Brentuximab Vedotin Improves HCT-CI, CR Status, and Peri-Transplant Toxicity In Patients With Relapsed/Refractory Hodgkin Lymphoma Heading To RIC Allo-HCT

Background The prognosis of patients with Hodgkin lymphoma (HL) who relapse following autologous hematopoietic cell transplantation is poor. Although reduced intensity allogeneic hematopoietic cell transplantation (RIC allo-HCT) can induce durable remissions in some patients with relapsed/refractory HL, its use is limited by patient co-morbidities, lack of disease control prior to HCT, and transplant related morbidities/mortalities. Brentuximab vedotin (BV), a novel antibody-drug conjugate, has a 75% objective response rate in patients with relapsed/refractory HL (Younes 2012). We performed a retrospective analysis comparing patient characteristics prior to HCT and outcomes after HCT in relapsed/refractory HL patients who received BV and underwent RIC allo-HCT versus those who did not receive BV but underwent RIC allo-HCT. Methods Between Jan 2003 and July 2009 (Pre-BV era), we identified a consecutive case-series of 23 HL patients who underwent RIC allo-HCT with no prior BV exposure (no-BV group). From July 2009 to Dec 2012, we identified a consecutive case-series of 21 additional HL patients who received BV prior to RIC allo-HCT (BV group). Co-morbidities at the time of HCT were measured by the HCT-CI. The Bearman scale was used to capture toxicities associated with RIC allo-HCT. PFS and OS were calculated using Kaplan-Meier method. Results Baseline characteristics are listed in [Table 1][1]. All patients received fludarabine and melphalan conditioning regimens. Groups were similar in terms of age, stage, response to induction, number of prior therapies, donor type, cell source, and prior auto-HCT. Groups differed in terms of GVHD prophylaxis (institutional shift to tacro/siro from 2005), remission status, and co-morbidity index (HCT-CI) at the time of HCT. Patients in the BV group were more likely to be in complete remission (CR) at the time of transplant (p=0.04). The median HCT-CI was better in the BV group (0 vs. 2, p=0.003). Also the Bearman toxicity score during transplant showed fewer grade III-IV events in the BV patients (0 vs. 7, p=0.015). View this table: Table 1 The median follow-up for living patients in the no-BV group was 70.2 month and 23.3 months for the BV group (5 year lag for BV group). The 2-yr PFS for the no-BV group was 26.1% (95% CI: 21.5, 30.9) compared to 51.8% (95% CI: 38.5, 63.6) for the BV group, p=0.099. The 2-yr cumulative incidence of relapse/progression for no-BV was 56.5% (95% CI: 33.2, 74.4) compared to 28.9% (95% CI: 9.9, 51.4) for BV, p= 0.066. The 2-yr OS was 56.5% (95% CI: 44.3, 67) for no-BV compared to 66.6% (95% CI: 47.8, 80.0) for BV. Non-relapse mortality (NRM) at day 100 was 4.3% and 17.4% at 1 yr for the no-BV group. For the BV group NRM at day 100 was 0% and 11.8% at 1 yr. The rate of aGVHD and cGVHD were 56.5% and 78.3% for no-BV, and 33.3% and 76.2% for BV groups, respectively. Conclusion BV prior to RIC allo-HCT in relapsed HL leads to improvements in 1) HCT-CI 2) CR status at time of transplant, and 3) reduced peri-transplant toxicity. Disclosures: Chen: Seattle Genetics, Inc.: Consultancy, Research Funding, Speakers Bureau, Trave expenses Other. Siddiqi: Seattle Genetics: Speakers Bureau. [1]: #T1