OS Therapies Initiates US FDA BLA Filing for OST-HER2 in the Prevention or Delay of Recurrent, Fully Resected, Pulmonary Metastatic Osteosarcoma

Rhea-AI Summary

OS Therapies (NYSE: OSTX) has initiated a U.S. Biologics License Application (BLA) submission for OST-HER2 to prevent or delay recurrent, fully resected pulmonary metastatic osteosarcoma.

The company submitted Non‑Clinical and CMC modules and requested a Rolling Review. A Type D meeting is expected in March 2026 to review comparative oncology biomarker data, with the clinical BLA module targeted for submission by end of March 2026 and potential approval by September 30, 2026, which would preserve eligibility for a Priority Review Voucher under Rare Pediatric Disease Designation.

Positive

• Non‑Clinical and CMC BLA modules submitted to FDA
• Request for Rolling Review submitted on January 30, 2026
• Type D meeting requested for March 2026 to review biomarker data
• Clinical BLA module expected by end of March 2026
• Updated RMAT designation requests submitted with recent biomarker data
• Eligibility to receive Priority Review Voucher if approved by 09/30/2026

Negative

• Clinical BLA module not yet submitted; pending Type D meeting review
• Regulatory approval timeline contingent on FDA review of comparative oncology data
• Approval by 09/30/2026 required to secure Priority Review Voucher

News Market Reaction

+2.21%

2 alerts

+2.21% News Effect

+10.2% Peak Tracked

+$1M Valuation Impact

$49M Market Cap

0.0x Rel. Volume

On the day this news was published, OSTX gained 2.21%, reflecting a moderate positive market reaction. Argus tracked a peak move of +10.2% during that session. Our momentum scanner triggered 2 alerts that day, indicating moderate trading interest and price volatility. This price movement added approximately $1M to the company's valuation, bringing the market cap to $49M at that time.

Data tracked by StockTitan Argus on the day of publication.

Key Figures

Rolling Review request date: January 30, 2026 Type D Meeting timing: March 2026 Final clinical module: End of March 2026 +2 more

5 metrics

Rolling Review request date January 30, 2026 FDA Rolling Review request for OST-HER2 BLA

Type D Meeting timing March 2026 Expected FDA Type D Meeting on Comparative Oncology biomarker data

Final clinical module End of March 2026 Expected submission of clinical BLA module to FDA

Target approval timing September 30, 2026 Company’s anticipated latest approval date for OST-HER2 BLA

Recent PRV sale $200 million Most recent Priority Review Voucher sale in January 2026

Market Reality Check

Price: $1.36 Vol: Volume 414,303 is below t...

low vol

$1.36 Last Close

Volume Volume 414,303 is below the 20-day average of 703,036, suggesting a muted pre-news setup. low

Technical Shares at $1.36 are trading below the 200-day MA of $1.81 and about 54.36% under the 52-week high.

Peers on Argus

Two tracked biotech peers, including ANL, were in downside momentum (median move...

2 Down

Two tracked biotech peers, including ANL, were in downside momentum (median move -14.8%), indicating broader sector pressure alongside OSTX’s pre-news softness.

Historical Context

5 past events · Latest: Jan 15 (Positive)

Pattern 5 events

Date	Event	Sentiment	Move	Catalyst
Jan 15	Clinical biomarker update	Positive	-5.8%	Positive Phase 2b OST-HER2 biomarker-survival correlation in metastatic osteosarcoma.
Jan 14	Subsidiary IPO plan	Positive	+0.7%	Planned OS Animal Health IPO and prospective share distribution to OSTX holders.
Jan 12	Warrant financing	Neutral	-7.1%	Warrant inducement raising $7.53M gross proceeds and extending cash runway.
Jan 05	Corporate outlook	Positive	+7.5%	H1 2026 regulatory roadmap with BLA and EMA/MHRA filing timelines for OST-HER2.
Dec 15	FDA Type C meeting	Positive	-7.7%	FDA signaled single-arm data could support Accelerated Approval BLA pathway.

Pattern Detected

Recent OST-HER2 regulatory and clinical updates have often been followed by weak or negative price reactions, even when the news itself was constructive.

Recent Company History

Over the last few months, OS Therapies has steadily advanced OST-HER2 toward registration. A successful FDA Type C meeting on Dec 15, 2025 confirmed that single-arm data could support a BLA via Accelerated Approval, yet shares fell. Subsequent corporate outlook and financing updates in January 2026 outlined clear timelines, fresh capital of $7.53M, and positive Phase 2b biomarker data, but price reactions were mixed to negative. Today’s BLA-initiating announcement continues that regulatory progression toward targeted 2026 approvals.

Regulatory & Risk Context

Active S-3 Shelf · $100,000,000

Shelf Active

Active S-3 Shelf Registration 2025-08-08

$100,000,000 registered capacity

The company has an active S-3 shelf filed on 2025-08-08 to offer up to $100,000,000 of securities, plus an at-the-market program of up to $18,000,000 in common stock. The shelf is not yet effective, but two 424B supplements were filed in 2025, indicating prior usage activity and ongoing capacity for future capital raises tied to clinical and regulatory milestones.

Market Pulse Summary

This announcement formalizes a key step toward U.S. approval, with OST-HER2’s BLA now in process und...

Analysis

This announcement formalizes a key step toward U.S. approval, with OST-HER2’s BLA now in process under a Rolling Review and a clinical module expected by the end of March 2026. It builds on prior FDA interactions that outlined an Accelerated Approval path and ties directly to biomarker data disclosed in January 2026. Investors may focus on execution of the Type D Meeting, timing toward the September 30, 2026 approval goal, and how any future capital raises under the existing shelf intersect with this path.

Key Terms

biologics license application, rolling review, comparative oncology, phase 2b, +3 more

7 terms

biologics license application regulatory

"announced that it has formally initiated a Biologics License Application (BLA) submission"

A biologics license application is a formal request submitted to regulatory authorities seeking approval to market a new biological medicine, such as vaccines or treatments made from living organisms. It is a comprehensive review process that evaluates the safety, effectiveness, and manufacturing quality of the product. For investors, receiving approval signals that a biological therapy can be sold to the public, potentially leading to revenue growth and market success.

rolling review regulatory

"submitted the Non-Clinical and the Chemistry, Manufacturing, and Controls (CMC) modules of the BLA to FDA, along with a request for Rolling Review"

A rolling review is a regulatory process where health authorities examine data on a drug or vaccine as it becomes available instead of waiting for a complete file at the end. For investors, this can speed up the timeline to approval and reduce uncertainty because regulators assess progress in real time—think of reading and approving chapters of a book as they’re finished rather than waiting for the whole manuscript, which can bring forward potential market access and revenue.

comparative oncology medical

"review new Comparative Oncology OST-HER2 biomarker data generated from the Company's Phase 2b human clinical trial"

Comparative oncology studies cancer across different species—most often using naturally occurring tumors in pets like dogs—to learn how cancers behave and respond to treatments in ways that mirror human disease. For investors, it matters because this cross-species testing can speed up drug development, reveal which therapies are likely to work, and lower the risk and cost of bringing new cancer treatments to market, much like using a rehearsal to improve a final performance.

phase 2b medical

"OST-HER2 Phase 2b human clinical trial and OST-HER2 trial in spontaneous osteosarcoma in canines"

Phase 2b is a stage in the development of a new medicine or treatment where researchers test its effectiveness and safety in a larger group of people. This step helps determine whether the treatment works well enough to move forward and if it has manageable side effects, which is important for investors because successful results can lead to potential approval and market opportunity.

regenerative medicine advanced therapy regulatory

"updated its Regenerative Medicine Advanced Therapy (RMAT) designation requests to FDA"

Regenerative Medicine Advanced Therapy (RMAT) is a U.S. regulatory designation for cell, gene, and tissue‑based therapies intended to treat serious or life‑threatening conditions; it gives developers a “fast lane” with more frequent agency interaction and eligibility for accelerated review pathways. For investors, an RMAT label signals that a therapy may reach market faster and face less regulatory uncertainty than a standard program, which can raise the potential value and reduce timeline risk—though it is not a guarantee of approval.

rare pediatric disease designation regulatory

"has received Rare Pediatric Disease Designation (RPDD) from FDA"

A rare pediatric disease designation is an official regulatory status given to a drug or therapy that targets a serious or life‑threatening condition primarily affecting children and is uncommon in the population. It matters to investors because the status often brings financial and development perks — such as tax credits, reduced fees, faster review and periods of market protection — which can lower costs, speed approval and improve the commercial outlook; think of it as a VIP pass that makes bringing a scarce, child‑focused treatment to market easier and potentially more profitable.

priority review voucher regulatory

"it will become eligible to receive a Priority Review Voucher (PRV) that it intends to sell"

A priority review voucher is a transferable regulatory incentive that lets a company move a future drug or device application to the front of the review line, shortening the review period by several months. For investors it matters because the voucher can speed up market access for a high-value product or be sold to other companies for significant cash, acting like a tradable fast-pass that can accelerate revenue or create immediate financial upside.

AI-generated analysis. Not financial advice.

• Request for FDA Rolling Review submitted to FDA on January 30, 2026
• Non-Clinical and CMC BLA modules submitted to FDA
• At FDA's request, Type D Meeting expected in March 2026 to review Comparative Oncology biomarker data from patients treated in OST-HER2 Phase 2b human clinical trial and OST-HER2 trial in spontaneous osteosarcoma in canines
• Final BLA clinical module expected to be submitted to FDA by end of March 2026 after Type D Meeting
• Regenerative Medicine Advanced Therapy (RMAT) designation requests update submitted to FDA with recent biomarker data
• Company remains on track to be eligible to receive Priority Review Voucher under Rare Pediatric Disease Designation (RPDD) with approval anticipated by September 30, 2026

New York, New York--(Newsfile Corp. - February 2, 2026) - OS Therapies Inc. (NYSE American: OSTX) ("OS Therapies" or "the Company"), the world leader in listeria-based cancer immunotherapies, today announced that it has formally initiated a Biologics License Application (BLA) submission to the U.S. Food & Drug Administration (FDA) for OST-HER2 in the prevention or delay of recurrent, fully resected, pulmonary metastatic osteosarcoma ("Human Metastatic Osteosarcoma"). The Company has submitted the Non-Clinical and the Chemistry, Manufacturing, and Controls (CMC) modules of the BLA to FDA, along with a request for Rolling Review. At FDA's invitation following a December 2025 Type C Meeting, the Company has requested a Type D Meeting to review new Comparative Oncology OST-HER2 biomarker data generated from the Company's Phase 2b human clinical trial in Human Metastatic Osteosarcoma and a similar trial of OST-HER2 in spontaneous osteosarcoma in canines (the "OST-HER2 Comparative Oncology Data"). The Company expects to submit the clinical BLA module that will rely upon the OST-HER2 Comparative Oncology Data by the end of March 2026, keeping it on schedule to be eligible to receive approval by September 30, 2026.

"We are delighted in the FDA's interest in reviewing OST-HER2 Comparative Oncology Data," said Paul Romness, MPH, Chairman & CEO of OS Therapies. "There is strong demand for compassionate use of OST-HER2 from the patient community, underscoring the urgent need for new therapies in Human Metastatic Osteosarcoma. We remain committed to bringing OST-HER2 to market as expeditiously as possible and are grateful for FDA's engagement as we finalize the biomarker data package that will be submitted as part of Type D meeting preparations to support our request for a BLA under the Accelerated Approval Program."

Concurrent with this announcement, the Company announced it has updated its Regenerative Medicine Advanced Therapy (RMAT) designation requests to FDA with recent biomarker data. RMAT designation typically shortens the timeframe granted for review of a BLA submission significantly from the standard timelines, expediting the time to patient access.

OST-HER2 has received FDA Orphan Disease Designation (ODD) and Fast Track Designation from FDA & EMA and has received Rare Pediatric Disease Designation (RPDD) from FDA. Under the RPDD program, if the Company receives Accelerated Approval prior to September 30, 2026, it will become eligible to receive a Priority Review Voucher (PRV) that it intends to sell. The most recent PRV sale, valued at $200 million, occurred in January 2026.

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 completing submission of a BLA to the U.S. FDA for OST-HER2 in osteosarcoma in March 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 ChenElev8 New Media
media@ostherapies.com 

https://x.com/OSTherapies
https://www.instagram.com/ostherapies/
https://www.facebook.com/OSTherapies/
https://www.linkedin.com/company/os-therapies/

To view the source version of this press release, please visit https://www.newsfilecorp.com/release/282344

FAQ

What did OS Therapies (OSTX) submit to the FDA on January 30, 2026?

The company submitted a request for Rolling Review and the Non‑Clinical and CMC BLA modules. According to the company, these filings start the rolling BLA process and precede submission of the clinical module planned for end of March 2026.

When is the FDA Type D meeting for OST-HER2 and what will be reviewed?

A Type D meeting is expected in March 2026 to review OST-HER2 comparative oncology biomarker data. According to the company, the meeting will cover Phase 2b human trial data and a spontaneous canine osteosarcoma trial to support the clinical BLA module.

What is OS Therapies' timeline to submit the OST-HER2 clinical BLA module (OSTX)?

The company expects to submit the clinical BLA module by the end of March 2026. According to the company, this submission will rely on comparative oncology biomarker data reviewed at the planned Type D meeting.

How could OSTX become eligible for a Priority Review Voucher (PRV)?

If OST-HER2 receives Accelerated Approval before September 30, 2026, the company would be eligible for a PRV. According to the company, it intends to sell any PRV obtained under the Rare Pediatric Disease Designation program.

What regulatory designations does OST-HER2 currently hold for OSTX?

OST-HER2 holds FDA Orphan Disease Designation, FDA and EMA Fast Track Designation, and FDA Rare Pediatric Disease Designation. According to the company, RMAT designation requests were updated with recent biomarker data to potentially expedite review timelines.