Pembrolizumab for the Treatment of Relapsed and Refractory Classical Hodgkin Lymphoma After Autologous Transplant and in Transplant-Naïve Patients.

Introduction: Checkpoint inhibitors demonstrated significant efficacy in relapsed/refractory Hodgkin's Lymphoma (R/R cHL) resulting in high responses and prolonged progression free survival in patients, who relapse after or are ineligible for autologous stem cell transplantation (auto-SCT). We aimed to assess the efficacy and toxicity of Pembrolizumab before auto-SCT and in transplant naïve patients and calculate survival outcomes.

Patients And Methods: Fifty-five patients with R/R cHL were included. Patients demographics, including age, sex, risk stratification, therapy received and details pertaining transplantation, were collected.

Results: Median age was 28 years (range, 16-62 years). The median follow-up was 15.3 months and the median number of previous treatments was 3 (1-10). The best objective response was 74.5% (CR 32.7%, SD 5.5%) with reasonable safety profile. Twenty-nine of the responding patients received subsequent auto-SCT and 9 allogeneic stem cell transplantation (allo-SCT), 6 are currently alive with ongoing response. At the time of analysis, 6 patients remained on Pembrolizumab and the rest discontinued. The main reason for discontinuation was disease progression (n-49). Twelve-months overall survival and progression free survival (PFS) was 92% (95% CI: 76%-95%) and 51% (95% CI, 39%-67%) respectively. Twelve-month PFS for patients, who achieved CR or PR or PD was 88% (95% CI: 07%-75%); PR 60% (95% CI: 21%-29%) and 5% (95% CI: 5%-0%). Though the number of patients who received auto-SCT after Pembrolizumab was small (n-15), 12 months overall survival and PFS 100% and PFS 92%. 11 patients (20%) deceased during the follow-up and none was regarded to be treatment-related.

Conclusion: Checkpoint inhibitors are effective in heavily pretreated cHL patients with reasonable survival outcomes. The results supporting the concept of auto and/or allo-SCT after checkpoint inhibitors use.