Nivolumab in Relapsed or Refractory Primary CNS Lymphoma: Multicenter, Retrospective Study.

Purpose: Given that 40~50% of primary central nervous system lymphoma (PCNSL) tissues exhibit aberrancy on 9p24.1, immune-checkpoint inhibitors (ICI) may work for the disease.

Materials and methods: To define the role of ICIs in PCNSL, we carried out a nationwide retrospect analysis for 22 patients who had been treated with nivolumab monotherapy for relapsed or refractory PCNSL.

Results: The median age at diagnosis was 66, and male: female ratio was 1:1. Patients received nivolumab after a median of 3 lines (range, 2 - 6) of therapy and at the median age of 67 (range, 37 - 82). Eleven patients (50%) were refractory to the last treatment prior to nivolumab. With a median follow-up duration of 22.3 months (95% CI, 13.1 - 31.5), nine patients (41%) had an objective response (6 complete responses, 3 partial responses), and the median duration of response was 20.9 months (95% CI, 1.7 - 40.0). The median progression-free survival and overall survival were 2.1 months (95% CI, 0.2 - 4.0) and 18.9 months (95% CI, 5.0 - 32.8), respectively. Nivolumab was generally well-tolerated as no patients required dose reduction and only 2 patients required delay of treatment.

Conclusion: Our study suggests that nivolumab can be a reasonable option with the durable response for RR PCNSL.