FDA Approves Pembrolizumab for Relapsed/Refractory PMBCL

Pembrolizumab was granted an accelerated approval by the U.S. Food and Drug Administration (FDA) for the treatment of adult and pediatric patients with refractory primary mediastinal large B-cell lymphoma (PMBCL), or patients whose disease relapsed after receiving two or more prior lines of therapy.

The agency based its decision on results from the multicenter, open-label, single-arm KEYNOTE-170 trial, which enrolled 53 patients with relapsed/ refractory PMBCL who received pembrolizumab 200 mg intravenously every three weeks until unacceptable toxicity or documented disease progression.

After a median follow-up of 9.7 months (range not reported), the overall response rate was 45 percent, including a complete response rate of 11 percent and a partial response rate of 34 percent. The median time to response was 2.8 months (range = 2.1-8.5 months), and the median duration of response was not reached (range = 1.1 to >19.2 months) within the follow-up period.

The most common adverse events (AEs; occurring in ≥10% of patients) included musculoskeletal pain (30%), upper respiratory–tract infection (28%), pyrexia (28%), fatigue (23%), cough (26%), dyspnea (21%), diarrhea (13%), abdominal pain (13%), nausea (11%), arrhythmia (11%), and headache (11%). Grade 3/4 AEs included dyspnea (11%), arrhythmia (4%), fatigue (2%), cough (2%), and diarrhea (2%).

The approval letter noted that pembrolizumab is not recommended for treatment of patients with PMBCL who require urgent cytoreductive therapy, and the accelerated approval for pembrolizumab in this setting is contingent on the results of a confirmatory trial.

Source: FDA news release, June 13, 2018.