Efficacy Of Radioimmunotherapy-Based Conditioning With High-Dose Chemotherapy And Autologous Stem Cell Transplantation For Transformed Lymphoma

8556 Background: Transformed non-Hodgkin lymphoma (TF NHL) has a poor prognosis with median survival of 7-20 months. Studies have suggested the benefit of HDC. The series by Eide showed 47%, 5yr OS in 47 pts treated with HDC and ASCT (Br J Hem 2011). Our multicenter experience with RIT plus HDC (Yttrium 90 ibritumomab tiuxetan plus BEAM; carmustine, etoposide, cytarabine, melphalan "ZBEAM") demonstrated the safety and efficacy of the regimen in diffuse large cell lymphoma (DLCL). Therefore, the regimen was explored in other subtypes of NHL. Herein we report the outcome of 57 pts with TF NHL treated with ZBEAM conditioning and ASCT at three centers (City of Hope USA n=20, VUMC the Netherlands n=31, Chaim Sheba Med Center, Israel n=6.) between 2003- 2011. Methods: Histological confirmation of transformation was defined as dx of DLCL in pts with either a prior history or concomitant dx of follicular NHL. Results: Median age at ASCT was 59.6 yrs (range 41-69). Median number of prior regimens 2 (range 1-6), all pts received rituximab in at least one regimen. Disease status at ASCT: 1st CR 29, 1stPR 7,1st rel 9, IF 5, 2nd CR 5, 2nd rel 1, >3CR 1. Median time from TF NHL dx to ASCT was 7.7 mo (range 2.8-116). Pts engrafted white cells at median of 12 days (range 8-33). Non relapse mortality was 3.5%. There were two second malignancies: 1 MDS and 1 SCC Skin. Median f/u for living pts was 29 mo (range 7-100). Two year PFS was 69.67% (95%CI 59.39 - 77.83) and OS 90.29% (95% CI: 79.63 - 95.52). On univariate analysis, number of prior regimens, time from TF NHL dx to ASCT and history of marrow involvement were not significant for PFS and OS. Disease status at ASCT was significant for PFS in 1st CR vs relapse disease ( p=0.03) The relapsed pts had a significant increase in risk of relapse/progression or death post ASCT compared to the 1CR patients. [HR = 2.9, (95% CI: 1.07 - 7.9)]. Conclusions: ZBEAM conditioning with ASCT is an active treatment for pts with TF NHL, and is particularly efficacious as consolidation for pts in 1st CR.