CD19-targeting chimeric antigen receptor (CAR)-T cell therapy has shown great efficacy in patients with relapsed/refractory non-Hodgkin lymphoma (NHL) but has been associated with serious adverse effects, such as cytokine release syndrome (CRS). It has been speculated that NHL baseline disease burden might affect clinical outcome and CRS, but this has not been explored in detail in any previous study. Metabolic tumor volume (MTV) and total lesion glycolysis (TLG), as measured by fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET-CT), are quantitative indicators of baseline tumor burden. Using FDG PET-CT, we calculated baseline and post-CAR-T cell therapy MTV and TLG in 19 patients with NHL. The median MTV was 72 cm3 (range, .02 to 1137.7 cm3), and the median TLG was 555.9 (range, .011 to 8990.3). After a median follow-up of 5 months (range, 1 to 12 months), the best overall response rate was 79.0%. The baseline MTV and TLG did not differ significantly between patients with response and those without response (P = .62 and .95, respectively). On Cox regression analysis, baseline MTV and TLG were not significantly associated with overall survival (P = .67 and .45, respectively). Patients with mild and moderate CRS (grade 0 to 2) had significantly lower MTV and TLG than those with severe CRS (grade 3 to 4) (P = .008 for MTV comparison, P = .011 for TLG comparison). Using FDG PET-CT, we also demonstrated that CAR-T cell therapy in patients with NHL was associated with pseudoprogression and local immune activation. Our data indicate that patients with higher baseline disease burden have more severe CRS, and that CAR-T cell therapy is associated with lymphoma pseudoprogression and local immune activation.
Keywords: Chimeric antigen receptor T cell; Diffuse large B cell lymphoma; Metabolic tumor burden; Positron emission tomography/computed tomography; Pseudoprogression.
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