Earlier Steroid Use with Axicabtagene Ciloleucel (Axi-Cel) in Patients with Relapsed/Refractory Large B Cell Lymphoma (R/R LBCL)

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Background Axi-cel is an autologous anti-CD19 chimeric antigen receptor (CAR) T cell therapy approved for the treatment (Tx) of patients (pts) with R/R LBCL with ≥ 2 prior systemic therapies. In Cohorts 1+2 (C1+2) of the ZUMA-1 study, Grade ≥ 3 cytokine release syndrome (CRS) and neurologic events (NEs) occurred in 11% and 32% of pts, respectively (Locke FL et al, Lancet Oncol 2019). A nonrandomized safety expansion cohort (Cohort 4 [C4]) evaluated the impact of earlier steroid use on CRS and NE rates. Here we present the primary analysis of ZUMA-1 C4 with a greater number of pts and longer follow-up (F/U). Methods Eligible pts were leukapheresed, could receive optional bridging chemotherapy (not allowed in C1+2), and received conditioning chemotherapy before axi-cel infusion at a targeted 2 × 106 anti-CD19 CAR T cells/kg. C4 pts received early steroid intervention at Grade 1 NE and at Grade 1 CRS after 3 days of supportive care. Primary endpoints were incidence and severity of CRS and NEs. ORR and CAR T cell levels were compared across quartiles of tumor burden (TB). Results As of May 6, 2019, 41 pts had received axi-cel, with a median F/U of 8.7 mo. Pts who received bridging therapy prior to axi-cel (68%) all had evidence of disease after bridging, documented by a new baseline PET/CT scan. The median age was 61 y (range, 19 – 77 y; 32% ≥ 65 y). The majority of pts (63%) had DLBCL; 49% had an ECOG 1; 70% had disease stage III/IV; 68% were refractory to ≥ 2nd-line therapy; 63% had ≥ 3 prior lines of therapy; and 20% had relapsed after ASCT. C4 pts had a lower median TB by sum of product diameters (SPD; C4: 2100 mm2; C1+2: 3723 mm2) and lower pre-Tx serum LDH level than C1+2 pts. A greater proportion of C4 pts received steroids and tocilizumab vs C1+2 (73% and 76% vs 27% and 43%). Fewer C4 pts experienced Grade ≥ 3 CRS (2%) and NE (17%) than C1+2 pts. The ORR in C4 was 73% with a CR rate of 51%. Response was ongoing in C4 54% of pts with ≥ 6 mo F/U vs the 44% ongoing response rate at the primary analysis of C1+2 (also ≥ 6 mo F/U). Although most pts in C4 had lower SPDs than those in C1+2, responses were comparable when evaluated by TB. Median DOR was 8.9 mo, consistent with that observed for C1+2 (8.1 mo; Locke, AACR 2017; Figure). Median PFS was 11.7 mo; median OS was not reached. Peak CAR T cell levels were 42 cells/µL blood in C1+2 vs 59 cells/µL in C4. C1+2 had a median CAR AUC of 462 cells/µL × days vs 512 cells/µL in C4. CAR T cell expansion was comparable between cohorts when adjusted by TB. Levels of key NE-associated biomarkers including ferritin (pre- and post-Tx) and IL-2 (post-Tx) appeared lower in C4 than in C1+2. Conclusions Earlier steroid use may reduce the rates of CAR T cell Tx-related CRS and NEs without affecting efficacy. Conclusions are limited by the nonrandomized study design and differences in population sizes and baseline characteristics between cohorts. Optimizing AE management is important to improve the benefit–risk profile of CAR T cell therapy.