A multi‐center retrospective study of pembrolizumab in patients with relapsed or refractory extranodal nk/t‐cell lymphoma

Background: Extranodal natural killer T-cell lymphoma (ENKTL) is an aggressive malignancy with a dismal prognosis. PD-1 blockade with pembrolizumab has shown promising activity in relapsed/refractory (R/R) ENKTL in case series. Real-world data about the efficacy of pembrolizumab in R/R ENKTL patients are limited. Methods: We performed a multicenter retrospective study to evaluate pembrolizumab efficacy and safety in patients with R/R ENKTL from 10 academic centers in South Korea. Pembrolizumab 100 mg was administered intravenously every 3 weeks. Results: A total of 24 patients were enrolled. The median age was 67 years old (range, 36–87) and 29.2% of patients had an Eastern Cooperative Oncology Group (ECOG) performance status of 2 or greater. Pembrolizumab was administered as 2nd-, 3rd- and 4th or greater line chemotherapy in 9 (37.5%), 9 (37.5%), and 6 (25.0%) patients, respectively, and median 3 cycles (range 1–21) of pembrolizumab were given. In response evaluation, complete remission (CR) and partial response (PR) was achieved in 6 (25.0%) and 3 (12.5%), respectively. The median progression-free survival and overall survival were 2.0 months (95% CI, 0.9–3.0) and 8.0 months (95% CI, 0.0–22.4), respectively. Multivariate analysis indicated that ECOG PS was the only significant predictor of PFS after pembrolizumab treatment (hazard ratio, 5.33; 95% confidence interval, 1.09–26.1; P = .039) Overall, 14 (58.3%) patients experienced adverse events (AEs), with fatigue (n = 7, 29.1%) being the most common Eight patients (33.3%) developed G3-4 AEs, the most frequent of which was neutropenia (4,16.7%) Conclusion: Pembrolizumab could be a therapeutic approach for the control of R/R ENKTL. Keyword: Aggressive T-cell non-Hodgkin lymphoma No conflicts of interests pertinent to the abstract.