Prognostic Impact of 18F-FDG PET/CT in Patients With Aggressive B-Cell Lymphoma Treated With Anti-CD19 Chimeric Antigen Receptor T Cells

Abstract

Purpose of the Report We aimed to evaluate the role of 18F-FDG PET/CT in predicting patient outcome following chimeric antigen receptor T (CAR T) cells infusion in aggressive B-cell lymphoma. Methods 18F-FDG PET/CT data before leukapheresis, before CAR T-cell infusion and 1 month (M1) after CAR T-cell infusion, from 72 patients were retrospectively analyzed. SUVmax, total lesion glycolysis (TLG), metabolic tumor volume (MTV), and parameters describing tumor kinetics were calculated for each 18F-FDG PET/CT performed. The aim was to evaluate the prognostic value of 18F-FDG PET/CT metabolic parameters for predicting progression-free survival (PFS) and overall survival (OS) following CAR T-cell therapy. Results Regarding PFS, ∆MTVpre-CAR and ∆TLGpre-CAR were found to be more discriminating compared with metabolic parameters at preinfusion. Median PFS in patients with a ∆MTVpre-CAR of less than 300% was 6.8 months (95% confidence interval [CI], 2.8 months to not reached) compared with 2.8 months (95% CI, 0.9–3.0 months) for those with a value of 300% or greater (P = 0.004). Likewise, median PFS in patients with ∆TLGpre-CAR of less than 420% was 6.8 months (95% CI, 2.8 months to not reached) compared with 2.7 months (95% CI, 1.3–3.0 months) for those with a value of 420% or greater (P = 0.0148). Regarding OS, metabolic parameters at M1 were strongly associated with subsequent outcome. SUVmax at M1 with a cutoff value of 14 was the most predictive parameter in multivariate analysis, outweighing other clinicobiological variables (P < 0.0001). Conclusions Disease metabolic volume kinetics before infusion of CAR T cells seems to be superior to initial tumor bulk itself for predicting PFS. For OS, SUVmax at M1 might adequately segregate patients with different prognosis.

Positron emission tomography-imaging assessment for guiding strategy in patients with relapsed/refractory large B-cell lymphoma receiving CAR T cells

“…Therefore, from our results, M1 evaluation seems the preferable slot of time for response assessment in these patients. In addition we have confirmed herein the strong prognostic value of the baseline metabolic tumor volume already reported by us and others 7,23,24 as a tool to identify early progressors. Indeed, the high-risk category with TMTV>80ml at baseline accounted for 70 patients among whom 41% progressed before the M1 evaluation and 11% were in stable or progressive response at M1.…”

Early FDG-PET response predicts CAR-T failure in large B-cell lymphoma

“…Baseline high-risk factors, including LDH and ECOG PS, 2,4,5,15 inform patient selection pre–CAR-T, but by the time patients have undergone treatment and have responded, an individual patient’s risk will have changed. On-treatment biomarkers, including imaging markers of response (eg, DS or disease metabolic volume kinetics 16 ), should be incorporated into a dynamic, postinfusion risk model.…”

Whole body FDG PET/MR for progression free and overall survival prediction in patients with relapsed/refractory large B-cell lymphomas undergoing CAR T-cell therapy

“…A lower tumor burden and/or lower tumor FDG uptake have been linked to better outcomes. An early metabolic response after treatment has also proved predictive of therapy success, assessed visually [ 13 , 16 ] or semi-quantitatively using SUV max [ 12 , 13 , 15 ]. In general, the studies performed are however small and mixed results have been reported in terms of which predictive metric to use.…”