Efficacy of immune checkpoint inhibitors in paediatric, adolescent and young adults with primary refractory or relapsed classical Hodgkin lymphoma: A national multicentre real-world study.

Classical Hodgkin lymphoma (cHL) is the most frequent lymphoma in children, adolescents and young adults (CAYA). Despite therapeutic advances, around 15% of patients relapse or have refractory (R/R) disease. Conventional salvage regimens remain effective but are associated with substantial long-term toxicity. Immune checkpoint inhibitors (CPIs), such as nivolumab and pembrolizumab, and the anti-CD30 antibody-drug conjugate brentuximab vedotin (BV) have recently demonstrated encouraging efficacy with improved safety. We conducted a retrospective, multicentre nationwide study to assess the real-world efficacy of CPI in CAYA patients (<18 years) with R/R cHL treated outside clinical trials in France between August 2015 and May 2023. Twenty-seven patients from 11 centres were included. Median age at CPI initiation was 16 years; 70% had advanced disease. Prior treatments included BV (44%), autologous stem cell transplantation (22%) and allogeneic transplantation (4%). Nivolumab was used in 89%, frequently combined with BV (67%). The overall response rate was 93%, with 63% achieving complete metabolic response. After a median follow-up of 28 months, 3-year progression-free survival and overall survival were 48% and 95%, respectively, and toxicities were manageable. These findings strongly support CPI as a highly effective and well-tolerated treatment option for the CAYA population with R/R cHL even in heavily pretreated patients.