Long-Term Outcomes of Nivolumab Therapy in Patients with Relapsed/Refractory Classic Hodgkin’s Lymphoma after High-Dose Chemotherapy with Autologous Hematopoietic Stem Cell Transplantation in Real Clinical Practice

Aim. To assess prognostic factors and to analyze the outcomes of nivolumab therapy in patients with relapsed/re-fractory classic Hodgkin's lymphoma (cHL) after autologous hematopoietic stem cell transplantation (auto-HSCT). Materials & Methods. The retrospective analysis included 42 patients treated with nivolumab 3 mg/kg after auto-HSCT in the period from 2016 to 2020. The response to nivolumab therapy was assessed every three months by whole-body PET/CT based on LYRIC criteria. Toxicity profile was assessed by establishing adverse events (AE) based on NCI CTCAE 4.03 criteria. Results. The study included 42 patients with relapsed/re-fractory cHL: 21 (50 %) men and 21 (50 %) women. The median age was 32.5 years (range 22-43 years). At diagnosis the following cHL stages were identified: stage II in 14 pts (33.3 %), stage III in 12 pts (28.6 %), and stage IV in 16 pts (38.1 %). Primary chemoresistance after the first-line therapy was observed in 26 pts (61.9 %) and early relapse in 4 pts (9.52 %). The median follow-up was 38 months, 3-year overall survival was 97 % (95% confidence interval, 95% CI, 83.2-99.6 %), 3-year progression-free survival (PFS) was 34.8 % (95% CI 20.3-49.9 %; median 12.9 months). Objective response was reported in 69 % of patients, complete response (CR) in 33.3 %, partial response in 35.7 %, stable disease in 7.1 %, indeterminate response in 14.3 %, and progression in 9.5 % of patients. The analysis of factors affecting PFS revealed significant differences in patients who reached CR after 6 nivolumab cycles: 3-year PFS 56.2 % (95% CI 24.4-79.1 %) vs. 25.2 % (95% CI 10.46-43.1 %) in patients who did not reach CR (p = 0.054). If extranodal lesions were identified at nivolumab therapy onset, PFS was 29 % (95% CI 7.8-37.5 %) vs. 68 % (95% CI 35.9-86.8 %) in their absence (p = 0.0079). The overall rate of AEs on nivolumab therapy was 92.9 %, severe AEs of grade 3-4 were observed in 19.1 % of patients. Conclusion. Nivolumab shows high efficacy in the treatment of patients with relapsed/refractory cHL after the failure of auto-HSCT and considerably improves prognosis compared with historical control. The efficacy of nivolumab is independent of brentuximab vedotin use and duration of prior therapy. Throughout the follow-up period the toxicity level of nivolumab was acceptable and controlled. Clinical factors that affect prognosis for patients on immunotherapy were identified.