(18)F-FDG PET/CT of off-target lymphoid organs in CD19-targeting chimeric antigen receptor T-cell therapy for relapsed or refractory diffuse large B-cell lymphoma


Ann Nucl Med. 2020 Nov 11. doi: 10.1007/s12149-020-01544-w. Online ahead of print.


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.