Diffuse Large B-Cell Lymphoma (DLBCL) Patients with Late Relapses Who Are Transplant-Eligible Have Excellent Outcomes and May Represent Unique Biology

• Published in: Blood 2021-11, Vol.138 (Supplement 1), p.2499-2499
• Main Authors: Ngu, Henry S., Hilton, Laura K, Rodrigo, Judith Anula, Villa, Diego, Gerrie, Alina S., Song, Kevin, Farinha, Pedro, Slack, Graham W., Savage, Kerry J., Scott, David W., Sehn, Laurie H.
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2021-149049

Introduction Approximately 30-40% of patients (pts) with DLBCL have refractory disease or relapse following R-CHOP. The majority of pts will experience disease progression or relapse early (within 1-2 years), although ~20% experience late relapse >24 months (m) from time of initial diagnosis. Salvage therapy followed by autologous stem cell transplantation (ASCT) has been standard therapy for transplant-eligible pts, regardless of timing of documented relapsed/refractory (rel/refr) disease. Recent studies exploring the use of CAR T-cell therapy in primary refractory and early relapsed pts is challenging this paradigm. However, pts with late relapses were omitted from these studies. Interestingly, emerging molecular data suggest tumors of pts with late relapses exhibit significant genetic diversity from the initial diagnostic tumor, and may in fact represent unique biology (Hilton et al, ICML 2021). We aimed to evaluate outcomes in transplant-eligible pts with rel/refr DLBCL according to timing of documented rel/refr disease in a population-based setting to further explore biological and treatment implications. Method We identified all pts within the BC Cancer Centre for Lymphoid Cancer Database, age 18 to 75y, diagnosed with biopsy-confirmed DLBCL treated with curative-intent R-CHOP-like immunochemotherapy between 2001-2020 with documented rel/refr disease. Only transplant-eligible pts treated with standard salvage immunochemotherapy with intention for hematopoeitic stem cell transolantation (HSCT) were included. Patients with incidental discordant bone marrow involvement with low grade B-cell lymphoma were included, but transformed pts and those with isolated central nervous system relapse were excluded. Pts were divided into three cohorts based on timing of documented rel/refr disease from time of initial diagnosis: (1) rel/refr < 12m; (2) relapse between 12 to 24 m; (3) late relapse >24 m. Overall survival (OS) was calculated from time of documented rel/refr disease and from the time of HSCT in pts undergoing SCT. Results 225 pts meeting the stated eligibily criteria were identified. Clinical characteristics at initial diagnosis were as follows: median age 58y (range 19-72y); 70% male; 46 % IPI score 3-5. Timing of rel/refr disease from initial diagnosis was: rel/refr 24m, n= 48, 21%. 92% of pts with late relapse had biopsy-proven relapsed DLBCL. Approximately 95% of pts received a platinum-based s