Patients with relapsed small-cell lung cancer whose disease had progressed on or after platinum-based chemotherapy lived longer on risvutatug rezetecan than on topotecan, according to results from the randomized Phase III ARTEMIS-008 trial presented at the IASLC 2026 World Conference on Lung Cancer. The risk of death was 54% lower with the B7-H3-directed antibody-drug conjugate, the trial found.

ARTEMIS-008 (NCT06498479) is a multicenter, open-label, randomized Phase III study, the International Association for the Study of Lung Cancer said. It randomized 461 patients in China in equal groups to risvutatug rezetecan at 8.0 mg/kg every three weeks or topotecan at 1.2 mg/m² on days 1 through 5 every three weeks. More than 80% of the patients had previously received PD-(L)1 inhibitors. Overall survival was the primary endpoint, and progression-free survival, objective response rate, disease control rate and safety were among the key secondary endpoints.

At a June 6, 2026 data cutoff, after a median follow-up of 12.2 months, median overall survival was 18.5 months with risvutatug rezetecan against 10.3 months with topotecan, with a hazard ratio of 0.46 (95% CI, 0.35–0.62; P < 0.0001). The overall survival benefit was consistent across relevant subgroups, the association said. Blinded independent central review also favored the antibody-drug conjugate: median progression-free survival was 7.2 months versus 3.0 months (HR 0.33; 95% CI, 0.25–0.42), the objective response rate was 58.3% versus 12.6% and the disease control rate was 90.4% versus 60.2%. Investigator-assessed outcomes were consistent with the central review.

Grade 3 or higher treatment-related adverse events occurred in 60.9% of patients on risvutatug rezetecan and 78.2% of those on topotecan. The most common were hematologic toxicities, including decreased neutrophil count, decreased white blood cell count, anemia, decreased lymphocyte count and decreased platelet count.

Professor Jie Wang of the National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences Peking Union Medical College in Beijing, said the trial showed a statistically significant and clinically meaningful overall survival benefit over topotecan in patients whose cancer progressed after platinum-based therapy, with a favorable safety profile. He said the results suggest the treatment has the potential to define a new standard of care in relapsed small-cell lung cancer.