GSK’s Ris-Rez Cuts Death Risk in Relapsed SCLC

London, United Kingdom, September 13, 2026

Ris-Rez Demonstrates Significant Survival Benefit

The ARTEMIS-008 trial is a pivotal, randomized, open-label Phase III clinical study evaluating Ris-Rez against topotecan in patients with limited- or extensive-stage SCLC whose disease progressed during or after first-line platinum-based therapy. The trial randomized 461 patients, with 230 receiving Ris-Rez and 231 receiving topotecan. The statistically significant overall survival result represents the first Phase III evidence of an overall survival benefit for a B7-H3-targeted antibody-drug conjugate (ADC) in any tumor type, according to GSK. The survival advantage was accompanied by consistent improvements across important secondary efficacy measures. Median progression-free survival (PFS) assessed by an independent review committee was 7.2 months with Ris-Rez versus 3.0 months with topotecan, corresponding to a 67% reduction in the risk of disease progression or death (HR 0.33; 95% CI, 0.25–0.42). The objective response rate was 58.3% versus 12.6%, while the disease control rate reached 90.4% versus 60.2%, respectively. These results indicate that the survival benefit was supported by substantial improvements in tumor response and disease control.

B7-H3 ADC Advances Relapsed Lung Cancer Research

Ris-Rez is an investigational B7-H3-targeted antibody-drug conjugate being developed by GSK and its licensing partner Hansoh Pharmaceutical Group. The therapy is designed to target B7-H3, a protein highly expressed across multiple solid tumors. GSK holds exclusive rights to develop and commercialize Ris-Rez outside mainland China, Hong Kong, Macau and Taiwan, and is pursuing a broader global clinical development program in small cell lung cancer, prostate cancer and other solid tumors. The ARTEMIS-008 findings are particularly important because relapsed SCLC remains a difficult-to-treat cancer, with patients frequently experiencing disease progression after initial platinum-based therapy. Available treatment options in later-line disease remain limited, creating a significant need for therapies capable of extending survival. The substantial difference in median overall survival observed with Ris-Rez provides important evidence for continued development of the B7-H3-targeted approach. GSK is also evaluating Ris-Rez in additional clinical settings. Its global EMBOLD clinical development program includes the Phase III EMBOLD SCLC-301 trial in relapsed extensive-stage SCLC, with pivotal data expected in 2027. Additional Phase III studies are planned in earlier-line SCLC and metastatic prostate cancer. More than 1,000 patients have received Ris-Rez across the company’s global clinical program.

Safety Profile Supports Continued Development

The survival improvement was accompanied by a lower incidence of severe treatment-related adverse events compared with topotecan. Grade 3 or higher treatment-related adverse events occurred in 60.9% of patients receiving Ris-Rez, compared with 78.2% of patients receiving topotecan. The most common severe treatment-related events with Ris-Rez were hematologic abnormalities, including decreased neutrophils, decreased white blood cells, anemia, decreased lymphocytes and decreased platelets. GSK described these effects as manageable and consistent with the known safety profile of the therapeutic class. Ris-Rez remains an investigational therapy and has not been established as an approved treatment for relapsed SCLC on the basis of these results alone. The program has, however, received several regulatory designations, including U.S., Japanese and European orphan drug designations for SCLC, as well as U.S. Breakthrough Therapy Designation and EMA PRIME designation for relapsed or refractory extensive-stage SCLC. The ARTEMIS-008 findings provide a significant clinical-development milestone for GSK’s B7-H3 ADC program and could help shape the next stage of development for this emerging targeted therapy.

Source: GSK press release