ZUMA-19: A Phase 1/2 Multicenter Study of Lenzilumab Use With Axicabtagene Ciloleucel (Axi-Cel) in Patients (Pts) With Relapsed or Refractory Large B Cell Lymphoma (R/R LBCL)

Background: Axi-cel is an autologous anti-CD19 chimeric antigen receptor (CAR) T cell therapy approved for pts with R/R LBCL with ≥ 2 prior systemic therapies. With a median follow-up of 27.1 months in ZUMA-1, the objective response rate (ORR) with axi-cel was 83% (58% complete response rate) in pts with refractory LBCL. Grade ≥ 3 cytokine release syndrome (CRS) and neurologic events (NEs) occurred in 11% and 32% of pts, respectively (Locke FL, et al. LancetOncol. 2019). Although CRS can be ameliorated with use of the anti-IL-6 receptor antibody tocilizumab, NEs may be unaffected or worsened by tocilizumab (Gust J, et al. Cancer Discov. 2017; Lee DW, et al. Blood. 2014; Santomasso BD, et al. Cancer Discov. 2018; Locke FL, et al. ASH 2017. #1547). Identification of mitigation strategies for NEs is complicated by a significant association between CAR T cell expansion and both ORR and Grade ≥ 3 NEs, suggesting a correlation between efficacy and adverse events (AEs; Neelapu SS, et al. N EnglJ Med. 2017). ZUMA-1 Cohort 4 suggested that earlier utilization of systemic corticosteroids for broad immune system suppression in pts with mild NEs and low-grade CRS may reduce the incidence of Grade ≥ 2 NEs without significant impact on efficacy (Topp MS, et al. ASH 2019. #243). However, this reactive approach has not fully abrogated NEs; as such, proactive strategies to further improve safety management with CAR T cell therapy without negatively impacting efficacy are needed.

Upon tumor challenge, CAR T cells produce granulocyte-macrophage colony-stimulating factor (GM-CSF; Giavridis T, et al. Nat Med. 2018), which acts to promote myeloid activation, expansion, and cytokine production (Spath S, et al. Immunity. 2017). GM-CSF was among the cytokines significantly associated with Grade ≥ 3 NEs in ZUMA-1 (Neelapu SS, et al. N Engl J Med. 2017). Notably, peak GM-CSF levels occurred before those of most other cytokines, and no direct association was observed between GMCSF levels and ORR (Rossi JM, et al. EMA Workshop, 2016). These findings suggest that GM-CSF may initiate inflammatory events that cause NEs and that GM-CSF inhibition has the potential to improve the safety of CAR T cells, without impacting efficacy. GM-CSF depletion with lenzilumab, a humanized monoclonal antibody that neutralizes GM-CSF, prevented CRS and NEs in preclinical models of CAR T cell toxicity (Sterner RM, et al. Blood2019). The Phase 1/2 ZUMA19 study is evaluating sequenced therapy with lenzilumab and axi-cel to prevent axi-cel-related CRS and NEs in pts with R/R LBCL.

Methods: Eligible pts are adults (≥ 18 y) with LBCL who relapsed after ≥ 2 systemic lines of therapy or are chemorefractory - defined as i) a best response of progressive disease (PD) or stable disease (SD) to ≥ 4 cycles of first-line systemic therapy (SD duration ≤ 6 months); or ii) a best response of PD or SD after ≥ 2 cycles of the most recent second-or-later line of systemic therapy. Prior therapy must have included an anti-CD20 monoclonal antibody and an anthracycline-containing regimen. Pts will undergo leukapheresis and may receive optional corticosteroid bridging therapy. Pts will then receive lymphodepleting chemotherapy on Days ‒3 to ‒5 followed by Day 0 administration of lenzilumab and, 6 hours later, a single infusion of axi-cel (target dose, 2 × 10⁶ CAR T cells/kg). Phase 1 will initially enroll pts in 2 dose-escalation cohorts; each will receive a single infusion of lenzilumab. Safety data will be reviewed after 3 and 6 (if needed) pts in each cohort have been followed for 28 days. The recommended Phase 2 dose (RP2D) of lenzilumab will be based on the dose-limiting toxicity rate (phase 1 primary endpoint), and, if necessary, translational assessment of GM-CSF axis suppression.

Phase 2 will assume a Simon 2-stage design. The primary endpoint for phase 2 is the incidence of Grade ≥ 2 NEs within 28 days of axi-cel administration. Efficacy, safety (including CRS and NEs), and blood levels of CAR T cells and cytokines (including GM-CSF) will be evaluated as secondary endpoints. An interim analysis will be performed when 14 subjects have received the RP2D in Phase 1 or 2 and are followed for ≥ 28 days after axi-cel infusion. If futility criteria are not met, enrollment will continue. Primary analysis will be performed after 30 pts are treated with RP2D of lenzilumab and have ≥ 6 months of follow up. ZUMA-19 is open and actively recruiting pts.