LBA7000 Background: We hypothesized that therapy with the novel BrECADD regimen (brentuximab vedotin, etoposide, cyclophosphamide, doxorubicin, dacarbazine, dexamethasone) guided by positron emission tomography after two cycles (PET2) could improve the treatment of advanced-stage classical Hodgkin lymphoma (AS-cHL). The HD21 trial aimed at demonstrating superiority over the intensified BEACOPP regimen (bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, prednisone) in terms of treatment-related morbidity (TRMB) and non-inferiority (NI) in terms of progression-free survival (PFS). This is the first report of the final confirmative analysis of the HD21 trial. Methods: HD21 is an international, open-label, randomized phase III trial including AS-cHL patients 18-60 years at diagnosis. Patients were randomized to receive individualized 4 or 6 cycles of either BEACOPP or BrECADD guided by PET2 results. The co-primary endpoints included TRMB and PFS, which had been successfully established recently. Testing for superiority was planned with mature follow-up of four years. An adjusted alpha level of 0.047 was required to cross the efficacy boundary for superiority. The trial was conducted in accordance with ICH-GCP (NCT02661503) and supported by a research grant from Takeda Oncology. Results: The ITT (intention-to-treat) cohort for the efficacy analysis consisted of 1482 patients, of which 742 were randomized to receive BrECADD and 740 to BEACOPP. Median age was 31.1 years (range 18 to 60), 44% were female. PET2 was negative in 424 (57.5%) and 426 (58.2%) patients for BrECADD or eBEACOPP, respectively, and these were scheduled for 4 treatment cycles. With median follow-up of 48 months, 4y-PFS was 94.3% for BrECADD (95%-CI 92.6-96.1), and 90.9% for BEACOPP (95%-CI 88.7-93.1). The hazard ratio was 0.66 [95% CI 0.45-0.97], p=0.035). PFS benefit of BrECADD was driven by a reduction in early treatment failures, i.e., primary progression within 3 months (5 vs. 15) or early relapse between months 3 and 12 (11 vs. 23) and observed across all investigated subgroups. PET2-negative patients in the BrECADD group showed a 4-year PFS of 96.5%. 4-year OS was 98.5% for BrECADD and 98.2% for BEACOPP. Analyses of gonadal function demonstrated significantly higher follicle stimulating hormone recovery rates after one year in both men (67% vs. 24%) and women (89% vs. 68%) with higher birth-rates in the BrECADD group (n=60 vs. n=43). Conclusions: BrECADD is significantly more effective than BEACOPP and is associated with an unprecedentedly high 4-year PFS, reducing the risk of progression, relapse or death by a third. Together with an abbreviated treatment duration of only 3 months for the majority of patients and a favorable tolerability, treatment with PET2-individualized BrECADD sets a new benchmark for the treatment of adult patients with AS-cHL. Clinical trial information: NCT02661503 .

Tolerability and efficacy of BrECADD versus BEACOPP in advanced stage classical Hodgkin lymphoma: GHSG HD21, a randomized study.