Safety and efficacy of tisagenlecleucel plus pembrolizumab in patients with r/r DLBCL: phase 1b PORTIA study results

Tisagenlecleucel demonstrated high response rates and a manageable safety profile in adults with relapsed/refractory diffuse large B-cell lymphoma (r/r DLBCL) in the JULIET trial. However, lack of response and chimeric antigen receptor (CAR) T-cell exhaustion were observed in patients with programmed cell death protein 1 (PD-1) overexpression. Hence, pembrolizumab, a PD-1 inhibitor, was hypothesized to improve efficacy and cellular expansion of CAR T-cells in vivo. Here, we report the final analysis of the PORTIA trial in adult patients with r/r DLBCL who had & GE;2 prior lines of therapy and had an Eastern Cooperative Oncology Group performance status of & LE;1. Patients received 1 tisagenlecleucel infusion on day 1. Pembrolizumab (200 mg) was given every 21 days, for up to 6 doses. Three cohorts initiated pembrolizumab on days 15 (n = 4), 8 (n = 4), or -1 (n = 4). Safety, efficacy, cellular kinetics, and biomarker analyses were included. Tisagenlecleucel plus pembrolizumab was feasible and showed a manageable safety profile, without dose-limiting toxicities. Emerging efficacy with tisagenlecleucel was observed when pembrolizumab was given the day before tisagenlecleucel; however, the limited patient sample and short follow-up do not allow for definitive conclusions. Adding pembrolizumab to tisagenlecleucel did not augment the cellular expansion of tisagenlecleucel but delayed peak expansion if given the day before tisagenlecleucel (NCT03630159).

Automated summary

In the PORTIA trial, it was feasible to add pembrolizumab to tisagenlecleucel for adult patients with r/r DLBCL who had& GE;2 prior lines of therapy and had an Eastern Cooperative Oncology Group performance status of& LE;1. The combination showed a manageable safety profile and had potential efficacy benefits when pembrolizumab was given the day before tisagenlecleucel.