The clinical study, which had the first patient dosed in December 2018, evaluated the safety and clinical efficacy of olinvacimab, the Company's anti-VEGFR2 (Vascular Endothelial Growth Factor Receptors) antibody candidate, in combination with  MSD's (Merck & Co., Inc., Kenilworth, NJ., USA) anti-PD-1 therapy, KEYTRUDA® (pembrolizumab). A total of 11 patients were recruited and divided into two cohorts. The low-dose cohort (five patients) received a 12mg/kg weekly dose of olinvacimab, and the high-dose cohort (six patients) received a 16mg/kg weekly dose of olinvacimab. All patients equally received a 200mg flat dose of pembrolizumab every three weeks. 

In December 2020, PharmAbcine presented the highly encouraging interim data of the study at SABCS (San Antonio Breast Cancer Symposium). In the high-dose olinvacimab cohort, an ORR (Overall Response Rate) of 50% was reported in three of six patients, and a DCR (Disease Control Rate) of 67% was reported in four out of six patients. Notably, one patient in the high-dose cohort showed CR (Complete Response) in the target lesion but was labeled as PR (Partial Response) due to a tumor remaining in a non-target lesion.

The last patient, who just completed 35 cycles of olinvacimab and pembrolizumab combo treatment, will receive olinvacimab in monotherapy as compassionate use starting from early March 2022. In addition, another patient, who showed CR in the target lesion, has already been receiving olinvacimab as compassionate use since August 2021 and is in stable condition.

The encouraging data from this study provided strong scientific rationale for PharmAbcine to proceed to a Phase IIa study. In September 2021, PharmAbcine received Australian HREC (Human Research Ethics Committee) clearance to commence the subsequent Phase IIa combo trial designed to evaluate the clinical efficacy of 16mg/kg weekly dose of olinvacimab in combination with 200mg of pembrolizumab in a larger population setting. The study had the first patient dosing in December 2021, and is actively recruiting patients.

"The patients, who continued to receive the treatment since the interim data presentation in 2020, showed no serious adverse events," said Dr. Jin-San Yoo, CEO of PharmAbcine. "We are pleased to report this critical milestone and looking forward to getting the final report made available in the future,"

KEYTRUDA® is a registered trademark of Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA.