Prognostic value of early imaging following CAR T-cell therapy in DLBCL.

Abstract

e19559 Background: Chimeric antigen receptor T-cell (CART) therapies lead to durable disease control in patients (pts) with relapsed/refractory (R/R) Diffuse Large B-cell Lymphoma (DLBCL). We assessed the prognostic value of response on first staging scan, and whether pts with progression of disease (PD) convert to a response on second scan. Methods: We conducted a retrospective analysis of pts with R/R DLBCL treated with CART at our institute. Baseline characteristics were assessed at apheresis. We included staging scans (CT, PET-CT and MRI) that occurred up to 6 months (mos) after CART infusion. Responses were determined via the Lugano 2014 criteria. Overall survival (OS) was calculated from first scan to last follow-up. Kaplan Meier method and Cox model were used to correlate first scan result with OS. Results: Of the 118 pts who received CART, 111 pts had evaluable staging scans (7 passed prior to first scan). Of the 111 pts, median age was 61 years (range, 23-84), and median number of prior therapies was 3 (range, 1-7). 61 pts received tisagenlecleucel, and 50 pts received axicabtagene ciloleucel. 22% of pts had MYC rearrangement by FISH. The majority of pts were stage 3/4 (91%), with an IPI score ≥2 (82%). 32%, 66% and 2% of pts had a CT, PET-CT or MRI as their first scan respectively. After a median follow-up of 16.2 mos, median OS from first scan was not reached (NR) (95% CI, 17-NR). 37%, 5%, 32%, 25% of pts had PD, SD, PR, and CR on first scan respectively. Median time to first scan was 59 days (range, 13-115). Median OS for pts who had PD was 3 mos (95% CI 2-8), and the median OS for those who attained SD, PR or CR was NR (95% CI NR-NR). Accounting for statistically important factors on multivariate analysis, PD on first scan was an independent predictor of OS (p<.001, HR 10.1 (95% CI 4.7-22)). We observed no evidence that pts with PD on first scan convert to a response on second scan without intervention. 26 of 41 pts who had PD did not start new treatment, 17 passed without follow-up scan, 1 is in follow-up, and 8 continued to show PD on subsequent scans. Conclusions: PD on first staging scan is a strong prognostic marker for survival for pts with R/R DLBCL who receive CART. There is no evidence to suggest conversion to a response will occur for patients who have PD. Performing staging scans at an earlier time-point has value, allowing for earlier treatment changes and goals of care conversations in this pt population.[Table: see text]