ADDED
This report contains additional trade names, trademarks and service marks owned by their respective owners.
Solely for convenience, trademarks and trade names referred to in this annual report may appear without the or symbols, but such an omission is not intended to indicate that we will not assert, to the fullest extent under applicable law, our rights, or that the applicable owners will not assert their rights, to these trademarks and trade names.
We are currently seeking to answer the call for new treatments that will prevent metastasis and the recurrence of metastases with our lead core product candidate OST-HER2 (also known as OST31-164), a cancer immunotherapy product candidate that produces a cellular immune response against the cancer antigen HER2.
In 2021, we opened a clinical study to produce data for the U.S.
Food and Drug Administration (FDA) to evaluate the safety and efficacy of OST-HER2 in patients after resection of recurrent Osteosarcoma, which achieved full enrollment of 41 patients in October 2023.
In the first quarter of 2025, we announced that our Phase IIb clinical trial achieved its primary endpoint with statistical significance.
In October 2025, we announced final two-year overall survival data from the Phase IIb trial, in which 75% (27 of 36 evaluable patients) of OST-HER2-treated patients achieved two-year overall survival from the most recent pulmonary resection, compared with 40% in historical control patients (p 0.0001).
In January 2026, we announced positive immune biomarker data from the Phase IIb trial indicating that activation of immune blood biomarkers in the interferon gamma pathway correlated with, and was predictive of, overall survival, distinguishing long-term survivors ( two years) from short-term survivors ( one year).
These biomarker findings are based on exploratory analyses and have not been validated as surrogate endpoints for clinical benefit.
Based on the totality of the data generated to date, including the observed survival outcomes, safety profile and the significant unmet medical need in this patient population, we intend to engage with the FDA regarding potential regulatory pathways for OST-HER2.
REMOVED
This report contains additional trade names, trademarks and service marks of other companies that are the property of their respective owners.
Solely for convenience, trademarks and trade names referred to in this annual report appear without symbol, but those references are not intended to indicate that we will not assert, to the fullest extent under applicable law, our rights, or that the applicable owners will not assert their rights, to these trademarks and trade names.
We are currently seeking to answer the call for new treatments with our lead core product candidate OST-HER2 (also known as OST31-164).
We intend to expand our pipeline beyond Osteosarcoma with this product candidate into other solid tumors with the same recurrence mechanism of action, including breast, esophageal and lung cancers.
With the addition of our OST-Tunable Drug Conjugate (OST-tADC) platform, which we consider to be a next generation antibody-drug conjugate (ADC) technology, we will be targeting ovarian, lung and pancreatic cancers.
Furthering our founding mission, we also intend to investigate clinical indications for OST-tADC in Osteosarcoma.
We believe that there have not been any new treatments approved by the U.S.
Food and Drug Administration (FDA) for Osteosarcoma for more than 40 years.
In humans, Osteosarcoma is an extremely rare cancer that primarily affects children, teenagers and young adults generally under 40 years of age.
We are not aware of any competing adjuvant therapy for Osteosarcoma to be tested in children that is further along in the development process than OST-HER2.