On April 28, the U.S. Food and Drug Administration (FDA) granted accelerated approval to a new dosing regimen for pembrolizumab (Keytruda)—400 mg every 6 weeks—across all currently approved adult indications, in addition to the current 200 mg every 3 weeks dosing regimen.
The approval was based on pharmacokinetic modeling and exposure-response analyses that compared the predicted exposure of 400 mg of pembrolizumab every 6 weeks to observed exposures of pembrolizumab in patients who received pembrolizumab at 2 mg/kg every 3 weeks, 200 mg every 3 weeks, and 10 mg/kg administered every 2 weeks. The pharmacokinetic modeling was supported by additional exposure/response analyses across the pembrolizumab development program, as well as an interim analysis of pharmacokinetics and overall response rate in a cohort of patients enrolled in the KEYNOTE-555 trial.
Cohort B of KEYNOTE-555 was an international, single-arm, multicenter study that enrolled 101 patients with advanced or metastatic melanoma who had not received prior programmed cell death protein 1, programmed cell death ligand 1, or CTLA-4 inhibitors (other than CTLA-4 inhibitors in the adjuvant setting). The overall response rate was 39% (95% confidence interval = 24%–55%) in the first 44 patients enrolled in KEYNOTE-555.
For additional safety and efficacy information as well as recommended dosing regimens, view the full prescribing information for pembrolizumab.
This new dosing regimen is approved under accelerated approval based on pharmacokinetic data, the relationship of exposure to efficacy, and the relationship of exposure to safety. Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial or trials.