Tislelizumab for Relapsed/Refractory Classical Hodgkin Lymphoma: 3-Year Follow-up and Correlative Biomarker Analysis

PURPOSE: Tislelizumab is an anti–programmed cell death protein 1 (anti–PD-1) monoclonal antibody specifically designed to minimize binding to Fcγ receptors (FcγR). PATIENTS AND METHODS: Here, we present the extended 3-year follow-up of a phase II study of tislelizumab in 70 patients with relapsed/refractory classical Hodgkin lymphoma (cHL) who failed or were ineligible for autologous stem cell transplantation. RESULTS: With a median follow-up of 33.8 months, the overall response rate by the independent review committee was 87.1%, and the complete response (CR) rate was 67.1%. Responses were durable as shown by a median duration of response of 31.3 months, and median progression-free survival (PFS) of 31.5 months. The 3-year PFS and overall survival rates were 40.8% and 84.8%, respectively. Treatment-related adverse events (TRAEs) of any grade occurred in 97.1% of patients; the grade ≥3 TRAE rate was low (31.4%), and only 8.6% of patients experienced adverse events leading to treatment discontinuation. Correlative biomarker analysis showed that FcγRΙ-expressing macrophages had no observed impact on either the CR rate or PFS achieved with tislelizumab, which may be potentially related to its engineered Fc region. CONCLUSIONS: With extended follow-up, tislelizumab yielded long-term benefits and demonstrated a favorable safety profile for patients with relapsed/refractory cHL. This trial was registered at clinicaltrials.gov as NCT03209973.