The anti-PD-L1 monoclonal antibody, sugemalimab, resulted in an objective response rate (ORR) of 44.9% among patients with relapsed/refractory extranodal natural killer (NK) cell or T-cell lymphoma (R/R ENKTL). The treatment was considered well tolerated with no unexpected toxicities, according to a report in the Journal of Clinical Oncology.
The multicenter, single-arm, phase 2 GEMSTONE-201 trial treated 80 adult patients with ENKTL with sugemalimab for up to 24 months. All patients had received at least 1 prior line of treatment and had an Eastern Cooperative Oncology Group performance status of 0 or 1. The primary endpoint was ORR, and secondary endpoints included complete response (CR) rate, duration of response (DOR), and safety.
At baseline, the median age was 48 and 36.3% of patients were female. There were 46.3% of patients who were refractory to treatment and 53.8% who had relapsed. There were 51.3% of patients who had 1 prior line of treatment, 27.5% who had 2 prior lines, and 21.3% who had 3 or more prior lines. Prior autologous hematopoietic stem cell transplant was reported for 7.5% of patients and prior radiotherapy for 61.3%.
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During a median follow-up of 18.7 months, the ORR was 44.9% compared with a rate of 20% in historic controls. A CR was achieved by 35.9% of patients and 32.1% achieved disease control. The median time to response was 2.8 months. There were 32.1% of patients who developed progressive disease.
The median DOR was not reached; however, there were 82.5% of patients who maintained their response at both 12 and 18 months. The overall survival rate at 12 and 18 months was 67.5% and 57.9%, respectively. The median overall survival was not yet reached.
There were 16.3% of patients who developed a grade 3-4 treatment-related adverse event (TRAE), with the most common being elevation of aspartate transaminase levels. A TRAE led to treatment discontinuation among 6.3% of patients. There were 5 deaths during the study, but they were not attributed to sugemalimab. Hypothyroidism of any grade occurred among 18.8% of patients and 5.0% of patients experienced an infusion-related reaction.
“These promising results directly inform an ongoing larger prospective randomized trial in this space comparing chemotherapy alone to chemotherapy with sugemalimab,” the authors concluded in their report.
Disclosures: This study was supported by CStone Pharmaceuticals (Suzhou) Co Ltd. Please see the original reference for a full list of disclosures.
Reference
Huang H, Tao R, Hao S, et al. Sugemalimab monotherapy for patients with relapsed or refractory extranodal natural killer/T-cell lymphoma (GEMSTONE-201): Results from a single-arm, multicenter, phase II study. J Clin Oncol. Published online March 30, 2023. doi: 10.1200/JCO.22.02367
