Outcomes of Patients with Refractory/Relapsed Diffuse Large B-Cell Lymphoma Who Progress After Autologous Stem Cell Transplantation in the Rituximab Era.
Authors: Nagle Sarah J. , Woo Kaitlin , Mick Rosemarie , Schuster Stephen J. , Nasta Sunita D. , Stadtmauer Edward A. , Svoboda Jakub 
Published: October 2019

Abstract
Abstract 2689
Salvage chemotherapy and autologous stem cell transplant (ASCT) remain the current standard of care for patients with diffuse large B-cell lymphoma (DLBCL) who have primary refractory disease or relapse after initial therapy. The addition of rituximab results in improved overall survival (OS) after first line treatment, but cure rates of salvage therapy and ASCT are inferior when compared to historical controls (Gisselbrecht et al, JCO 2010). In the pre-rituximab era, patients with DLBCL who progressed after ASCT had an extremely poor prognosis, with a median OS of 3 months from the time of progression (Vose et al, Blood 1992). There is a paucity of data regarding outcomes and clinical patterns following progression after ASCT in the rituximab era.
We conducted a retrospective analysis using our institutional database of DLBCL patients who underwent ASCT for primary refractory or relapsed disease. For those who progressed after ASCT, we evaluated OS defined as time from date of progression after ASCT to date of death from any cause or last follow-up. We also analyzed OS for various subgroups based on their clinical characteristics and post-progression therapy. The impact of post-progression therapy on outcome was assessed by calculating OS from the time of exposure to a particular treatment to date of death from any cause or last follow-up. Median OS was estimated by the Kaplan-Meier method and subgroup comparisons were performed using the log rank test.
We identified 215 patients with primary refractory or relapsed DLBCL who underwent ASCT between January 1, 2005 and December 31, 2011. All patients received rituximab as part of their first line treatment. Fifty-six patients (26% of total) were found to have progression after ASCT. Eight patients were excluded from the analysis because they were not re-biopsied at relapse (n=5) or they had indolent disease at relapse (n=3). Data on the remaining 48 patients (median age 57 years; range 20–74) were further analyzed. The median OS from progression after ASCT for the entire cohort was 10.7 months (95% CI: 6.8–18.0 months). Patients who progressed < 1 year from ASCT (n=39) had a significantly shorter OS than those who progressed ≥ 1 year from ASCT (n=9): 9.5 vs. 26.7 months (p=0.02). Patients with at least stable disease as first assessment after ASCT (n=29) had a significantly longer OS than those who progressed immediately after ASCT (n=19): 18 vs. 6 months (p=0.01). Patients who were exposed to at least one novel agent (lenalidomide, radioimmunotherapy, non-rituximab monoclonal antibodies or tyrosine kinase inhibitors) as part of their post-progression therapy after ASCT (n=20) had a median OS of 11.2 months from treatment initiation. In contrast, patients who were treated with conventional cytotoxic chemotherapy but not novel agents (n=20) had a median OS of 6.7 months. In particular, patients who underwent radioimmunotherapy at some point after progression post-ASCT (n=9) had a median OS of 17.5 months (95% CI: 2.6-n/a months) with one patient in complete response > 48 months after the treatment. Patients who underwent allogeneic stem cell transplant following progression after ASCT (n=6) had a median OS of only 7.1 months (95% CI: 0.8-n/a months).
In the rituximab era, the median OS of DLBCL patients who progress after ASCT appears improved when compared to historical controls, especially in those who progress > 1 year from ASCT. Patients with DLBCL progressing after ASCT should be considered for therapy with novel agents, which may result in long term survival.

Disclosures:
No relevant conflicts of interest to declare.