Impact of time to relapse and response to salvage therapy on post autologous stem cell transplant outcomes in relapsed or refractory diffuse large B-cell lymphoma.
Authors: Aung M. Tun, Yucai Wang, Seth Maliske, Umar Farooq, Ivana N. M. Micallef, David James Inwards, Luis F. Porrata, Stephen M. Ansell, Allison Claire Rosenthal, Mohamed Kharfan-Dabaja, Brian K. Link, Jose Caetano Villasboas, Jonas Paludo, James Robert Cerhan, Thomas Matthew Habermann, Thomas E. Witzig, Grzegorz S. Nowakowski, Patrick B. Johnston
Journal: Journal of Clinical Oncology (2021)

e19501 Background: The current standard of care for patients with relapsed or refractory (RR) diffuse large B-cell lymphoma (DLBCL) following frontline immunochemotherapy (IC) is salvage therapy, followed by high-dose chemotherapy and autologous stem cell transplant (ASCT) rescue in patients responding to salvage therapy. Time to first relapse (or refractory status) and response to salvage therapy in patients with RR DLBCL may reflect the chemosensitivity of the underlying disease. The aim of this study is to determine whether these factors impact post-ASCT outcomes. Methods: Patients with DLBCL that relapsed after R-CHOP or R-CHOP-like frontline therapy who underwent salvage therapy and ASCT at Mayo Clinic or University of Iowa between 07/2000 and 4/2020 were identified from institutional lymphoma and transplant databases. Clinical characteristics, treatment information, and outcome data were abstracted. Progression-free survival (PFS) and overall survival (OS) from the time of ASCT were analyzed using Kaplan-Meier method and Cox proportional hazards models. Results: A total of 437 patients with RR DLBCL who underwent salvage therapy and ASCT were identified. 280 (64%) were male. Median time from initial diagnosis to 1 st relapse/salvage was 1.0 years (range 0.1-16.4). A median of 1 line (range 1-3) of salvage therapy was required. Response prior to ASCT was complete response (CR) in 211 (48%), partial response in 199 (46%), stable disease in 24 (5%), and unknown in 3 (1%) patients. Median age at ASCT was 61 years (range 19-78), and median follow up after ASCT was 8.0 years (95% CI 7.2-8.7). Median PFS and OS was 2.7 (95% CI 1.5-4.3) and 5.4 (4.2-7.4) years, respectively. Time to 1 st relapse/salvage (≤1 vs 1-2 vs &gt; 2 years) was not associated with PFS (median 0.8 vs 2.4 vs 4.9 years, p = 0.170) but was associated with OS (2.4 vs 7.4 vs 6.8 years, p = 0.013). Patients who required &gt; 1 line of salvage therapy had significantly inferior PFS (median 0.3 vs 4.5 years, p &lt; 0.001) and OS (0.9 vs 7.4 years, p &lt; 0.001). In addition, patients who failed to achieve a CR prior to ASCT had significantly worse PFS (median 0.8 vs 5.3 years, p &lt; 0.001) and OS (2.7 vs 9.2 years, p &lt; 0.001). In multivariate Cox regression models adjusted for age and sex, time to 1 st relapse/salvage was not associated with PFS (p = 0.313) or OS (p = 0.081); however, lines of salvage and response prior to ASCT remain significantly prognostic for PFS ( &gt; 1 line of salvage: HR 2.14, 95% CI 1.59-2.87, p &lt; 0.001; non-CR: HR 1.61, 95% CI 1.26-2.05, p &lt; 0.001) and OS ( &gt; 1 line of salvage: HR 2.25, 95% CI 1.66-3.05, p &lt; 0.001; non-CR: HR 1.63, 95% CI 1.26-2.12, p &lt; 0.001). Conclusions: In patients with RR DLBCL following frontline IC, requiring more than 1 line of salvage therapy and failure to achieve CR are strong independent risk factors for poor PFS and OS after ASCT. Novel therapies such as CAR-T cell therapy should be studied in this population.