OS Therapies Announces Positive Clinical Update from Ongoing Phase 2b Clinical Trial in Resected, Recurrent Osteosarcoma
OS Therapies (NYSE-A: OSTX) announced a positive update from its Phase 2b clinical trial for the immunotherapy OST-HER2 in resected, recurrent osteosarcoma patients. The trial achieved a 1-year event-free survival (EFS) rate of 32.5%, significantly higher than the 20% EFS rate for an unsuccessful comparator. The 1-year and 18-month overall survival (OS) rates were both 90.4%. Importantly, no grade 3, 4, or 5 treatment-related adverse events were reported among the 41 patients. Full enrollment is complete, with primary 12-month EFS and interim 12-month OS data expected by Q4 2024. OST-HER2 aims to prevent metastasis and recurrence while enhancing overall survival.
- 1-year EFS rate of 32.5% vs. 20% for comparator.
- 1-year and 18-month OS rates of 90.4%.
- No grade 3, 4, or 5 treatment-related adverse events.
- Full enrollment achieved with 41 patients across 21 sites.
- Phase 2b co-primary endpoint data expected by Q4 2024.
- OST-HER2 granted RPDD, ODD, and FTD by the FDA.
- Potential to become the first new osteosarcoma treatment in 40+ years.
- No data on long-term efficacy beyond 18 months yet.
- EFS improvement, while significant, still leaves a substantial recurrence risk.
- Final Phase 2b data and approval not expected until end of 2024 at the earliest.
- Current data primarily interim; full effectiveness and safety yet to be confirmed.
Insights
The clinical update for OST-HER2 in treating resected, recurrent osteosarcoma is highly significant. The reported 1-year Event-Free Survival (EFS) rate of 32.5% compared to the 20% EFS rate for the comparator highlights a marked improvement. This suggests a potential breakthrough, given that no novel therapeutic interventions for this condition have emerged in over 40 years.
The 1-year and 18-month Overall Survival (OS) rate of 90.4% is also noteworthy. Survival rates in this range indicate a strong efficacy profile, especially when considering the high-risk nature of the patient population. It's important to note that these figures are interim results and final data will be more telling.
The absence of Grade 3, 4, or 5 adverse events is a positive indicator of the treatment's safety profile. This tolerability can be important for patient compliance and overall treatment success. The mechanism of action, leveraging both innate and adaptive immune responses via a Listeria monocytogenes vector, is innovative and could offer a new pathway for treating osteosarcoma.
For investors, the FDA's designations (RPDD, ODD and FTD) enhance the treatment's development pathway, potentially accelerating its time to market and offering financial incentives. The upcoming data release in the fourth quarter of 2024 will be critical for evaluating the long-term viability and potential market impact of OST-HER2.
In summary, these interim results are promising both from a clinical and investment standpoint. The combination of efficacy, safety and regulatory support positions OST-HER2 as a strong candidate in a market with significant unmet needs.
The latest clinical update for OST-HER2 bodes well for OS Therapies from a financial perspective. The 32.5% 1-year Event-Free Survival (EFS) rate compared to the 20% of the comparator signifies a substantial improvement and strengthens the company's value proposition. Given the unmet need in the osteosarcoma market, positive interim results can attract more investment and partnerships.
OS Therapies’ current stock performance might see a boost from these interim results, but the real financial impact will be clearer after the final data release in Q4 2024. Investors should be cautious but optimistic, noting that these results are preliminary and subject to change.
Furthermore, the FDA designations (RPDD, ODD and FTD) not only facilitate a faster regulatory pathway but also offer market exclusivity and potential financial incentives. This reduces some investment risks and enhances the potential return on investment.
The absence of severe adverse events (Grade 3, 4, or 5) enhances the drug's appeal, making it likely to gain a better reception in the market if approved. Safety is a critical concern for investors, as adverse events can lead to increased costs and potential legal liabilities.
In conclusion, these interim results are financially promising, positioning OS Therapies for potential growth. However, investors should await the final data for a more comprehensive evaluation.
-
1-year Event Free Survival (EFS) of
32.5% vs.20% 1-year EFS for comparator -
Interim 1-year and 18-month Overall Survival (OS) of
90.4% - 0 Grade 3, 4 or 5 Treatment-related Adverse Events (AEs)
- 41 patient trial fully enrolled
- Primary endpoint 12-month EFS data and interim co-primary endpoint 12-month OS data to be released in the fourth quarter of 2024
- No novel therapeutic interventions for resected, recurrent osteosarcoma in 40+years
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 again. A total of 18 OST-HER2 doses are administered once every three weeks, for a total 51 weeks. 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 micrometastases that can grow into recurrent osteosarcoma. T cell responses home-in on 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
AOST-2121 has achieved full enrollment of 41 patients treated with OST-HER2 at 21 clinical trial sites across
The clinical updates reported today include:
-
1-year EFS rate of
32.5% vs.20% EFS rate for unsuccessful investigational therapeutic comparator1 -
1-year overall survival rate of
90.4% -
18-month overall survival rate of
90.4% - Treatment has been well tolerated and there have been no grade 3, 4 or 5 treatment-related adverse events reported for the 41 patients.
“OST-HER2’s strong safety profile supports its potential to become a practical adjuvant therapy to delay or prevent subsequent recurrences and improve overall survival in the very difficult challenge of recurrent osteosarcoma. Promoting innate and adaptive immune surveillance against lurking micrometastases could become a potentially powerful tool for oncologists as they seek to improve the quality of life and prolong survival of patients who have suffered from Osteosarcoma,” said Dr. Robert Petit, Chief Medical & Scientific Officer of OS Therapies. “OST-HER2 has the potential to significantly improve the standard of care in this difficult to treat patient population. In light of today’s encouraging clinical trial update, we are hopeful that final data coming in the fourth quarter of this year, combined with supplemental data that will follow in 2025, positions OST-HER2 to become available to help clinicians better protect people with difficult cancers like osteosarcoma.”
“With historical 1-year EFS estimated in the low-to-mid teens with the current standard of care, and the most recent investigational therapeutic comparator yielding 1-year EFS of
The FDA has granted Rare Pediatric Disease Designation (RPDD), Orphan Drug Designation (ODD), and Fast Track Designation (FTD) for OST-HER2 in Osteosarcoma.
References
- Lagmay JP, Krailo MD, Dang H, et al: Outcome of patients with recurrent osteosarcoma enrolled in seven Phase II trials through Children's Cancer Group, Pediatric Oncology Group, and Children's Oncology Group: learning from the past to move forward. J Clin Oncol. 2016;34:3031-8.
About Osteosarcoma
Osteosarcoma is a solid tumor of the bone that predominantly occurs in adolescents and young adults (AYA). Standard treatment includes surgery and chemotherapy. For patients with metastatic osteosarcoma or have recurrence after chemotherapy, the prognosis is poor.
About OS Therapies
OS Therapies, Inc. (NYSE-A: OSTX) is a clinical stage oncology company focused on the identification, development and commercialization of treatments for Osteosarcoma (OS) and other solid tumors. OST-HER2 is an immunotherapy leveraging the immune stimulatory effects of Listeria bacteria to initiate a strong immune response targeting the HER2 protein. The Company has fully-enrolled a 41-patient Phase 2b clinical trial of OST-HER2 in resected, recurrent osteosarcoma, with results expected in the fourth quarter of 2024. OS Therapies is also developing the next generations Antibody Drug Conjugate (ADC) platform tunable ADC (tADC) centered around tunable, tailored antibody-linker-payload candidates built around the Company’s unique silicone linker technology that allows for multiple payloads to be delivered per linker.
About OST-HER2
The OST-HER2 Lm vector platform technology has been administered to over 450 cancer patients in ongoing and completed clinical trials. AOST-2121 is a Phase IIB clinical trial intended to prevent or delay metastasis and improve Overall Survival (OS) in Osteosarcoma. OST-HER2 has already received Fast-Track, Orphan, and Rare Disease Designation (RDD). OST hopes to seek a Break-Through Designation (BTD) based on data from this Phase IIb clinical trial. OST31-164 has previously received USDA provisional approval for treatment of Osteosarcoma in canines. In a completed Phase III study in canines (n=180), early data demonstrated a clear separation of treated and untreated canine patients (p=.0007) in Overall Survival (OS) and Disease Progression.
For more information, please see the Company's website at www.ostherapies.com
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Source: OS Therapies, Inc.
FAQ
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