OS Therapies Incorporated (NYSE American: OSTX) is a clinical-stage oncology and biopharmaceutical company focused on osteosarcoma and other solid tumors. News about OS Therapies centers on its listeria-based cancer immunotherapy programs, regulatory interactions, capital markets activity, and the planned spin-off of its veterinary oncology subsidiary, OS Animal Health.
A major theme in OSTX news flow is the progress of OST-HER2 (daznelene lisbac), the company’s lead listeria-based immunotherapy targeting the HER2 protein. Press releases highlight positive Phase 2b data in recurrent, fully resected, pulmonary metastatic osteosarcoma, including statistically significant benefit in 12-month event free survival and reported 2-year overall survival outcomes. The company also reports immune biomarker analyses from its human metastatic osteosarcoma trial and related canine osteosarcoma studies, emphasizing the role of Comparative Oncology and interferon gamma pathway biomarkers as potential surrogate markers of clinical efficacy.
Investors following OSTX news will see regular updates on regulatory milestones, such as FDA Type C and other meetings, waiver of the BLA application fee for OST-HER2, EMA Union Marketing Authorisation eligibility, and preparations for Biologics License Application and Marketing Authorisation Application submissions in the United States, United Kingdom, and European Union. Company outlook releases describe anticipated timelines for regulatory submissions, potential conditional approvals, and planned interactions with FDA, MHRA, and EMA.
OS Therapies also issues news on capital raising and corporate transactions, including warrant exercise inducement agreements, gross proceeds from warrant exercises, and the intended use of proceeds to fund OST-HER2 regulatory and commercial preparation activities and the proposed OS Animal Health spin-off. Additional news items cover the veterinary oncology strategy for canine osteosarcoma, recognition of OST-HER2 in documentaries and awards, and the development of the company’s tunable ADC (tADC) platform.
For readers tracking OSTX, this news feed provides a consolidated view of clinical trial updates, biomarker findings, regulatory developments, financing events, and the evolution of both the human and animal health franchises. Regular visits can help investors and observers monitor how OS Therapies advances OST-HER2 and its broader oncology pipeline through key clinical and regulatory inflection points.
OS Therapies (OSTX) announced that its animal health subsidiary received USDA feedback on the regulatory pathway for OST-HER2 in canine osteosarcoma. The wholly owned subsidiary, OS Animal Health (OSAH), received guidance on clinical efficacy, safety, non-clinical requirements and manufacturing controls ahead of an upcoming conditional licensure request. OSAH intends to seek a new conditional license using existing clinical efficacy data covering prevention of metastasis, metastatic disease control and prevention of amputation in frontline osteosarcoma.
OSAH expects additional clinical studies will be needed for full USDA licensure and hopes to launch the product commercially in the United States in 2027. OS Therapies is evaluating alternatives to monetize OSAH. The subsidiary plans crowdfunding in the fourth quarter of 2026 to expand its shareholder base to meet initial listing standards for a U.S. national stock exchange.
OS Therapies (OSTX) reported final three-year overall survival of 72.7% in its Phase 2b trial of OST-HER2 for pulmonary metastatic osteosarcoma.
Survival was 45.8% in a comparable combined published historical control group, with p = 0.0006 indicating statistical significance. The trial enrolled 41 patients with fully resected pulmonary metastatic osteosarcoma; four patients were lost to follow-up. The study evaluated prevention or delay of recurrence.
The company intends to complete U.S. accelerated approval and U.K., European and Australian conditional marketing authorization submissions in fourth-quarter 2026. It reports alignment across international regulators on the confirmatory Phase 3 trial design and is preparing a U.K. clinical trial authorization submission. Starting Phase 3 is a prerequisite for those approvals. WHO accepted Herlystic as OST-HER2's proprietary brand name.
OS Therapies (OSTX) appointed Kerry Clem as Chief Commercial Officer and Frank Knuettel II as Chief Financial Officer to support commercialization preparations. Clem leads U.S., U.K. and European launch planning for Herlystic, an investigational immunotherapy intended to prevent or delay recurrence in fully resected, pulmonary metastatic osteosarcoma. The company plans an initial U.S. launch subject to regulatory approval, targets a U.K. application early in the fourth quarter of 2026, and also plans U.S. and European applications.
Its U.K. subsidiary completed implementation of a refundable research tax credit strategy. OS Therapies has received over $3 million in VAT refunds and accrued over $7 million in research tax credits. Returned funds are earmarked primarily for Herlystic manufacturing and confirmatory Phase 3 development. Agreements with its largest vendors defer most outstanding accounts payable until the second quarter of 2027.
OS Therapies (OSTX) received World Health Organization approval for Herlystic as the brand name for OST-HER2 on September 24, 2026. The WHO had previously approved daznelimgene lisbac as its nonproprietary name. The naming decision is not an authorization to market the therapy.
OS Therapies plans to seek early market access for OST-HER2 in metastatic osteosarcoma, starting with a U.K. conditional marketing application in the fourth quarter of 2026. The U.K. regulator is taking the lead under Project Orbis, a framework for coordinated international review of oncology products. The company plans subsequent submissions in the U.S., Europe and Australia after final three-year overall survival data becomes available. Its U.S. biologics license application submission began in January 2026. The company's Phase 2b trial assessed 12-month event-free survival as its primary endpoint and overall survival as a secondary endpoint.
OS Therapies (OSTX) has aligned global regulators and updated development plans for OST‑HER2 in metastatic osteosarcoma under Project Orbis as of September 21, 2026.
Following a U.K. MHRA Scientific Advice Meeting, MHRA agreed to initiate and lead a confirmatory Phase 3 trial in the U.K. using requalified Phase 2b drug product, with trial start expected in mid‑Q4 2026 and a Conditional Marketing Authorisation Application submission in the coming weeks. MHRA is taking the global regulatory lead with FDA and EMA and has granted access to the U.K. Clinical Practice Research Datalink registry to strengthen comparator data during early market access.
FDA has aligned with the adaptive Phase 3 design in a Type C Statistical Methods Meeting. A rolling BLA filing for OST‑HER2 in osteosarcoma, initiated in Q1 2026, is targeted for completion in Q4 2026 as the company awaits FDA decisions on RMAT, Rolling Review and CNPV requests. Commercial/Phase 3‑ready OST‑HER2 product is expected in 2027 to support trial expansion and launches in Project Orbis countries. OST‑HER2 holds multiple ODD, FTD, RPDD and ATMP designations, and a future U.S. BLA could yield a Priority Review Voucher, with a recent comparable PRV sale disclosed at $220 million.
OS Therapies (OSTX) reached additional alignment with the U.S. FDA on the adaptive design for its planned Phase 3 trial of OST-HER2 in fully resected, pulmonary metastatic osteosarcoma, with trial initiation expected in the fourth quarter of 2026.
The company also accepted a request from the U.K. MHRA to act as its representative into FDA’s Project Orbis, enabling harmonized oncology review with FDA and EMA after a recent successful Statistical Methods Scientific Advice Meeting. OS Therapies plans an invited Type B Pre-BLA meeting with FDA in the fourth quarter of 2026, following submission of the clinical section including 3-year overall survival data, to complete a BLA filing that began in January 2026. The company is pursuing U.S. accelerated approval and conditional marketing authorizations in Europe, the U.K. and Australia for OST-HER2 in metastatic osteosarcoma and holds ODD, FTD and RPDD from FDA and ODD, FTD and ATMP from EMA, with potential Priority Review Voucher eligibility if the BLA is approved.
OS Therapies (OSTX) has obtained full alignment with the U.K. MHRA and the EU EMA on its planned Conditional Marketing Authorisation Applications (CMAAs) for OST-HER2 as of September 15, 2026.
MHRA agreed that the company’s overall survival historical-control data, derived from a systematic review of peer‑reviewed literature by independent biostatistics advisors, are appropriate for use in the orphan indication of preventing or delaying recurrence in fully resected, pulmonary metastatic osteosarcoma. Regulators also aligned on the design of the required confirmatory Phase 3 trial, including the proportion of patients to receive remaining Phase 2 drug product versus new Phase 3 material. OS Therapies expects to complete its CMAA submissions in the coming weeks, intends to start the confirmatory Phase 3 trial in the fourth quarter of 2026, and is pursuing a U.S. BLA under the Accelerated Approval Program with potential rolling review.
OS Therapies (OSTX) reported an interim 3-year overall survival rate of 71.2% for OST-HER2-treated patients in its Phase 2b pulmonary metastatic osteosarcoma trial, versus 45.8% in a comparable combined historical control group (p = 0.002).
The analysis covers 41 enrolled patients, with two not yet at the 3-year timepoint and six lost to follow-up. The company said these data support ongoing regulatory interactions aimed at early market access, including a planned Biologics License Application (BLA) under the FDA’s Accelerated Approval Program and Conditional Marketing Authorization Applications (CMAAs) in the U.K., Europe and Australia in the fourth quarter of 2026, targeting commercial availability in 2027.
OS Therapies also received $3.15 million in VAT refunds into its U.K. subsidiary and expects at least an additional $7.2 million in refundable VAT and R&D tax credits, which are earmarked to fund initiation of a confirmatory Phase 3 trial in the U.K. OST-HER2 has ODD, FTD and RPDD in the U.S. and ODD, FTD and ATMP in Europe, and a rolling BLA submission that began in January 2026.
OS Therapies (OSTX) announced upcoming conference participation and a detailed regulatory roadmap for its OST-HER2 metastatic osteosarcoma program as of September 2026.
The company expects FDA and MHRA statistical methods meetings in September 2026, with minutes in October and additional regulatory meetings through Q4 2026. It plans to seek a Biologics License Application (BLA) under the FDA Accelerated Approval Program and Conditional Marketing Authorization Applications (CMAAs) in the U.K., Europe and Australia in Q4 2026. OST-HER2 has FDA ODD, FTD and RPDD and EMA ODD, FTD and ATMP designations, and prior Phase 2b data showed clinically meaningful benefit in 12‑month event‑free survival and overall survival. If a U.S. BLA is granted, the company would be eligible for a tradeable Priority Review Voucher; a recent comparable voucher sale reached $220 million, though OS Therapies cautions that future values are uncertain.
OS Therapies (NYSE American: OSTX) reported second quarter 2026 results and regulatory progress for lead immunotherapy OST-HER2 in metastatic osteosarcoma. The company arranged up to $10 million in debt financing backed by U.K. VAT refunds and reimbursable R&D tax credits, with $5 million funded at the August 10, 2026 first closing.
According to OS Therapies, OST U.K. had over $3 million VAT refunds receivable at June 30, 2026 and expects about $1 million additional VAT refunds plus at least $4.2 million refundable R&D tax credits by Q3-end, supporting a projected financial runway into 2027.
Clinically, 2.5‑year overall survival in the Metastatic Osteosarcoma Program was 75% vs. 47% (p = 0.003), with no new deaths between 2‑year and 2.5‑year timepoints in the OST‑HER2 group. Regulators including FDA, EMA, MHRA and TGA have aligned on 3‑year overall survival and biomarker endpoints and Phase 3 design. Q2 2026 net operating loss was $8.576 million versus $4.839 million a year earlier; net loss per share was $0.20 on 43.904 million weighted average shares.