Day 30 SUVmax Predicts Progression in Lymphoma Patients Achieving PR/SD After CAR T-cell Therapy
About 70% of patients with large B-cell lymphoma (LBCL) treated with axicabtagene ciloleucel (axi-cel) who achieve a partial response (PR) or a stable disease (SD) on day 30 (D30) PET-CT scan progress, but predictive factors of progression are unknown. This a retrospective study of patients with LBCL treated with axi-cel at MD Anderson Cancer Center between 01/2018 and 02/2021. Among 50 patients with D30 PR/SD, 13 (26%) converted to complete response (CR). Among 95 patients with D30 CR, 72 (76%) remained in CR. On univariate analysis, the only day -5 characteristic associated with conversion from D30 PR/SD to subsequent CR was a higher platelet count (p=0.05). The only D30 factor associated with conversion from D30 PR/SD to subsequent CR was lower D30 SUVmax (p<0.001), and all patients with and D30 SUVmax ≥10 progressed. After a median follow-up of 12 months, no significant difference in median progression-free survival was observed when comparing patients who converted from D30 PR/SD to subsequent CR to those who had been in CR since D30 (p=0.19). Novel predictive and prognostic markers based on tissue biopsy and non-invasive diagnostic assays are needed to more effectively identify these patients and characterize the biology of their residual disease.