Outcomes of Salvage Stem Cell Transplantation in Hodgkin Lymphoma in a Single Institution in the Modern Era

Background: Though overall Hodgkin lymphoma (HL) carries one of the best outcomes among lymphoma, about 40% of patients relapse and/or fail to respond to initial therapy. Out of those about half can be cured with salvage therapy followed by high dose therapy and autologous stem cell transplantation (ASCT) while eligible patients who fail and/or relapse after HDT-ASCT are offered nonmyeloablative stem cell transplantation. Achieving a negative PET response prior to ASCT correlate with superior outcome in HL regardless of their clinical presentation. More recently novel therapies have emerged in the field from brentuximab vedotin approved in r/r setting in HL as well as checkpoint inhibitors currently in trials with very promising results. This study analyzed a cohort of HL pts transplanted at our institution over the last 5 years to identify potential new patterns in the evolving landscape of HL.

Methods: We performed a retrospective analysis of r/r HL pts referred to our center for salvage therapy at our institution between 2009 and 2014 using the Blood and Bone marrow transplant database at HUMC.

Results: A total of 66 patients with r/r HL transplanted at HUMC were identified. Baseline characteristics were as follows: male 57%, female 43%, median age 36.8y (range 16-66), Frontline therapy was ABVD in all but one pt who received Gemzar, Vinorelbine, Doxil; and 27% pts received consolidation w/ radiation. Median time to relapse was 7mo (range 0.93-87mo), stage at first relapse I-0, II-33%, III-20%, IV-23%, NA 24%. The salvage regimen used was ICE in 54 pts, brentuximab vedotin in 8 pts and HCVAD in 4 pts. Involved field radiation was used in 10% at salvage prior to HDT-ASCT. Responses after first salvage were as follows: PET-CR 59%, CT-CR 5%, PR-14%, PD-12%, NA-10%. As per our practice, pts not in CR after first salvage continue to the next salvage until they reach a CR. Pts not in CR after 2 lines of salvage were considered for allogeneic stem transplantation (alloSCT). Conditioning regimen was BEAM prior to ASCT, reduced intensity (fludarabine-based) prior to alloSCT. Source of allo stem cells was: MRD in 7 pts, MUD in 3 pts, haploidentical donor in 2 pts. A total of 59 pts had ASCT, 6 pts had alloSCT as first transplant (primary refractory), while 6 pts underwent alloSCT for relapse after ASCT. Disease status post first transplant was as follows: PET-CR 76%, CT-CR 17%, PR-1%, PD-6%. All 6 alloSCT pts are alive in remission, while 13 out of 59 ASCT pts have relapsed, 7 relapses occurred within the first year, 3 within the second year post ASCT. Out of 6pts with alloSCT after ASCT relapse, 4 pts are alive in CR, one died from PD, one died from PTLD (in CR from HL). After a median follow up of 24.5 mo (3.7-70), the 3y PFS and OS are 73% and 95% respectively. For CR and PR after first salvage to SCT pts, median PFS and OS has not been reached. For SD/PD after first salvage therapy pts median PFS is 14.5mo, median OS 47mo. No significant difference in mPFS and mOS is seen in pts who received one vs more than one salvage therapy prior to ASCT or had radiation as part of frontline or salvage therapy.

Conclusion: We report on a consecutive series of high-risk r/rHL. Our results demonstrate an improved outcome compared to historical data. Pts requiring more than one salvage prior to SCT while having mPFS of only 14.5 mo, have prolonged survival at median 47 mo.

While the number is small, selected young pts with high risk relapsed HL may benefit from alloSCT. Strategy of requiring CR prior to SCT, and alloSCT (instead of ASCT) in pts requiring more than 2 consecutive salvage regimens, availability of novel agents, diminishing use of RT may have contributed to observed improved outcomes.