Response-adapted therapy (tx) with nivolumab plus brentuximab vedotin (nivo + BV) without autologous hematopoietic cell transplantation (auto-HCT) in children, adolescents, and young adults (CAYA) with low-risk relapsed/refractory (R/R) classic Hodgkin lymphoma (cHL): CheckMate 744.

Abstract

7515 Background: Outcomes are poor for patients (pts) with cHL who develop R/R disease after first-line (1L) chemotherapy ± radiotherapy (RT). Salvage tx that attain high event-free survival (EFS) rates and minimize late toxicity by omitting high-dose chemotherapy (HDCT)/auto-HCT are needed. CheckMate 744 (NCT02927769) is the first multicenter phase 2 study evaluating a risk-stratified, response-adapted salvage tx with nivo + BV in CAYA with R/R cHL. In the standard-risk cohort, complete molecular response (CMR) rate before consolidation with HDCT/auto-HCT was 94% (Harker-Murray et al. Blood 2022). With highly active salvage tx, pts in low-risk cohort could achieve high EFS without HDCT/auto-HCT; we report data from this cohort. Methods: Pts were aged 5–30 y and had ≤ 3 cycles (C) of 1L anthracycline-based systemic tx. Risk stratification was described in Harker-Murray et al. Pts received 4C of nivo + BV induction. Pts with CMR received additional 2C nivo + BV before involved-site radiation therapy (ISRT) consolidation (dose, 30–30.6 Gy). Pts with suboptimal response received 2C BV + bendamustine intensification; pts with CMR proceeded to ISRT consolidation. Primary endpoints: CMR rate (Lugano 2014) any time before ISRT and 3-y EFS rate, both per blinded independent central review (BICR). For CMR and overall response rate (ORR), a 90% confidence interval (CI) was used per statistical plan. Results: Among 28 pts treated with nivo + BV, median (range) age was 17 (6–27) y; 64% of pts were aged < 18 y. Most (64%) pts had stage II disease at relapse; 82% had relapse ≥ 12 mo after 1L tx, 2 pts had prior RT. Median (range) follow-up was 31.9 (2.2–55.3) mo. CMR, ORR, 3-y EFS and PFS rates are shown in Table. Median duration of response was not reached; 87% of pts had sustained response at 36 mo’ follow-up. Efficacy outcomes were comparable in the pediatric population (CMR per BICR before ISRT, 88.9%; 3-y EFS rate, 78.3%). During induction, 22 (78.6%) pts had treatment-related adverse events (TRAEs; grade 3/4, 25.0% pts; hematologic, < 10% pts; immune-mediated, 21.4%). Serious AEs leading to discontinuation included rash, pyrexia, and acute kidney injury (1 pt each). Conclusions: The findings demonstrate that most CAYA with low-risk R/R cHL can be salvaged with chemoimmunotherapy with a favorable toxicity profile, and do not require HDCT/auto-HCT. Clinical trial information: NCT02927769 . [Table: see text]