonaire métastatique complètement réséqué.
La société a rapporté des résultats positifs d'un essai clinique de phase 2b d'une étude menée dans 21 sites avec 39 patients, montrant une amélioration statistiquement significative de la survie sans événement à 12 mois par rapport au contrôle historique (33 % contre 20 %, p=0.0158). Suite aux retours de la FDA, OS Therapies a conçu OST-400, une étude rétrospective recueillant plus de 200 dossiers de patients provenant de centres oncologiques aux États-Unis, au Royaume-Uni et en France.
La réunion avec la FDA est prévue pour le deuxième trimestre de 2025, avec une approbation accélérée potentielle d'ici la fin de 2025. OST-HER2 a reçu la désignation de maladie pédiatrique rare, ce qui le rend éligible à un bon de révision prioritaire s'il est approuvé avant le 30 septembre 2026. La société dispose de suffisamment de liquidités pour fonctionner jusqu'à mi-2026.
OS Therapies (NYSE-A: OSTX) hat einen Antrag auf ein formelles Treffen mit dem CBER der FDA eingereicht, um die Endpunkte für die Designation als Durchbruchtherapie und die beschleunigte Genehmigung von OST-HER2, ihrem Immuntherapie-Kandidaten zur Verhinderung von Rückfällen bei vollständig reseziertem, lungemetastasiertem Osteosarkom, zu besprechen.
Das Unternehmen berichtete von positiven Ergebnissen der Phase 2b klinischen Studie aus einer Studie an 21 Standorten mit 39 Patienten, die eine statistisch signifikante Verbesserung der 12-monatigen ereignisfreien Überlebensrate im Vergleich zur historischen Kontrolle zeigten (33 % vs. 20 %, p=0.0158). Nach dem Feedback der FDA entwarf OS Therapies OST-400, eine retrospektive Studie, die über 200 Patientenakten aus US-, UK- und französischen Onkologien sammelt.
Das Treffen mit der FDA wird im 2. Quartal 2025 erwartet, mit einer möglichen beschleunigten Genehmigung bis Ende 2025. OST-HER2 hat die Designation als seltene pädiatrische Erkrankung erhalten, was es berechtigt, einen Prioritätsprüfungs-Gutschein zu erhalten, wenn es vor dem 30. September 2026 genehmigt wird. Das Unternehmen hat genügend Bargeld, um bis Mitte 2026 zu operieren.
- Positive Phase 2b results showing 33% vs 20% improvement in 12-month event-free survival
- Potential Accelerated Approval by end of 2025
- Eligible for Priority Review Voucher worth potentially $150 million if approved before Sept 2026
- Sufficient cash runway into mid-2026
- Small Phase 2b trial size of only 39 patients
- Relies on historical control data rather than placebo-controlled trial
- FDA approval timeline depends on successful regulatory meetings and data acceptance
Insights
OS Therapies' FDA meeting request represents a significant regulatory milestone for OST-HER2. Following FDA's April 2nd suggestion, this meeting aims to secure agreement on surrogate endpoints for both Breakthrough Therapy Designation and Accelerated Approval - potentially enabling a rolling BLA submission with approval targeted by year-end 2025.
The company's dual-track strategy addresses FDA's previous BTD request feedback through their OST-400 retrospective study, which has identified over 200 matched patient records from leading oncology centers to establish an external historic control. This approach is particularly relevant for rare pediatric cancers where placebo-controlled trials raise ethical concerns.
Most compelling is the Rare Pediatric Disease Designation (RPDD) already secured for OST-HER2. If conditional approval comes before September 2026, OS Therapies would receive a Priority Review Voucher - potentially worth
The regulatory pathway leverages FDA's increasing openness to external control groups for ultra-rare conditions. Their sufficient cash runway into mid-2026 provides adequate operational stability through these regulatory milestones. The scheduled data presentation in June followed by rolling BLA submission creates multiple potential near-term catalysts.
The Phase 2b clinical data for OST-HER2 shows promising efficacy in a devastating condition with few effective options. The
OST-HER2's immunotherapy approach - using bioengineered Listeria monocytogenes to target HER2-expressing cancer cells - represents an innovative mechanistic strategy. While the single-arm trial design with 39 patients might raise questions in common cancers, this approach is appropriate for rare pediatric conditions where recruitment challenges exist.
The prevention of recurrence in fully resected, lung metastatic osteosarcoma addresses a critical unmet need. Current standard treatments after resection have disappointing outcomes, with recurrence rates remaining stubbornly high. A therapy that extends event-free survival in this setting would be tremendously valuable.
Their comparative oncology approach - studying similar cancers in dogs and humans - speaks to the innovative translational medicine strategy being employed. The upcoming data presentation at MIB Factor in June will be crucial for understanding the durability of response and further efficacy signals from their clinical program.
- OS Therapies applies for meeting per FDA suggestion received on April 2, 2025
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Based on prior FDA guidance, greater than 200 suitable matched lung metastatic osteosarcoma patient records identified from leading oncology centers in the US,
UK andFrance for inclusion in OST-400, a Retrospective Longitudinal Study of Recurrent Osteosarcoma after Resection in Children and Young Adults
“We are excited to meet with the FDA – and commence market access discussions - the goal of receiving Accelerated Approval for a Biologics License Application of OST-HER2 in the prevention or delay of recurrence lung metastatic osteosarcoma by year-end 2025,” said Dr. Robert Petit, Chief Medical & Scientific Officer of OS Therapies. “We believe that we have identified the comparator data necessary to address the comments from FDA regarding our prior BTD request. We expect this data will also be able support our application for Accelerated Approval. Our clinical and regulatory teams are diligently preparing for the meeting and the subsequent BLA submission that is targeted to begin after the public release of additional clinical trial data at MIB Factor in June.”
OST-HER2 has received Rare Pediatric Disease Designation (RPDD) for osteosarcoma from the US FDA, and if it receives a conditional BLA via Accelerated Review prior to September 30, 2026, it will become eligible to receive a Priority Review Voucher (PRV) that it intends to immediately sell. The most recent PRV sale, valued at
“We congratulate the new Acting Director at CBER, Dr. Scott Steele, who comes from a translational medicine background and understands the importance of Comparative Oncology in the development of new cancer immunotherapies and note that President Trump cited deadly rare pediatric cancers as a priority for continued product development for the administration,” said Paul Romness, CEO of OS Therapies. “We believe OST-HER2 will make a significant difference in the treatment of osteosarcoma and welcome the opportunity to engage with FDA to get this investigational treatment to patients as quickly as possible.”
The Company announced positive Phase 2b clinical trial results from its US-based, 21 site, single-arm, open-label clinical study of 39 patients in recurrent, fully resected, lung metastatic osteosarcoma that demonstrated a statistically significant improvement in the proportion of patients that achieved the primary endpoint of 12-month event free survival (EFS) when compared with historical control (
Following feedback from FDA, the Company designed OST-400, a Retrospective Longitudinal Study of Recurrent Osteosarcoma after Resection in Children and Young Adults being conducted with clinicians from leading oncology centers in
The Company intends to present the data from the Phase 2b clinical trial of OST-HER2 compared with the matched, external, historic control comparator agreed upon with FDA derived from OST-400 at MIB Factor in June 2025. Thereafter, the Company intends to file a BLA for OST-HER2 in the prevention or delay of recurrence of fully resected, lung metastatic osteosarcoma, with the aim of receiving approval by the end of 2025.
OST-HER2, an immunotherapy for osteosarcoma using a HER2 bioengineered form of the bacteria Listeria monocytogenes to trigger a strong immune response against cancer cells expressing HER2, is being featured in the upcoming movie Shelter Me: The Cancer Pioneers. The movie offers a look into canine comparative oncology, a field that compares treatment of cancers in dogs to those in people and covers developing treatments for rare forms of cancer. A trailer for the movie is available here. The movie will be aired live nationally on PBS and will available via streaming on PBS’ website in early May 2025.
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 US Food & Drug Administration and Fast-Track and Orphan Drug designations from the US FDA and European Medicines Agency. The Company 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 US 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
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 news 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 US FDA and grant of a priority review voucher and other risks and uncertainties described in “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in the Company’s registration statement on Form S-1 filed with the Securities and Exchange Commission (the “SEC”) on November 12, 2024, as amended on November 27, 2024, and other subsequent documents we file with the SEC, including but not limited to our Quarterly Reports on Form 10-Q. 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.
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OS Therapies Contact Information:
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Source: OS Therapies
FAQ
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