Brentuximab Vedotin Combined with ABVD or AVD for Patients with Newly Diagnosed Advanced Stage Hodgkin Lymphoma: Long Term Outcomes

Background: The ABVD regimen containing doxorubicin, bleomycin, vinblastine, and dacarbazine is a common standard of care for the frontline treatment of advanced stage Hodgkin lymphoma (Santoro 1987; Duggan 2003) and is curative for the majority of patients; however, up to 30% of patients require a secondary therapy. Hodgkin Reed-Sternberg cells of classical HL (cHL) typically express CD30. In a pivotal phase 2 trial brentuximab vedotin (A, ADCETRIS®), comprised of an anti-CD30 monoclonal antibody conjugated by a protease-cleavable linker to a microtubule-disrupting agent, monomethyl auristatin E (MMAE) induced an objective response rate (ORR) of 75% and complete response rate (CR) of 34% in highly treatment-refractory patients with cHL (Younes 2012).

Methods: We conducted a phase 1, open-label, multicenter study to evaluate the safety and efficacy of A when administered in combination with standard therapy (ABVD) or the same regimen without bleomycin (AVD) (Younes 2013). Adult patients with newly diagnosed advanced stage (II bulky, II B, III or IV; 80% stage III or IV) received doses of 0.6, 0.9, or 1.2 mg/kg A with standard doses of ABVD or 1.2 mg/kg with AVD, depending on cohort assignment on Days 1 and 15 of each 28-day cycle for up to 6 cycles of therapy. Previously we reported that among patients assessable for response 95% of patients given ABVD+A achieved a CR, as did 96% of patients given AVD+A. None of 26 patients given AVD+A but 11 of 25 (44%) given ABVD+A experienced pulmonary toxicity, including 2 deaths, establishing that A cannot be safely combined with bleomycin. In this current study we provide the long term survival and safety data on patients enrolled in the phase 1 trial.

Results: In total 51 patients were assigned to either ABVD+A (n=25) or AVD+A (n=26). 1 patient who withdrew from the trial during the first cycle of ABVD+A is excluded from this analysis and 1 patient who received 3 cycles of ABVD+A, then withdrew, then received 3 cycles of ABVD alone and 2 patients who died during treatment (pulmonary toxicity) are included (total n=50). Median follow-up from diagnosis for the 24 patients treated with ABVD+A is 41 months (range 9-51 months) and for the 26 patients treated with AVD+A, 31 months (range 9-35 months). All 26 patients treated with AVD+A have been followed longer than the longest time to relapse (7 months). 45 patients remain in first CR and 5 treatment failures have occurred: 4 in the ABVD+A cohort (2 toxic deaths; 2 relapses (9 and 23 months from diagnosis)) and 1 after AVD+A (7 months from diagnosis). 3y-failure-free survival (3y-FFS) is 83% and 96% for ABVD+A and AVD+A, respectively, and 3y-overall survival (3y-OS), is 92% and 100%. No additional toxic deaths have occurred in follow-up.

Conclusions: These updated outcomes reflecting the impact of adding brentuximab vedotin (1.2 mg/kg) to standard doses of AVD for classical Hodgkin lymphoma, demonstrating 96% 3y-FFS and 100% 3y-OS with no major unexpected toxicity, strongly support the current large international trial comparing AVD-A (AVD+1.2mg/kg brentuximab vedotin) to standard ABVD (ECHELON-1, clinicaltrials.gov NCT01712490), which may identify a new, less toxic gold standard treatment for advanced stage classical Hodgkin lymphoma.