F-star Therapeutics, Inc. announced the publication of safety and efficacy results from Phase 1 trial of FS118 in patients with advanced cancer and PD-L1 resistance in Clinical Cancer Research, a journal of the American Association for Cancer Research. FS118 is a first-in-class tetravalent bispecific antibody binding to LAG-3 and PD-L1, resulting in the reversal of immune suppression. The Phase 1 trial is the first-in-human study of FS118 that is evaluating forty-three patients with locally advanced/metastatic cancer with a median of three prior regimens therapy and at least one anti-PD-L1 regimen.

Patients received intravenous FS118 monotherapy weekly with an accelerated dose titration design followed by 3+3 ascending dose expansion. Weekly administration was well tolerated, with no dose-limiting toxicities, and no serious adverse events relating to FS118. The recommended Phase 2 dose of FS118 was established at 10 mg/kg weekly.

The pharmacodynamic activity was prolonged throughout dosing as demonstrated by sustained, increased levels of both soluble LAG-3 and peripheral effector cells. A disease control rate (DCR) of 54.8% was observed in patients receiving 1 mg/kg or greater who had acquired resistance to PD-L1-targeted therapy.