Swedish biotech company BioInvent International AB (STO:BINV) on Monday reported encouraging interim data from an ongoing Phase 2a study evaluating BI-1808, a novel immuno-oncology candidate, in combination with KEYTRUDA (pembrolizumab) in patients with recurrent ovarian cancer who progressed after platinum-based therapy.

The combination achieved a 24% overall response rate, compared with an 8% response rate for pembrolizumab monotherapy reported in the KEYNOTE-100 study, and demonstrated a favourable safety and tolerability profile.

As of 18 December 2025, 23 patients had been enrolled, with 17 evaluable patients showing a disease control rate of 65%, including four partial responses and seven cases of stable disease, some lasting beyond eight months. Exploratory analyses indicated activity in high-grade serous and clear cell ovarian cancer subtypes. Based on these results, BioInvent plans to expand the Phase 2a cohort by enrolling an additional 20 patients in these subtypes, with a data readout expected in the second half of 2026.

BioInvent has had a clinical trial collaboration and supply agreement with MSD, a tradename of Merck & Co Inc (NYSE:MRK), since August 2021 to evaluate the combination of BI-1808 and KEYTRUDA (pembrolizumab), MSD's anti-PD-1 therapy.