Full Press Release Details
OS Therapies Announces
EMA Initiates Rolling Review of Conditional Marketing Authorization Application for OST-HER2 in the Prevention or Delay of Recurrence
in Fully Resected Pulmonary Metastatic Osteosarcoma
Conference call scheduled for Thursday, April
30, 2026, at 8:30 am ET to review new OST-HER2 immune pharmacodynamic biomarker response (seroconversion) data and review regulatory successes
validating the OST-HER2 approach. Participants will include strategic advisors Dr. Craig Eagle and Dr. Bob Langer, and Osteosarcoma key
opinion leader Dr. Peter Anderson from Cleveland Clinic.
30, 2026 - OS Therapies, Inc. (NYSE American: OSTX) ("OS Therapies" or "the Company"), the world leader
in gene-edited, listeria-based cancer immunotherapies, today announced that the European Medicines Agency (EMA)'s Committee for
Advanced Therapy (CAT), in conjunction with the Committee for Medicinal Products for Human Use (CHMP) and Pharmacovigilance Risk Assessment
Committee (PRAC), has initiated Continuous Evaluation ("Rolling Review") of the OST-HER2 Conditional Marketing Authorisation
(CMA) request regulatory dossier for the prevention of recurrence in fully resected, pulmonary metastatic osteosarcoma.1 The
Company also announced that it was selected into EMA's Raw Data Pilot programme that will done in concert with the EMA Scientific
Advice Working Party (SAWP).
Australia Therapeutic Goods Association (ATGA)
has also invited the OS Therapies to make an application for Provisional Determination, the Australian equivalent of a Conditional Marketing
Authorisation of the OST-HER2 regulatory dossier, and is expected to make a decision on rolling review following the receipt of the Clinical
Trial Notification (CTN) for the confirmatory Phase 3 trial later this quarter that will position the OS Therapies to initiate the confirmatory
Phase 3 in the third quarter of 2026.
"I am delighted with the regulatory
interactions OS Therapies has had to date, and I look forward to supporting OS Therapies in upcoming meetings with U.S. and U.K regulators,"
said Dr. Craig Eagle, strategic advisor for OS Therapies.
OST-HER2 Immune Pharmacodynamic Biomarkers
Conference Call Details
Title: OS Therapies (NYSE: OSTX) | Conference
Call: OST-HER2 immune pharmacodynamic response biomarkers
Date: April 30th, 2026
Time: 8:30 AM Eastern Time
Registration Link: https://zoom.us/webinar/register/WN_Xlmj7kdNTH6C0MA_xdwiiQ
EMA OST-HER2 Rolling Review Status
OS Therapies and EMA
have agreed that 3-year overall survival data will serve as the basis to complete evaluation of the CMA request. The Company's
recently submitted clinical efficacy data includes 2-year overall survival data, with EMA requesting updated 2.5-year overall survival
data that will be available by the middle of the second quarter of 2026, and 3-year overall survival data that will become available
early in the fourth quarter of 2026, which will complete the CMA submission. The Company anticipates a potential CMA decision by EMA
in the fourth quarter of 2026. Market access interactions related to reimbursement with the UK's NICE and EMA Health Technology
Assessment (HTA) processes have commenced simultaneously to minimize the time between regulatory approval(s) and patient access to treatment.
International regulatory coordination has also commenced under the EMA FDA Information Sharing programme2.
Additionally, the Company
has been granted Advanced Therapy Medicinal Product designation from the U.K. Medicines and Healthcare products Regulatory Agency (MHRA)3
by virtue of its reciprocal designation agreement with EMA.
"We are grateful for EMA and ATGA's
strong support of our OST-HER2 program as we urgently work to improve outcomes for patients facing this rare and deadly pediatric cancer,"
said Paul Romness, Chair and Chief Executive Officer of OS Therapies. "With all currently available data submitted and key regulatory
alignment achieved, we are advancing toward early market access via Conditional Marketing Authorizations in Europe, the U.K., and Australia,
as well as a U.S. Biologics License Application (BLA) under Accelerated Approval. Following our recent ATMP designation in Europe, we
believe peak European sales could exceed $300 million annually, with the potential to generate more than $50 million in sales beginning
in 2027." Mr. Romness continued: "We have aligned with EMA and ATGA on the provisional design of our global confirmatory Phase
3 trial that is required to be initiated prior to being granted early market access, including 3-year overall survival as the primary
efficacy endpoint. 3-year overall survival will also be the efficacy endpoint that will serve as the basis for potential early market
access in the U.S., U.K., Europe, and Australia. This gives us strong confidence as we head into upcoming FDA and MHRA meetings, while
reinforcing the growing recognition of our pharmacodynamic biomarker response seroconversion data as a meaningful surrogate for the key
overall survival efficacy endpoint, further supporting our global regulatory pathway. We are delighted that immunotherapies are becoming
more central in the approach to treating cancers globally, which bolsters OST-HER2 and the rest of our attenuated listeria monocytogenes
platform candidates."
"With the significant momentum we now
have surrounding OST-HER2 in osteosarcoma, we are actively working to be prepared for the time when resources become available to advance
our exciting listeria monocytogenes platform pipeline," said Robert Petit, PhD, Chief Medical and Scientific Officer at OS Therapies.
"Based upon the extensive biomarker work we have done to date on the OST-HER2 osteosarcoma program, we are now positioned to generate
congruent data for the OST-504 castration-resistant prostate cancer program. Additionally, following significant advancement in the exciting
KRAS-targeted antibody pancreatic cancer field with important clinical data showing significant survival benefit, we have identified that
our promising Phase 2 non-small cell lung cancer (NSCLC) candidate OST-503 was constructed to target all KRAS G12 position-related antigen
mutations, which represents 76% of all KRAS mutations in cancer. As a result, we believe OST-503 could represent a highly complementary
approach to KRAS-target antibodies currently in development."
OST-HER2 has received Orphan Drug Designation
(ODD), Fast Track Designation (FTD) and Rare Pediatric Disease Designation (RPDD) from the FDA, and ODD, FTD and ATMP from the EMA. Under
the RPDD program, if the Company receives a BLA in the United States, it will become eligible to receive a Priority Review Voucher (PRV)
that it intends to sell. The Company is seeking to obtain a BLA under the Accelerated Approval Program for OST-HER2 in osteosarcoma in
the second half of 2026, in addition to CMAs in Europe, the U.K. and Australia.
Upcoming 2nd Quarter Milestones
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 is designed
to target two mutated extracellular epitopes and one mutated intracellular epitope of the HER2 oncogene, requiring only one of these three
epitopes to be present in a tumor (or micro-metastasis) to trigger the desired immune response. OST-HER2 has received Orphan Drug Designation
(ODD), Fast Track Designation (FTD) and Rare Pediatric Disease Designation (RPDD) from the U.S. Food & Drug Administration and has
received ODD, FTD and ATMP from the 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 clinically significant benefit
in the 12-month event free survival (EFS) primary endpoint of the study and the overall survival (OS) secondary endpoint. The Company
anticipates receiving a Biologics License Application (BLA) from the U.S. FDA for OST-HER2 in osteosarcoma in 2026 and, if approved, would
become eligible to receive a Priority Review Voucher that it could then sell. The Company also anticipates receiving Conditional Marketing
Authorisations from the U.K.'s Medicines and Healthcare products Regulatory Agency and the EMA for OST-HER2 in 2026. 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.
The Company also anticipates reading out data from a Phase 1b study of OST-504 in castration resistant prostate cancer in the first half
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
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