GSK plc licensor Hansoh Pharmaceutical Group announced positive Overall Survival (OS) data from ARTEMIS-008, its pivotal phase 3 trial in China evaluating the B7-H3-targeted Antibody Drug Conjugate (ADC) risvutatug rezetecan (Ris-Rez) versus topotecan in patients with relapsed Small Cell Lung Cancer (SCLC) whose disease progressed following platinum-based first-line therapy.

These results, first announced in July, are the first phase 3 data to demonstrate an OS benefit for a B7-H3 ADC in any tumor type.

In the trial, Ris-Rez reduced the risk of death by 54 percent compared with topotecan, a commonly used treatment option following progression on first-line therapy, meeting the trial's primary endpoint after a median follow-up of 12.2 months (HR 0.46; 95 percent CI: 0.35-0.62, p<0.0001).

Patients receiving Ris-Rez lived a median of 18.5 months (n=230) compared with 10.3 months for those receiving topotecan (n=231). These results were presented in a Presidential Symposium session at the 2026 World Conference on Lung Cancer (WCLC) in Seoul, South Korea.

Hesham Abdullah, Senior Vice President, Global Head of Oncology, R&D, GSK said, "These results add to the growing body of evidence for Ris-Rez and mark an important step forward for our lung cancer portfolio. The significant improvement in survival observed in this study, together with an encouraging safety profile, provide further momentum for GSK’s global development of Ris-Rez across later-line and earlier treatment settings for Small Cell Lung Cancer."

The OS benefit observed was supported by improvements across key secondary efficacy endpoints. Median Progression-Free Survival (PFS) as assessed by an Idependent Review Committee (IRC) was 7.2 months versus 3.0 months (HR 0.33; 95 percent CI: 0.25-0.42); IRC-assessed Objective Response Rate (ORR) was 58.3 percent versus 12.6 percent; and IRC-assessed disease control rate was 90.4 percent versus 60.2 percent for Ris-Rez and topotecan, respectively.

Patients receiving Ris-Rez experienced fewer severe Treatment-Related Adverse Effects (TRAEs) than those receiving topotecan, with grade 3 or higher TRAEs occurring in 60.9 percent versus 78.2 percent of patients, respectively. The most common grade 3 or higher TRAEs with Ris-Rez were decreased neutrophils, decreased White Blood Cells (WBCs), anaemia, decreased lymphocytes and decreased platelets. These haematologic TRAEs are considered manageable and consistent with the known side effects in this class of medicines.

Jie Wang, MD, Chair, Medical Oncology Department, National Cancer Center, Chinese Academy of Medical Sciences and Principal Investigator of the ARTEMIS-008 trial, said, “Relapsed Small Cell Lung Cancer remains one of the most challenging cancers to treat, with few therapies delivering meaningful improvements in survival once the disease returns. In ARTEMIS-008, patients receiving Ris-Rez lived substantially longer while experiencing lower rates of severe treatment-related side effects. These findings suggest Ris-Rez could represent an important advance for patients.”

GSK holds exclusive rights to develop and commercialise Ris-Rez outside mainland China, Hong Kong, Macau and Taiwan, and is advancing a broad global clinical development program across lung cancer, prostate cancer and other solid tumors, including the phase 3 EMBOLD SCLC-301 trial in relapsed extensive-stage SCLC, with pivotal data expected next year.