Prophylactic corticosteroid use in patients receiving axicabtagene ciloleucel for large B-cell lymphoma.

ZUMA-1 (NCT02348216) examined the safety and efficacy of axicabtagene ciloleucel (axi-cel), an autologous CD19-directed chimaeric antigen receptor (CAR)-T cell therapy, in refractory large B-cell lymphoma. To reduce treatment-related toxicity, several exploratory safety management cohorts were added to ZUMA-1. Specifically, cohort 6 investigated management of cytokine release syndrome (CRS) and neurologic events (NEs) with prophylactic corticosteroids and earlier corticosteroid and tocilizumab intervention. CRS and NE incidence and severity were primary end-points. Following leukapheresis, patients could receive optional bridging therapy per investigator discretion. All patients received conditioning chemotherapy (days -5 through -3), 2 × 106  CAR-T cells/kg (day 0) and once-daily oral dexamethasone [10 mg, day 0 (before axi-cel) through day 2]. Forty patients received axi-cel. CRS occurred in 80% of patients (all grade ≤2). Any grade and grade 3 or higher NEs occurred in 58% and 13% of patients respectively. Sixty-eight per cent of patients did not experience CRS or NEs within 72 h of axi-cel. With a median follow-up of 8·9 months, objective and complete response rates were 95% and 80% respectively. Overall, prophylactic corticosteroids and earlier corticosteroid and/or tocilizumab intervention resulted in no grade 3 or higher CRS, a low rate of grade 3 or higher NEs and high response rates in this study population.

Armored CAR T-cells: utilizing cytokines and pro-inflammatory ligands to enhance CAR T-cell anti-tumour efficacy.

Chimaeric antigen receptor (CAR) T-cells are T-cells that have been genetically modified to express an artificial construct consisting of a synthetic T-cell receptor (TCR) targeted to a predetermined antigen expressed on a tumour. Coupling the T-cell receptor to a CD3ζ signalling domain paved the way for first generation CAR T-cells that were efficacious against cluster of differentiation (CD)19-expressing B-cell malignancies. Optimization with additional signalling domains such as CD28 or 4-1BB in addition to CD3ζ provided T-cell activation signal 2 and further improved the efficacy and persistence of these second generation CAR T-cells. Third generation CAR T-cells which utilize two tandem costimulatory domains have also been reported. In this review, we discuss a different approach to optimization of CAR T-cells. Through additional genetic modifications, these resultant armored CAR T-cells are typically modified second generation CAR T-cells that have been further optimized to inducibly or constitutively secrete active cytokines or express ligands that further armor CAR T-cells to improve efficacy and persistence. The choice of the 'armor' agent is based on knowledge of the tumour microenvironment and the roles of other elements of the innate and adaptive immune system. Although there are several variants of armored CAR T-cells under investigation, here we focus on three unique approaches using interleukin-12 (IL-12), CD40L and 4-1BBL. These agents have been shown to further enhance CAR T-cell efficacy and persistence in the face of a hostile tumour microenvironment via different mechanisms.