FDA Approves Pembrolizumab for PMBCL

Today, the US Food and Drug Administration (FDA) approved pembrolizumab (Keytruda, Merck) for the treatment of adult and pediatric patients with refractory primary mediastinal large B-cell lymphoma (PMBCL) or who have relapsed after 2 or more previous lines of therapy.

Data collected from 53 patients with relapsed or refractory PMBCL participating in a multicenter, open-label, single-arm trial, KEYNOTE‑170 (NCT02576990) served as the basis for the approval. Subjects were administered 200 mg of pembrolizumab 200 until unacceptable toxicity or documented disease progression or for up to 24 months for patients who did not progress.

Forty-five percent (95% CI: 32, 60) was the overall response rate, which included 11% complete responses and 34% partial responses. Within the follow-up period (median 9.7 months), the median duration of response was not reached. The median time to first objective response was 2.8 months.

For patients with PMBCL who require urgent cytoreductive therapy, pembrolizumab is not recommended for treatment.

Musculoskeletal pain, upper respiratory tract infection, pyrexia, fatigue, cough, dyspnea, diarrhea, abdominal pain, nausea, arrhythmia, and headache included the most common adverse reactions, which occurred in ≥10% of patients with PMBCL treated in KEYNOTE-170. In 8% and 15% of patients, respectively, pembrolizumab was discontinued or interrupted due to adverse reactions. An adverse reaction requiring systemic corticosteroid therapy occurred in 25% of patients.

For the treatment of adults with PMBCL, the recommended pembrolizumab dose is 200 mg every 3 weeks. In pediatric patients, the recommended dose is 2 mg/kg (up to a maximum of 200 mg) every 3 weeks.