Allogeneic hematopoietic cell transplantation (alloHCT) in diffuse large B-cell lymphoma (DLBCL) after nonmyeloablative (NMA) or reduced-intensity (RIC) conditioning: Long-term outcome in 116 patients.

Abstract

8561 Background: The role of alloHCT and conditioning intensity in DLBCL remains unclear. In this retrospective study, we determined their effectiveness in 116 patients (pts) with DLBCL (de novo, n=59, transformed, n=57) receiving alloHCT at our institution, between 1998-2011. Methods: Median age was 51years (range, 19-70); median prior therapies was 4 (range 2-12). Disease status at alloHCT was complete response (CR) (n=22), partial response (PR) (n=58), stable (SD) (n=25) or progressive disease (PD) (n=11). 41 (35%) pts had previous autografts. 74 (64%) pts received RIC of melphalan/fludarabine (Flu) or BEAM, and 42 (36%) received a NMA conditioning of Flu/cyclophosphamide or cisplatin/cytarabine/ Flu. Donor source was HLA-identical sibling (MRD) (65%), HLA-matched unrelated (MUD) (31%) or a 1-Ag mismatched donor (4%). Results: With median follow-up among survivors of 63 months (range 5-157), estimated 5-yr OS and PFS for the whole cohort was 41% and 34% respectively. On multivariate (MV) analysis, disease status was most significant predictor for OS, with chemo refractory disease (SD/PD) being associated with higher mortality rate (HR 3.7, 95% CI 1.6-8.6, p=0.002). Combined use of NMA conditioning and MRD was associated with significantly lower mortality rate (HR 0.4, 95% CI 1.6-8.6, p=0.005). OS was highest [69% (95% CI 49-82)} for pts in CR/PR after NMA with a MRD (n=29), and lowest [(12% (95% CI 3-29)] for SD/PD pts after RIC with a non MRD (n=32). Disease status was strongest predictor of PFS on MV analysis, with CR pts having improved PFS compared to SD/PD (5-year estimates of 58% and 13%, respectively (P<0.001). Pts in PR with early disease stage (< Stage 4) and negative PET at alloHCT had PFS comparable to pts in CR (56% at 5 yr HR=1.3, p=0.6), while all other PR pts had PFS comparable to SD/PD pts (PFS=20%, p 0.1). Conclusions: Our study shows disease status, donor type and conditioning intensity are predictors of outcomes after alloHCT in DLBCL. Pts with chemosensitive disease and receiving NMA, MRD had improved survival rates compared to RIC alloHCT. PR pts with low volume PR had similar outcomes to CR pts.