Objective: The interplay between systemic inflammation, activity of lymphoid organs and lymphoma activity in CD19-targeting chimeric antigen receptor (CAR)-T-cell immunotherapy, and its significance for response and toxicity, is not well defined.
Methods: Using serial 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT), metabolic parameters of lymphoma and lymphoid organs were analyzed in ten patients receiving Tisagenlecleucel (an autologous CD19 CAR-T cell product) for relapsed or refractory diffuse large B-cell lymphoma. The prevalence and severity of toxicity (e.g., neurotoxicity) were noted.
Results: Achieving remission required early metabolic response (P = 0.0476). Early suppression of metabolic activity of lymphoid organs (spleen, P = 0.0368; lymph nodes, P = 0.0470) was associated with poor outcome. Lymphoma metabolic activity was significantly higher in patients with neurotoxicity (P = 0.0489).
Conclusions: Early metabolic changes in lymphoma lesions and off-target lymphoid organs parallel medium-term response to CAR-T-cell therapy. PET can identify patients at risk for severe toxicity.
Keywords: CAR-T-cell therapy; Lymphoid organs; Outcome; Positron emission tomography; Toxicity.