Treatment of relapsed/refractory mature T/NK-cell lymphomas with tislelizumab resulted in modest efficacy, with some patients achieving long-term remission, according to the results of a phase 2 study presented at the 2022 ASCO Annual Meeting.
Building on the prior success of tislelizumab among patients with relapsed/refractory classical Hodgkin lymphoma and solid tumors, the aim of this study was to evaluate the safety and efficacy of tislelizumab among patients with T/NK-cell lymphomas.
The open-label, single-arm, phase 2 study treated 77 patients with tislelizumab in 3 different cohorts: cohort 1 included 22 patients with relapsed/refractory extranodal disease; cohort 2 included 44 patients with mature T-cell lymphomas; and cohort 3 included 11 patients with cutaneous T-cell lymphomas (CTCL). The primary endpoint was investigator-assessed objective response rate (ORR) and secondary endpoints included duration of response (DOR), complete response (CR) rate, and survival.
At baseline, the majority of patients in the entire study population had advanced disease at 76.6%, refractory disease was present among 51.9%, and 49.4% had at least 3 prior lines of systemic therapy.
Patients in cohort 3 derived the greatest benefit from tislelizumab, with an ORR of 45.5%, including a CR of 9.1%. The median DOR was 11.3 months. The median PFS was 16.8 months and the median OS was not yet reached.
The ORR for cohort 1 was 31.8%, with a CR rate of 18.2% and a median DOR not yet reached. The median PFS and OS were 2.7 and 8.8 months, respectively. The ORR was lowest in cohort 2 at 20.5%, which included a CR rate of 9.1% and a median DOR of 8.2 months. The median PFS and OS were 2.7 and 13.3 months, respectively.
Within cohort 2, patients with peripheral T-cell lymphoma not otherwise specified (n=21) demonstrated the highest response at 23.8% with a CR rate of 14.3%.
The most common grade 3 or higher adverse events included anemia, pneumonia, and neutropenia. Immune-related adverse events of any grade developed in 28.6% of patients, with the most common being hypothyroidism, hyperglycemia, and rash. There were no treatment-related deaths.
The authors concluded that “tislelizumab was well tolerated, achieving modest efficacy in relapsed/refractory mature T/NK-cell neoplasms, with some long-lasting remissions, particularly in CTCL.” They added that “future studies are warranted to determine the biologic features associated with response.”
Disclosures: This study was supported by BeiGene USA, Inc.
Bachy E, Savage KJ, Huang H, et al. Tislelizumab, a PD-1 inhibitor for relapsed/refractory mature T/NK-cell neoplasms: results from a phase 2 study. Presented at ASCO 2022; June 3-7, 2022. Abstract 7552.