OS Therapies a clinical-stage biotechnology company focused on developing immunotherapies and targeted drug conjugates to treat cancer, has provided a comprehensive update to the market regarding its recent achievements and plans for the future. This announcement comes on the heels of a breakthrough moment for the company, as they seek to make significant strides in treating osteosarcoma, a rare and aggressive bone cancer. With a focus on advancing their OST-HER2 program, OS Therapies has shared positive clinical data, financial developments, and updates on their strategic direction.
A Milestone Month for OS Therapies
January 2025 marked a pivotal month in the history of OS Therapies, with significant progress made in both clinical and corporate fronts. According to Paul Romness, MHP, Chairman and CEO, the company’s journey began with a deeply personal connection: a loved one’s diagnosis of osteosarcoma. This experience illuminated the urgent need for better therapeutic options, especially when the standard treatments fail.
With this mission in mind, OS Therapies has been working tirelessly to develop innovative therapies that may offer a lifeline to osteosarcoma patients facing metastasis—a challenge that remains with a poor long-term prognosis for many. The data generated from their Phase 2b trial of OST-HER2 has provided a beacon of hope, suggesting the potential for a radical shift in the way osteosarcoma is treated, and possibly extending survival for patients who otherwise face grim outcomes.
Romness emphasized the importance of staying laser-focused on their mission: “We started OS Therapies because someone very close to my family developed osteosarcoma… We intend to stay laser-focused on our mission of bringing this therapy to market so that when the next family gets the devastating news of an osteosarcoma diagnosis, they’ll know that treatment options might exist.”
Financial Update and Capital Raising Efforts
In another major development, OS Therapies announced a successful completion of a $7.1 million financing round in mid-January 2025. This round, known as the “Preferred Round,” is designed to provide the company with the necessary funds to navigate the regulatory approval process for OST-HER2, focusing on the prevention of metastases in osteosarcoma. This capital is in addition to the $6 million raised in the company’s initial public offering (IPO) in August 2024. Combined, these efforts have provided OS Therapies with $13.1 million in funding over the past six months.
This funding will be allocated to several key initiatives, including:
- Final payments for the OST-HER2 osteosarcoma trial, including any non-clinical work required by the FDA.
- Commercial manufacturing preparations for FDA approval and product launch.
- Strategic and operational costs related to regulatory correspondence with the FDA and the European Medicines Agency (EMA).
- Commercial launch preparations for OST-HER2.
- Acquisition of the Listeria monocytogenes platform from Ayala, which strengthens the company’s immunotherapy capabilities.
- Corporate overhead costs.
However, the terms of the Preferred Round include a six-month capital raising restriction, as well as limitations on selling shares under the company’s Equity Line of Credit (ELOC) if the stock price is below $12.00. Additionally, warrants issued in connection with this financing round contain forced exercise provisions when the company’s stock price exceeds this threshold.
As a part of this financing round, OS Therapies also appointed Karim Galzahr to its Board of Directors to guide the company toward value creation for shareholders. The financing was predominantly supported by pre-IPO investors, including key backers from the osteosarcoma community, marking a strong commitment to the company’s mission.
Regulatory Progress and Clinical Achievements with OST-HER2
A significant milestone was achieved on January 15, 2025, when OS Therapies announced that its Phase 2b clinical trial for OST-HER2 met the primary endpoint with statistical significance. The trial aimed to evaluate the ability of OST-HER2 to prevent the recurrence of metastatic osteosarcoma after lung metastasis resection. The data revealed promising results when compared to the best available historical control group, demonstrating superior survival rates for OST-HER2-treated patients at both 12-month and 24-month follow-up intervals.
Key findings from the trial include:
- 33% of OST-HER2-treated patients were “Responders” at 12 months, compared to 20% in the historical control group.
- A greater proportion of OST-HER2-treated patients survived at 12 months (91% vs. 80%) and 24 months (61% vs. 40%) compared to the control group.
- Notably, 100% of patients who were disease-free at 12 months were alive at the 12-month, 18-month, 24-month, and 30-month timepoints.
OST-HER2 also demonstrated an excellent safety profile, with minimal side effects reported. These results are significant, as they suggest that OST-HER2 may be a viable option for patients with osteosarcoma, a disease with limited treatment options once metastasis occurs.
The company is preparing for additional regulatory discussions with the FDA regarding submission for accelerated or full approval. One critical step in this process is the creation of a matched historical external control arm, which will be used to demonstrate clinical efficacy and support regulatory approval.
Regulatory Path and FDA Approval Expectations
OS Therapies continues to engage with the FDA and expects to submit a Biologics License Application (BLA) for OST-HER2 in the first half of 2025. The company is optimistic that they will receive approval by late 2025 or early 2026.
which would be further supported by the FDA’s sunsetting Priority Review Voucher (PRV) program, available through the Rare Pediatric Disease Designation (RPDD) granted to OST-HER2 in 2021. If approved under the PRV program, the company could receive non-dilutive capital in the range of $150 million, which would greatly benefit OS Therapies as it expands its reach and commercial activities.
Acquisition of New Clinical Assets from Ayala
On January 29, 2025, OS Therapies announced an agreement to acquire clinical and intellectual property assets from Ayala, a move that strengthens the company’s portfolio. Through this acquisition, OS Therapies gained rights to two promising immunotherapy candidates, ADXS-503 and ADXS-504, which target lung and prostate cancer, respectively. These acquisitions not only provide new clinical-stage assets but also reduce expected near-term cash milestones and lower royalty rates, improving the company’s financial outlook.
This move further establishes OS Therapies as a leader in Listeria-based immunotherapies—a class of cancer treatments that has shown significant potential. The acquisition will allow the company to expand its therapeutic pipeline, offering a broader range of treatment options for patients with cancers that currently have limited treatment alternatives.
Strategic Focus Moving Forward
OS Therapies remains committed to the development of OST-HER2, with a focus on expanding its application beyond osteosarcoma. The company plans to explore the potential of OST-HER2 in other HER2-related cancers and further investigate the Listeria-based therapies ADXS-503 and ADXS-504 in lung and prostate cancer. OS Therapies also plans to advance its tunable drug conjugate platform, which uses pH-sensitive linkers to create more effective and targeted therapies with reduced side effects.
OS Therapies is making remarkable progress in both its clinical trials and corporate strategy. With key financial investments, regulatory advancements, and the acquisition of valuable new assets, the company is poised to become a leader in the field of cancer immunotherapy. Their commitment to innovation, especially in the area of osteosarcoma treatment, offers hope to patients and their families, with the potential for significant breakthroughs in the coming years.