New first-line treatment strategies for classical Hodgkin lymphoma (cHL) have not improved overall survival (OS) compared with doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD). Five-year data from ECHELON-1 (NCT01712490) supported long-term progression-free survival (PFS) with brentuximab vedotin, doxorubicin, vinblastine, and dacarbazine (A+AVD) in patients (pts) with previously untreated stage III/IV cHL vs ABVD, with a manageable long-term safety profile. We report an OS analysis from ECHELON-1 after a median of 6 years of follow-up (data cutoff June 1, 2021). Randomized pts (1:1) received ≤6 cycles of A+AVD (n=664) or ABVD (n=670) on days 1 and 15, every 28 days. The key secondary end point was OS (event-driven, type-1 error controlled) in the intent-to-treat population. Analysis of OS in prespecified subgroups was exploratory and not adjusted for multiplicity. PFS per investigator was reported for long-term follow-up. Deaths during follow-up, including reported causes of death per investigator, were summarized. We observed 39 OS events in the A+AVD arm vs 64 with ABVD, favoring A+AVD (hazard ratio [HR] 0.59; 95% confidence interval [CI] 0.40–0.88; p=0.009; median follow-up 73 months; Figure). OS was examined in prespecified subgroups; in a multivariable analysis adjusting for baseline demographic and disease factors, OS benefit was preserved (HR 0.53; 95% CI 0.34–0.83). PFS favored A+AVD (HR 0.68; 95% CI 0.53–0.86), consistent with prior reports. Subsequent therapy use was less frequent with A+AVD vs ABVD (135 [20%] vs 157 [24%]) including fewer autologous (44 [7%] vs 59 [9%]) and allogeneic stem cell transplants (4 [<1%] vs 12 [2%]) while use of radiation was similar (55 [8%] vs 58 [9%]), suggesting that the OS benefit was not due to undertreatment of pts in the ABVD arm. Fewer second malignancies (23 vs 32) and fewer deaths related to cHL or treatment complications (32 vs 45) or to second malignancies (1 vs 11) were reported with A+AVD vs ABVD, respectively; treatment-related deaths were comparable (8 vs 7). While fertility was not formally assessed, a total of 191 pregnancies were reported among pts and their partners (A+AVD 113; ABVD 78). More pts had peripheral neuropathy with A+AVD (443 [67%]) vs ABVD (286 [43%]), but most improved or resolved at last follow-up (379 [86%] vs 249 [87%]). To conclude, A+AVD significantly reduced risk of death vs ABVD by 41%. The long-term safety profile was manageable, consistent with prior reports.