GSK Ris-Rez SCLC data unveiled at the 2026 World Conference on Lung Cancer (WCLC) show that the investigational antibody-drug conjugate cut the risk of death by 54% compared with topotecan in patients with relapsed small cell lung cancer whose disease progressed after platinum-based chemotherapy. The results come from ARTEMIS-008, a pivotal Phase III trial conducted in China by Hansoh Pharmaceutical Group Co., Ltd., GSK‘s licensing partner for risvutatug rezetecan (Ris-Rez) outside mainland China, Hong Kong, Macau and Taiwan. Presented in a Presidential Symposium session in Seoul, South Korea, the findings mark the first Phase III data to demonstrate an overall survival benefit for a B7-H3-targeted ADC in any tumour type.
In the trial, patients receiving Ris-Rez lived a median of 18.5 months compared with 10.3 months for those on topotecan, a commonly used option after progression on first-line therapy. The hazard ratio was 0.46 (95% CI: 0.35–0.62; p<0.0001), meeting the trial’s primary endpoint after a median follow-up of 12.2 months. Ris-Rez was evaluated in 230 patients versus 231 on topotecan, and investigators behind the GSK Ris-Rez SCLC programme say the magnitude of benefit is among the largest reported in this heavily pretreated population.
The overall survival benefit was reinforced by improvements across secondary efficacy measures. Independent review committee (IRC) assessment showed a median progression-free survival of 7.2 months for Ris-Rez versus 3.0 months for topotecan (HR 0.33; 95% CI: 0.25–0.42). IRC-assessed objective response rate reached 58.3% with Ris-Rez compared with 12.6% for topotecan, while disease control rate stood at 90.4% versus 60.2%, respectively.
For a disease where second-line options historically deliver modest benefit, the scale of these numbers stands out. GSK notes that relapsed small cell lung cancer has long been treated with chemotherapy regimens offering limited durability, and the company positions the GSK Ris-Rez SCLC dataset as evidence that a targeted antibody-drug conjugate can meaningfully outperform standard cytotoxic therapy in this setting. GSK plc trades on the London Stock Exchange and the New York Stock Exchange under the ticker GSK, and the company said the ARTEMIS-008 results were first announced in July 2026 ahead of Sunday’s full presentation in Seoul.
GSK Ris-Rez SCLC Trial Results: Survival and Response Data Explained
| Endpoint | Ris-Rez (n=230) | Topotecan (n=231) | Statistical Result |
|---|---|---|---|
| Overall survival (median) | 18.5 months | 10.3 months | HR 0.46 (95% CI: 0.35–0.62), p<0.0001 |
| Reduction in risk of death | 54% lower | Reference arm | Versus topotecan |
| Progression-free survival, IRC (median) | 7.2 months | 3.0 months | HR 0.33 (95% CI: 0.25–0.42) |
| Objective response rate, IRC | 58.3% | 12.6% | Not disclosed |
| Disease control rate, IRC | 90.4% | 60.2% | Not disclosed |
| Median follow-up | 12.2 months | 12.2 months | Not applicable |
Hesham Abdullah, GSK’s Senior Vice President and Global Head of Oncology, R&D, said the findings add to the growing evidence for Ris-Rez and represent a meaningful step forward for the company’s lung cancer portfolio. He noted that the survival improvement, combined with an encouraging safety profile, supports continued global development of the GSK Ris-Rez SCLC programme across earlier and later treatment settings.
Safety findings also favoured Ris-Rez. Grade 3 or higher treatment-related adverse events occurred in 60.9% of Ris-Rez patients compared with 78.2% of those on topotecan. The most common severe treatment-related adverse events associated with the GSK Ris-Rez SCLC therapy included decreased neutrophils, decreased white blood cells, anaemia, decreased lymphocytes and decreased platelets, haematologic effects that researchers describe as manageable and consistent with the known profile of this ADC class.
GSK Ris-Rez SCLC Safety Profile Shows Fewer Severe Side Effects Than Topotecan
| Safety Measure | Ris-Rez | Topotecan |
|---|---|---|
| Grade 3 or higher TRAEs (any) | 60.9% of patients | 78.2% of patients |
| Most common Grade 3+ TRAEs | Decreased neutrophils, decreased white blood cells, anaemia, decreased lymphocytes, decreased platelets | Not disclosed |
| Researcher classification | Manageable, consistent with known ADC-class effects | Not disclosed |
Jie Wang, M.D., Chair of the Medical Oncology Department at the National Cancer Center, Chinese Academy of Medical Sciences, and principal investigator of ARTEMIS-008, said relapsed small cell lung cancer remains difficult to treat once the disease returns, with few therapies offering meaningful survival gains. She noted that patients receiving Ris-Rez lived substantially longer while experiencing fewer severe side effects, calling the findings a potentially important advance for patients.
ARTEMIS-008 is a multicentre, randomised, open-label, active-controlled Phase III trial conducted in China, enrolling patients with limited- or extensive-stage SCLC whose disease progressed on or after first-line platinum-based therapy. Patients were randomised 1:1 to receive Ris-Rez at 8.0 mg/kg every three weeks or topotecan at 1.2 mg/m² on days 1–5 of each 21-day cycle. The primary endpoint was overall survival, with progression-free survival, objective response rate, disease control rate, duration of response and safety measured as secondary endpoints.
Hansoh Pharmaceutical Group Co., Ltd. sponsors and runs the trial in China, while GSK’s role centres on the licence it holds for markets outside mainland China, Hong Kong, Macau and Taiwan. That structure means the GSK Ris-Rez SCLC data generated in China feed directly into GSK’s own global regulatory and commercial strategy for the molecule, even though Hansoh leads day-to-day trial operations domestically. GSK said Hansoh plans to use the ARTEMIS-008 dataset to support future regulatory discussions in China, while GSK advances its own studies in other markets.
GSK Ris-Rez SCLC Development Programme and Regulatory Designations
Beyond China, GSK holds exclusive rights to develop and commercialise Ris-Rez outside mainland China, Hong Kong, Macau and Taiwan, and is advancing a global clinical programme spanning lung cancer, prostate cancer and other solid tumours. The molecule has received several regulatory designations, including orphan drug status in the United States, Japan and the European Union for SCLC, Breakthrough Therapy Designation from the FDA, and Priority Medicines (PRIME) designation from the European Medicines Agency for relapsed or refractory extensive-stage SCLC.
| Designation | Region / Agency | Indication |
|---|---|---|
| Orphan Drug Designation | United States (FDA) | Small cell lung cancer |
| Orphan Drug Designation | Japan | Small cell lung cancer |
| Orphan Drug Designation | European Union (EMA) | Small cell lung cancer |
| Breakthrough Therapy Designation | United States (FDA) | Relapsed/refractory extensive-stage SCLC |
| Priority Medicines (PRIME) Designation | European Union (EMA) | Relapsed/refractory extensive-stage SCLC |
The GSK Ris-Rez SCLC therapy is a novel antibody-drug conjugate targeting the B7-H3 protein, which is highly expressed across more than ten solid tumour types. GSK’s ambition is to develop the molecule across more than 40 indications by 2040, and more than 1,000 patients have already received Ris-Rez as part of the company’s global EMBOLD clinical trial programme. That programme includes a Phase III trial in late-line extensive-stage SCLC, known as EMBOLD SCLC-301, with additional Phase III studies planned in early-line SCLC and metastatic prostate cancer.
GSK Ris-Rez SCLC Outlook: What Comes Next for Patients and the Pipeline
GSK is also running the Phase III EMBOLD SCLC-301 trial, evaluating the GSK Ris-Rez SCLC therapy in relapsed extensive-stage disease outside China, with pivotal data expected next year. Alongside Ris-Rez, GSK’s oncology pipeline includes Mo-Rez, an ADC targeting B7-H4, and velzatinib, a selective KIT tyrosine kinase inhibitor, as the company expands from blood and women’s cancers into lung and gastrointestinal tumours.
| Metric | Value | Context |
|---|---|---|
| Share of global lung cancer diagnoses | 10–15% | Small cell lung cancer overall |
| Patients diagnosed at extensive stage | Approximately 70% | Global SCLC population |
| Median OS with current standard of care (ES-SCLC) | 12–13 months | Global benchmark |
| Disease characteristics | Rapid progression, early metastatic spread, frequent relapse | Global |
Small cell lung cancer accounts for roughly 10–15% of all lung cancer diagnoses worldwide and is marked by rapid progression, early metastatic spread and frequent relapse. About 70% of patients are diagnosed with extensive-stage disease, and median overall survival with current standard-of-care therapies is approximately 12 to 13 months, underscoring the need identified by the GSK Ris-Rez SCLC development programme for new treatment options in this hard-to-treat cancer.
GSK frames its broader oncology ambition as increasing overall quality of life, maximising survival and changing the course of disease, expanding beyond its established focus on blood and women’s cancers into lung and gastrointestinal tumours. Within that strategy, the GSK Ris-Rez SCLC programme sits alongside Mo-Rez and velzatinib as one of three priority assets the company is advancing toward what it describes as a bold ambition to launch multiple new lung cancer options over the next five years. GSK’s focus in this area is on medicines that deliver durable responses, overcome resistance and reduce treatment burden across both small cell and non-small cell lung cancers, drawing on validated targets and modalities including targeted small molecules and antibody-drug conjugates.
GSK notes that forward-looking statements in its announcement are subject to risks and uncertainties that could cause actual results to differ materially, as detailed in the company’s Annual Report on Form 20-F for 2025 and its Q2 2026 results. All figures in this article are drawn directly from GSK’s 13 September 2026 press release and the ARTEMIS-008 trial data presented at WCLC 2026; no figures have been estimated, and any data point not disclosed in the source material is flagged as “Not disclosed” in the tables above.
