The Food and Drug Administration (FDA) granted accelerated approval to a new dosing regimen of 400 mg every six weeks for pembrolizumab across all currently approved adult indications, in addition to the current 200 mg every three weeks dosing regimen.

The approval was based on pharmacokinetic modelling and exposure-response analyses that compared the predicted exposure of pembrolizumab 400 mg every six weeks to observed exposures of pembrolizumab in patients who received pembrolizumab at 2 mg/kg every three weeks, 200 mg every three weeks, and 10 mg/kg administered every two weeks.

The pharmacokinetic modelling were supported by additional exposure-response analyses across the pembrolizumab development program and an interim analysis of pharmacokinetics and overall response rate (ORR) in a cohort of patients (Cohort B) enrolled in study KEYNOTE-555 (NCT03665597).

Cohort B of Study KEYNOTE-555 was an international, single-arm, multi-centre study that enrolled 101 patients with advanced or metastatic melanoma who had not received prior PD-1, PD-L1, or CTLA-4 inhibitors (other than CTLA-4 inhibitors in the adjuvant setting).

The ORR was 39% (95% CI: 24, 55) in the first 44 patients enrolled in KEYNOTE-555.

Source: The Food and Drug Administration (FDA)