In a Chinese phase II study (GEMSTONE-201) reported in the Journal of Clinical Oncology, Huang et al found that the PD-L1 inhibitor sugemalimab produced durable responses in patients with relapsed or refractory extranodal natural killer/T-cell lymphoma.
Study Details
In the multicenter trial, 78 evaluable patients enrolled between June 2018 and May 2021 received sugemalimab at 1,200 mg once every 3 weeks for up to 24 months or until disease progression, death, or study withdrawal. A total of 68% of patients had stage IV disease and 49% had received two or more lines of systemic therapy. The primary endpoint was objective response rate on independent radiologic review committee assessment.
Key Findings
At data cutoff in February 2022, median follow-up was 18.7 months. Objective response was observed in 35 patients (44.9%, 95% confidence interval [CI] = 33.6%–56.6%), including complete response in 28 (35.9%). An additional eight patients (10.3%) had stable disease, yielding a disease control rate of 55.1%.
Median time to response was 2.8 months (range = 1.4–11.1 months). Median duration of response was not reached (95% CI = 19.7 months to not reached); 91.3%, 82.5%, and 82.5% of responses were maintained at 6, 12, and 18 months.
Median overall survival was not reached (95% CI = 14.0 months to not reached). Overall survival rates at 6, 12, and 18 months were 79.2%, 67.5%, and 57.9%.
Among 80 patients in the safety population, grade ≥ 3 adverse events occurred in 32 (40.0%); serious adverse events occurred in 23.8%. Adverse events led to treatment discontinuation in 13.8%. Adverse events led to death in five patients (6.3%); death was due to unknown causes in two, upper gastrointestinal hemorrhage in one, hemophagocytic lymphohistiocytosis in one, and septic shock in one.
The investigators concluded, “Sugemalimab showed robust and durable antitumor activity in relapsed/refractory extranodal natural killer/T-cell lymphoma. Treatment was well tolerated with expected safety profile for this drug class.”
Huiqiang Huang, MD, of the Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported by CStone Pharmaceuticals (Suzhou) Co Ltd, Suzhou, China. For full disclosures of the study authors, visit ascopubs.org.
