Alemtuzumab-Containing Allogeneic Hematopoietic Cell Transplant (HCT) for Relapsed Lymphomas: Prognostic Factors and Outcome.
Authors: Kenkre Vaishalee P. , Horowitz Sarah , Smith Sonali M. , Artz Andrew , Cohen Kenneth S. , Godley Lucy A , Kline Justin , Stock Wendy , Besien Koen van 
Published: October 2019

Abstract
Abstract 2247
Poster Board II-224
The role of allogeneic HCT for relapsed lymphomas remains imprecisely defined. Most pts considered for alloHCT are heavily pretreated and many have failed a prior autologous HCT. At The University of Chicago, 69 lymphoma pts (median age 54; range, 24-70) underwent allogeneic HCT after alemtuzumab-containing reduced intensity conditioning (RIC) regimens between 11/01 and 6/09. Ten had Hodgkin lymphoma (HL), 23 low-grade B-cell NHL (LGL), 17 intermediate-grade B-cell NHL (IGL), 9 mantle cell lymphoma (MCL), and 10 T-cell NHL (TCL). 25 pts (36%) had refractory disease and 17 pts (25%) had elevated LDH. Pre-HCT PET scans were performed in 48 pts and 31 (65%) were PET positive. Performance status (PS) was 0 for 45 pts (70%) and 1 for 18 pts (28%). 19 pts (27%) had failed a prior autologous transplant, and 4 pts had failed a prior allogeneic transplant. 31 pts (45%) had unrelated and 38 (55%) related donors. Conditioning regimens along with alemtuzumab included: fludarabine/melphalan (n = 40), clofarabine/melphalan (n = 20), fludarabine/busulfan (n = 5), and thiotepa/busulfan/cyclophosphamide (n = 4). GVHD prophylaxis consisted of single agent tacrolimus in all patients. With a median follow-up for survivors of 22 mos (range 2-94 mos), 2 yr overall survival (OS) is 53% (95%CI, 40-66). Progression-free survival (PFS) is 46% (95%CI, 34-58) at 1 yr and 38% (95%CI, 28-50) at 2 yrs. 11 pts had grade II-IV aGVHD and transplant-related mortality (TRM) was 20% at 1 yr. Disease responsiveness to salvage chemotherapy prior to transplant (as determined by CT scan) was highly predictive of PFS (p = 0.03). Pts with chemo-sensitive disease had a 2 yr PFS of 44% (95%CI, 28-60), those with chemo-refractory disease 30% (95% CI, 10-50). 2 yr PFS was 52% (95%CI, 30-74%) for LGL, 48% (95%CI, 12-84) for MCL, 28% (95%CI, 6-50) for IGL, 30% (95%CI, 0-60) for HL, and 34% (95%CI, 6-66) for TCL. Patient age, pre-transplant LDH, PS (0 vs 1), prior auto, donor type, and conditioning regimen did not correlate with outcome. Interestingly, a positive vs negative pre-HCT PET also did not correlate with outcome (p = 0.21). 23 pts (33%) relapsed. 13 of those have died, 2 are alive with disease, and 8 are in a durable subsequent remission lasting a median of 46 mos (range 8-69) after further chemotherapy (n=6) or DLI (n=2). Durable subsequent remissions were more common in those with late relapses (>6 mos after transplant) (Fig 1). Conclusion: Chemosensitivity by conventional CT scans remains the most important predictor of outcome. In contrast to other reports, neither the pre-HCT PET nor LDH correlate with outcome. Patients relapsing > 6 mos after alloHCT can re-enter durable remissions with chemotherapy alone. This suggests a favorable interaction between a persisting donor graft and salvage chemotherapy.

Disclosures:
Off Label Use: off-label use of clofarabine and alemtuzumab. Kline:Genzyme corporation: Membership on an entity's Board of Directors or advisory committees. Stock:Genzyme: Research Funding.