Charlotte B Wagner, Ken Boucher, Adrienne Nedved, Ivana N Micallef, Sanjal Desai, Haris Hatic, Gaurav Goyal, Erin Zacholski, Amanda Fegley, Audrey M Sigmund, David A Bond, Courtney Samuels, Manali K Kamdar, Sheeba Ba Aqeel, Pallawi Torka, Kira MacDougall, Azra Borogovac, Sridevi Rajeeve, Suchitra Sundaram, Kalub Fedak, Dipenkumar Modi, Elizabeth Travers, Sabarish Ayyappan, Nitin Chilakamarri, Elizabeth A Brem, Daniel A Ermann, Lindsey A Fitzgerald, Boyu Hu, Deborah M Stephens, Harsh Shah

Sixteen cycles of Brentuximab vedotin (BV) after autologous stem cell transplant (ASCT) in high-risk relapsed/refractory classical Hodgkin lymphoma (r/r cHL) demonstrated an improved 2-year progression free survival (PFS) over placebo. However, most patients are unable to complete all 16 cycles at full dose due to toxicity. This retrospective, multicenter study investigated the effect of cumulative maintenance BV dose on 2-year PFS. Data were collected from patients who received at least one cycle of BV maintenance after ASCT with one of the following high-risk features: primary refractory disease (PRD), extra-nodal disease (END), or relapse < 12 months (RL<12) from the end of frontline therapy. Cohort 1 had patients with > 75% of the planned total cumulative dose, cohort 2 with 51 - 75% of dose, and cohort 3 with ≤ 50% of dose. The primary outcome was 2-year PFS. A total of 118 patients were included. Fifty percent had PRD, 29% had RL<12, and 39% had END. Forty-four percent of patients had prior exposure to BV and 65% were in complete remission (CR) before ASCT. Only 14% of patients received the full planned BV dose. Sixty-one percent of patients discontinued maintenance early and majority of those (72%) were due to toxicity. The 2-year PFS for the entire population was 80.7%. The 2-year PFS was 89.2% for cohort 1 (n=39), 86.2% for cohort 2 (n=33), and 77.9% for cohort 3 (n=46) (p = 0.70). These data are reassuring for patients who require dose reductions or discontinuation to manage toxicity.