FDG-PET/CT is a powerful tool to evaluate response to chimeric antigen receptor T-cell therapy in Diffuse Large B-Cell Lymphoma (DLBCL)

Ziel/Aim Chimeric antigen receptor (CAR) T-cell therapy has dramatically shifted the landscape of treatment for lymphoid malignancies, especially DLBCL. However, there continue to be significant limitations of this therapy, such as incomplete or nonsustained responses. This study evaluated the use of FDG-PET/CT for response assessment of CAR T-cell therapy in DLBCL.

Methodik/Methods 14 patients (4 f, 10 m) with DLBCL (56.5 ± 17.8 years) underwent FDG PET/CT prior (day 6.5 ± 2.4) and after (day 29.5 ± 4.3) CAR T-cell therapy between 08/19 and 08/20. Data were interpreted according to Lugano classification and compared to clinical follow up (6.5 ± 3.7 months).

Ergebnisse/Results One of 14 patients had to be excluded because of CAR T-cell engraftment failure. In the remaining 13 patients complete metabolic response (CMR) was observed in 9 (69.2 %) patients, therefrom one patient (7.7 %) relapsed after one month and one patient (7.7 %) died because of non-lymphoma reasons. One patient (7.7 %) was classified partial metabolic response (PMR) with remaining Deauville 5 score. However, due to clinically persistent complete remission (CR) for five months, a potential tumor flare reaction due to immune response was assumed. One patient (7.7 %) showed no metabolic response/stable disease (noMR/SD), two patients (15.4 %) showed progressive disease (PD). Respectively, 9 of 13 patients (69.2 %) were still in complete remission at time of analysis.

Schlussfolgerungen/Conclusions In our cohort, CAR T-cell therapy was successful in more than two thirds of treated DLBCL-patients. FDG-PET/CT performed one month after therapy allows an accurate assessment of response to CAR T-cell therapy (Sensitivity 75.0 %, Specificity 88.9 %). However on the one hand, in a minority of patients early relapses despite initial CMR may occur. On the other hand, tumor flare may falsely suggest only PMR due to persistent immune activity.

Publication History

Article published online:
08 April 2021