PharmAbcine Inc., a clinical-stage biotech company focusing on the development of next generation antibody therapeutics, announced it has dosed the first patient in its Phase II clinical trial evaluating the combination of olinvacimab, PharmAbcine‘s anti-VEGFR2 (Vascular Endothelial Growth Factor Receptors) antibody, and KEYTRUDA® (pembrolizumab), MSD’s anti-PD-1 molecule, for the treatment of mTNBC (metastatic Triple-Negative Breast Cancer) in Australia.
The Phase II clinical trial is currently open and actively recruiting patients. It is an open-label and multicenter trial that will enroll 36 immuno-oncology drug naïve mTNBC patients regardless of their PD-L1 expression level. The study is designed to evaluate the clinical efficacy, safety, pharmacodynamics, and the expression level of VEGFR2. The enrolled patients will be treated with 16mg/kg of olinvacimab every week and 200mg of pembrolizumab every 3 weeks for up to 35 cycles (approximately 2 years).
Both companies decided to initiate this study based on the promising clinical data obtained from the Phase Ib olinvacimab and pembrolizumab study in mTNBC which is still ongoing in Australia. According to the interim result presented at SABCS (San Antonio Breast Cancer Symposium) 2020, olinvacimab in combination with pembrolizumab showed a clear safety profile and encouraging efficacy data, including 50% ORR (Overall Response Rate) and 67% DCR (Disease Control Rate) in the high-dose olinvacimab (16mg/kg) cohort (n=6pts). In addition, one patient in PR (Partial Response) showed CR (Complete Response) in the target lesion and another PR patient showed CR in a non-target lesion.
mTNBC is a highly malignant type of cancer that shows a high recurrence rate within the first five years after diagnosis. mTNBC accounts for 15-20% of all breast cancers and shows a 5-year survival rate of approximately 11%. Unlike other breast cancers, mTNBC does not express estrogen or progesterone receptors or HER2 (human epidermal growth factor receptor 2), and it does not respond to existing cancer drugs designed to target these markers. mTNBC is very difficult to treat, and there are very few FDA approved treatment options for these patients.