Is autologous transplant in relapsed DLBCL patients achieving only a PET+ PR appropriate in the CAR T-cell era?

ABSTRACT

For relapsed chemosensitive diffuse large B-cell lymphoma (DLBCL), consolidation with autologous hematopoietic cell transplantation (auto-HCT) is a standard option. With the approval of anti-CD19 chimeric antigen receptor T cells in 2017, the Center for International Blood and Marrow Transplant Research (CIBMTR) reported a 45% decrease in the number of auto-HCTs for DLBCL in the United States. Using the CIBMTR database, we identified 249 relapsed DLBCL patients undergoing auto-HCT from 2003 to 2013 with a positive positron emission tomography/computed tomography (PET/CT)+ partial response prior to transplant were identified. The study cohort was divided into 2 groups early chemoimmunotherapy failure (ECF), defined as patients with primary refractory disease (PRefD) or relapse within 12 months of diagnosis and late chemoimmunotherapy failure, defined as patients relapsing after ≥12 months. Primary outcome was overall survival (OS). Secondary outcomes included progression-free survival (PFS) and relapse. A total of 182 patients had ECF, whereas 67 did not. Among ECF cohort, 79% had PRefD. The adjusted 5-year probabilities for PFS and OS (ECF vs no ECF) were not different 41% vs 41% (P = .93) and 51% vs 63% (P = .09), respectively. On multivariate analysis, ECF patients had an increased risk for death (hazard ratio, 1.61; 95% confidence interval, 1.05-2.46; P = .03) but not for PFS or relapse. In conclusion, for relapsed chemosensitive DLBCL patients with residual PET/CT+ disease prior to auto-HCT, the adjusted 5-year PFS (41%) was comparable, irrespective of time to relapse. These data support ongoing application of auto-HCT in chemosensitive DLBCL.