FDA Approves Pembrolizumab for Treatment of Relapsed/Refractory PMBCL

The FDA has granted an accelerated approval to pembrolizumab (Keytruda) for the treatment of adult and pediatric patients with refractory primary mediastinal large B-cell lymphoma (PMBCL), or those who have relapsed after 2 or more prior lines of therapy.

The approval is granted based on the results of the multicenter, open-label, single-arm KEYNOTE‑170 trial (NCT02576990), which involved 53 patients with relapsed/refractory PMBCL. At a median follow-up of 9.7 months, the overall response rate was 45% (95% CI, 32-60), comprising a complete response rate of 11% and a partial response rate of 34%.

The median time to initial objective response was 2.8 months, and the median duration of response was not reached.

In KEYNOTE-170, all-grade adverse events (AEs) occurring in at least 10% of patients included musculoskeletal pain, upper respiratory tract infection, pyrexia, fatigue, cough, dyspnea, diarrhea, abdominal pain, nausea, arrhythmia, and headache.

Eight percent of patients discontinued treatment due to AEs and 15% experienced dose interruptions. Corticosteroid therapy was required for AEs in 25% of patients. Serious AEs were reported by 26% of patients.

The FDA noted in its approval statement that the agency does not recommend pembrolizumab for patients with PMBCL who require urgent cytoreductive therapy.

Pembrolizumab has existing approved indications in melanoma, lung cancer, head and neck cancer, cervical cancer, gastric cancer, Hodgkin lymphoma, urothelial carcinoma, and microsatellite instability—high solid tumors.