A real-world analysis of PD1 blockade from the Rete Ematologica Pugliese (REP) in patients with relapse/refractory Hodgkin's lymphoma.

Checkpoint inhibitors have significantly changed the prognosis of patients with relapsing refractory classical Hodgkin's lymphoma (cHL), demonstrating excellent results in heavily pretreated patients. However, there is still limited data on the real-world experience with PD-1 inhibitors in cHL. Within the context of the Apulian hematological network (Rete Ematologica Pugliese, REP), we performed a retrospective, multicenter analysis of 66 patients with relapsing refractory cHL who had received PD-1 inhibitors in the non-trial setting. Forty-three patients (65%) were treated with nivolumab and 23 (35%) with pembrolizumab. Thirty-one (47%) and 8 (12%) patients underwent autologous or allogeneic stem cell transplantation prior to checkpoint inhibitor therapy, respectively. The median number of lines of treatment attempted prior to PD-1 inhibitor therapy was 4 (range, 3 to 7). All patients had received brentuximab vedotin prior to checkpoint inhibitor therapy. The overall response rate to PD-1 inhibitors therapy was 70% (47% complete remission (CR) and 23% partial remission (PR)). Twenty-four immune-related adverse events (19 (80%) grades 1-2; 5 (20%) grades 3-4) were documented (4 gastrointestinal, 4 hepatic, 6 fever, 4 hematological, 3 dermatological, 3 allergic rhinitis). Toxicity resolved in all patients, and there were no deaths attributed to checkpoint inhibitor therapy. After a median follow-up of 26 months (range 3-72 months), 54 patients (82%) are alive, and 12 (18%) died. The cause of death was attributed to disease progression in 9 patients and sepsis in 3 patients. After PD-1 inhibitor therapy, 22 patients (33%) relapsed or progressed. The overall survival and progression-free survival at 5 years were 65% and 54%, respectively. This study confirms the efficacy and tolerability of PD-1 inhibitor therapy in relapsed refractory cHL in a real-world setting, demonstrating similar clinical outcomes and toxicity profiles compared to clinical studies.