Ibrutinib before Apheresis May Improve Tisagenlecleucel Manufacturing in Relapsed/Refractory Adult Diffuse Large B-Cell Lymphoma: Initial Results from a Phase 1b Study

Background: Tisagenlecleucel (tisa-cel), an autologous anti-CD19 chimeric antigen receptor (CAR)-T cell therapy, has demonstrated durable responses and a manageable safety profile in adult patients (pts) with relapsed/refractory diffuse large B-cell lymphoma (r/r DLBCL). It has previously been suggested that prior therapy with ibrutinib, a Bruton's tyrosine kinase (BTK) inhibitor, may improve tisa-cel manufacturing, in vivo cellular kinetics, and antitumor efficacy (Fraietta et al. Blood. 2016). Moreover, since BTK signaling is involved in direct pro-inflammatory polarization of macrophages, as well as indirectly by T cells, it is hypothesized that ibrutinib may mitigate CAR-T cell-related toxicities such as cytokine release syndrome (CRS) and neurological events (NE). We report the initial results from a Phase Ib, multicenter, open-label trial evaluating the safety and tolerability of tisa-cel in combination with ibrutinib in adult pts with r/r DLBCL. Methods: Adult pts with r/r DLBCL who received >2 prior lines of systemic therapy, including pts who progressed after or were ineligible for autologous stem cell transplant, were enrolled. The study design has 2 nonrandomized arms. In Arm 1, pts received ibrutinib 560 mg/d for ~4 weeks prior to leukapheresis; in Arm 2, pts were exposed to ibrutinib after leukapheresis. In both arms, ibrutinib was continued throughout lymphodepleting chemotherapy, tisa-cel infusion, and post infusion for up to 24 months. Lymphodepleting chemotherapy, ending at least 2 days before tisa-cel infusion, was either fludarabine (25 mg/m2) and cyclophosphamide (250 mg/m2) daily for 3 days or bendamustine (90 mg/m2) daily for 2 days. Pts received a single infusion of tisa-cel (target dose: 0.6-6.0×108 viable CAR+ T cells). Primary endpoints are incidence and severity of adverse events and ibrutinib dose interruptions/modifications. Secondary endpoints include best overall response (BOR) by Lugano criteria and cellular kinetics of tisa-cel. Results: As of June 9, 2020, 10 pts have been treated and observed through at least the Day 28 assessment: 4 in Arm 1 and 6 in Arm 2. Median age was 59 (range, 32-67) in Arm 1 and 64 (range, 58-76) in Arm 2. Median number of prior therapies was 3.5 (range, 2-5) in Arm 1 and 2 (range, 2-3) in Arm 2. Three of 10 pts (Arm 1, n=1; Arm 2, n=2) had an activated B-cell-like subtype of DLBCL. Six of 10 pts (Arm 1, n=1; Arm 2, n=5) had grade 1 CRS (by Lee scale) and 1 pt had NE (Arm 2, grade 1 by ASTCT crite