GSK plc reported that its experimental antibody-drug conjugate risvutatug rezetecan, also known as Ris-Rez, significantly reduced the risk of death in patients with relapsed small cell lung cancer, meeting the primary endpoint of its phase III ARTEMIS-008 trial.
Presented Saturday at the 2026 World Conference on Lung Cancer in Seoul, South Korea, the data showed a 54% reduction in the risk of death compared with topotecan, the standard-of-care comparator. The hazard ratio was 0.46 (95% CI: 0.35–0.62; p < 0.0001).
Patients receiving Ris-Rez lived a median of 18.5 months, compared with 10.3 months for those on topotecan. Progression-free survival, assessed by an independent review committee, was 7.2 months versus 3.0 months. The objective response rate stood at 58.3% for Ris-Rez against 12.6% for topotecan, while the disease control rate was 90.4% versus 60.2%.
ARTEMIS-008 enrolled 461 patients in China whose disease had progressed following platinum-based first-line therapy. Median follow-up was 12.2 months. Small cell lung cancer accounts for roughly 10-15% of all lung cancer diagnoses worldwide, and approximately 70% of patients are diagnosed with extensive-stage disease.
Safety findings showed that grade 3 or higher treatment-related adverse events occurred in 60.9% of patients on Ris-Rez, compared with 78.2% on topotecan. The most common severe side effects with Ris-Rez were decreased neutrophils, decreased white blood cells, anaemia, decreased lymphocytes, and decreased platelets.
GSK holds exclusive rights to develop and commercialize Ris-Rez outside mainland China, Hong Kong, Macau and Taiwan. The company is concurrently running a second phase III trial, EMBOLD SCLC-301, in relapsed extensive-stage small cell lung cancer, with pivotal data expected in 2027. Hansoh Pharmaceutical Group Co., Ltd. is the co-development partner for the asset in China.
