OS Therapies Announces Last Patient Enrolled in OST-HER2 Osteosarcoma Phase 2b Clinical Trial Receives Last Treatment Dose

Rhea-AI Summary

OS Therapies (NYSE American: OSTX) announced the completion of treatment for the final patient in its Phase 2b clinical trial of OST-HER2 for recurred, resected Osteosarcoma. The trial, AOST-2121 (NCT04974008), enrolled 41 patients across 21 U.S. sites. The primary endpoint is 12-month Event Free Survival, with final evaluation expected in early Q4 2024. OST-HER2 is a Listeria-based immunotherapeutic vaccine designed to prevent metastasis and increase survival in Osteosarcoma patients.

The study aims to demonstrate efficacy in patients with high recurrence risk. Topline data, including 12-month Event Free Survival and interim 2-year Overall Survival, is anticipated in Q4 2024. This trial is significant as no new FDA-approved treatments have improved Osteosarcoma outcomes in over 40 years.

Positive

• Completion of treatment for the final patient in Phase 2b trial of OST-HER2
• Full enrollment achieved with 41 patients across 21 U.S. clinical sites
• Potential to be the first FDA-approved treatment improving Osteosarcoma outcomes in over 40 years
• Topline data expected in Q4 2024, including 12-month Event Free Survival and interim 2-year Overall Survival

Negative

• Final results and FDA approval still pending, with no guarantee of success
• Long timeline for full data analysis, with final patient evaluation not expected until early Q4 2024

Medical Research Analyst

The completion of OST-HER2's Phase 2b trial marks a significant milestone in Osteosarcoma treatment research. With 41 patients treated across 21 U.S. sites, this study's scope is substantial for a rare cancer. The 12-month Event Free Survival primary endpoint, alongside Overall Survival data, could provide important insights into OST-HER2's efficacy.

The immunotherapeutic approach of OST-HER2, targeting HER2 expression in tumors, represents an innovative strategy in a field that hasn't seen major advancements in over 40 years. If successful, this could potentially fill a critical treatment gap for recurrent Osteosarcoma patients, who currently lack approved adjuvant therapies in the U.S.

Investors should closely monitor the Q4 2024 data readout, as positive results could significantly impact OS Therapies' market position and potentially lead to accelerated FDA approval discussions.

Oncology Doctor

The completion of OST-HER2's Phase 2b trial in recurrent Osteosarcoma is a beacon of hope in a challenging therapeutic landscape. The trial's design, focusing on patients with a high likelihood of recurrence, addresses a critical unmet need in Osteosarcoma treatment.

The Listeria-based vector approach is particularly intriguing, as it harnesses both innate and adaptive immune responses. This dual-action mechanism could potentially offer a more robust and durable anti-tumor effect compared to traditional therapies.

However, it's important to temper enthusiasm with caution. While the 16-dose regimen over 52 weeks is comprehensive, it may pose adherence challenges. Additionally, the true test will be in the long-term Overall Survival data, which won't be fully mature until the 36-month mark. The interim data expected in Q4 2024 will provide valuable insights, but won't tell the complete story.

Financial Analyst

The completion of OS Therapies' Phase 2b trial for OST-HER2 is a significant milestone for the company. With no new FDA-approved treatments for Osteosarcoma in over four decades, a successful outcome could position OS Therapies as a pioneer in this underserved market.

Investors should note that the topline data expected in Q4 2024 could be a major catalyst for the stock. Positive results may lead to accelerated FDA discussions and potential partnerships, significantly enhancing the company's value proposition.

However, it's important to consider the financial implications of bringing a novel therapy to market, especially for a rare disease. While the unmet need presents a significant opportunity, the patient population may impact revenue potential. Additionally, the company's pipeline beyond Osteosarcoma, including plans for breast cancer trials, will be critical for long-term growth prospects.

NEW YORK--(BUSINESS WIRE)-- OS Therapies Incorporated (NYSE American: OSTX) (“OS Therapies” or “the Company”), an ADC and Immunotherapy research and clinical-stage biopharmaceutical company, today announced that the last patient (Patient #41) enrolled in the AOST-2121 clinical trial (NCT04974008) of OST-HER2 in recurred, resected Osteosarcoma (OS) - has received its last treatment dose. This last patient is expected to complete its final radiological imaging evaluation as part of the 12-month Event Free Survival primary endpoint analysis by early in the fourth quarter of 2024. Concurrently, the Company will close all clinical trial sites and lock the database in preparation for data analysis and topline data readout that is expected to be announced in the fourth quarter of 2024.

OST-HER2, a biologic therapeutic candidate, is a Lm (Listeria monocytogenes) vector-based off-the-shelf immunotherapeutic vaccine designed to prevent metastasis, delay recurrence, and increase overall survival in patients with Osteosarcoma. The AOST-2121 study is designed to demonstrate efficacy in patients who have already had recurrent disease and are highly likely to recur. A total of 16 OST-HER2 doses are administered once every three weeks, with a follow-up approximately four weeks after the final dose is administered, for a total of 52 weeks study. Radiographic evaluation of recurrence is evaluated throughout treatment. The proposed OST-HER2 mechanism of action is based on innate and adaptive immune stimulating responses activated by the Lm vector. This treatment generates T-cells that can eliminate or slow potential micro-metastases that can grow into recurrent Osteosarcoma. T-cell responses target HER2 expressed by the tumor and then kill the cell, releasing additional tumor targets. There are currently no approved adjuvant treatments for recurrent Osteosarcoma in the United States.

AOST-2121 has achieved full enrollment of 41 patients treated with OST-HER2 at 21 clinical trial sites across the United States. The primary endpoints for the AOST-2121 study are Event Free Survival (“EFS”’, defined as absence of recurrence of primary tumor or metastasis) at 12 months and Overall Survival at 36 months, with interim Overall Survival endpoints at 12 months and 24 months. Topline EFS data, interim 2-year OS data, as well as additional secondary data analyses are expected to be reported in the fourth quarter of 2024. We believe there have not been any novel therapeutic interventions approved by the FDA that have improved the clinical outcomes for patients with Osteosarcoma in over 40 years.

The addition of the data from this final patient, along with Patient #40, will enhance interim data announced in conjunction with ASCO 2024. This is in addition to previously reported Phase I clinical data in Breast cancer, which the Company plans to target after Osteosarcoma. We thank the patients, families, clinicians, researchers, assistants and the entire Osteosarcoma community for supporting this important and ground-breaking trial.

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. The Company has completed enrollment for a 41-patient Phase 2b clinical trial of OST-HER2 in resected, recurrent osteosarcoma, with results expected in the fourth quarter of 2024. OST-HER2 has completed a Phase 1 clinical study primarily in breast cancer patients, in addition to showing strong preclinical efficacy data in various models of breast cancer. In addition, OS Therapies is advancing its next generation Antibody Drug Conjugate (ADC) platform, known as tunable ADC (tADC), which features tunable, tailored antibody-linker-payload candidates. This platform leverages the Company’s proprietary silicone linker 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. Prospective investors are cautioned that any such forward-looking statements are not guarantees of future performance and involve risks and uncertainties, including those described under the section entitled “Risk Factors” of our Registration Statement on Form S-1 initially filed with the Securities and Exchange Commission (the “SEC”) on May 30, 2024, as well as any of our periodic reports filed with the SEC, and that actual results may differ materially from those indicated by such forward-looking statements. 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.

View source version on businesswire.com: https://www.businesswire.com/news/home/20240829924878/en/

Corporate and Media Contact:

Jack Doll

410-297-7793

Irpr@ostherapies.com



Investor Relations:

Dave Gentry

RedChip Companies, Inc.

1-407-644-4256

OSTX@redchip.com

Source: OS Therapies

FAQ

What is the current status of OS Therapies' (OSTX) OST-HER2 clinical trial for Osteosarcoma?

The last patient in OS Therapies' Phase 2b clinical trial (AOST-2121) for OST-HER2 in recurred, resected Osteosarcoma has received their final treatment dose. The trial has completed full enrollment of 41 patients across 21 U.S. clinical sites.

When will OS Therapies (OSTX) release topline data for the OST-HER2 Osteosarcoma trial?

OS Therapies expects to announce topline data, including 12-month Event Free Survival and interim 2-year Overall Survival, in the fourth quarter of 2024.

What are the primary endpoints of OS Therapies' (OSTX) AOST-2121 clinical trial?

The primary endpoints for the AOST-2121 study are Event Free Survival at 12 months and Overall Survival at 36 months, with interim Overall Survival endpoints at 12 and 24 months.

How does OS Therapies' (OSTX) OST-HER2 treatment work for Osteosarcoma patients?

OST-HER2 is a Listeria-based immunotherapeutic vaccine designed to prevent metastasis, delay recurrence, and increase overall survival in Osteosarcoma patients by stimulating innate and adaptive immune responses targeting HER2 expressed by the tumor.