Transplant-Free Approach in Relapsed Hodgkin Lymphoma in Children, Adolescents, and Young Adults: A Nonrandomized Clinical Trial.

Importance: Retrieval strategies for children, adolescents, and young adults with relapsed classic Hodgkin lymphoma (cHL) aim to maintain efficacy while minimizing long-term toxic effects. Children, adolescents, and young adults with low-risk, relapsed cHL may benefit from replacing high-dose chemotherapy and autologous stem cell transplant with less intensive involved-site radiotherapy (ISRT).

Objective: To evaluate a risk-stratified, response-adapted, transplant-free approach for treatment of children, adolescents, and young adults with low-risk relapsed cHL with nivolumab plus brentuximab vedotin (BV) followed by BV plus bendamustine for patients with suboptimal response and ISRT (30.0 to 30.6 Gy).

Design, setting, and participants: CheckMate 744 (R1 cohort) was a phase 2, nonrandomized, single-arm study enrolling children, adolescents, and young adults aged 5 to 30 years with low-risk cHL between September 25, 2017, and December 16, 2020, across the US, Canada, and Europe. Data were analyzed from September 2017 to November 2022.

Exposures: Patients received 4 cycles of nivolumab plus BV induction; patients with complete metabolic response (CMR) received an additional 2 cycles of nivolumab plus BV while patients with suboptimal response received 2 cycles of BV plus bendamustine intensification. Patients with CMR after induction or intensification received ISRT consolidation.

Main outcomes and measures: Prespecified coprimary end points were CMR rate (Lugano 2014 classification) any time before ISRT and 3-year event-free survival (EFS) rate, per blinded independent central review (BICR).

Results: Of 28 included patients treated in the low-risk cohort, 18 (64%) were female, and the median (range) age was 17 (6-27) years. At a median (range) follow-up of 31.9 (2.2-55.3) months, CMR per BICR any time before ISRT was 93% (26 of 28; 90% CI, 79.2-98.7; objective response rate [ORR], 100%), and 23 of 28 (82%) achieved CMR per BICR after 4 cycles of nivolumab plus BV (ORR, 96.4%). Kaplan-Meier estimates of EFS and progression-free survival rates at 3 years were 87% (3 of 18; 90% CI, 69.5-94.7) and 95% (1 of 18; 90% CI, 76.7-99.0), respectively. During induction, 22 patients (79%) had treatment-related adverse events, including 7 with grade 3 or 4 adverse events, 2 with anemia, 1 with neutropenia, and 6 with immune-mediated adverse events. Serious adverse events leading to discontinuation occurred in 2 patients.

Conclusions and relevance: This nonrandomized clinical trial found that for children, adolescents, and young adults with low-risk, relapsed cHL, a transplant-free, risk-adapted, response-based approach with nivolumab plus BV and ISRT offered high CMR rates and high 3-year EFS rate, with a safety profile consistent with that of each agent used.

Trial registration: ClinicalTrials.gov Identifier: NCT02927769.