GSK plc (LON:GSK, NYSE: GSK) has announced the first global data for risvutatug rezetecan (Ris-Rez), its investigational B7-H3-targeted antibody-drug conjugate (ADC), in patients with relapsed extensive-stage small cell lung cancer (ES-SCLC). Results from the phase Ib dose-optimisation portion of the EMBOLD PanTumour-101 trial showed positive anti-tumour activity and a manageable safety profile, adding to recently reported positive phase III data in patients with SCLC in China.1
In the trial, Ris-Rez achieved a confirmed objective response rate (ORR) of 61% among evaluable patients at the 8 mg/kg dose (n=11/18; 95% CI: 35.7-82.7), compared with 32% at the 6 mg/kg dose (n=7/22; 95% CI: 13.9-54.9). These findings will be presented in a poster session at the European Society for Medical Oncology (ESMO) Congress 2026 in Madrid, Spain. Along with data from Hansoh’s phase III ARTEMIS-008 study in SCLC, this data supported selection of the 8 mg/kg dose currently being evaluated in GSK’s global phase III EMBOLD SCLC-301 study.
Hesham Abdullah, Senior Vice President, Global Head of Oncology, R&D, GSK said, “Today’s first global data for Ris-Rez build on the statistically significant overall survival benefit recently reported in Hansoh’s pivotal Chinese trial. As the data for Ris-Rez continues to grow, we remain focused on accelerating development in extensive-stage small cell lung cancer, where patients often relapse quickly and urgently need more treatment options.”
The safety profile was manageable across both dose levels at a median follow-up of 100.5 days. Grade 3 or higher treatment-related adverse events (TRAEs) were observed in 42% of patients receiving 8 mg/kg and 15% of those receiving 6 mg/kg, with haematological events being the most common. The overall rate of interstitial lung disease (ILD) was low (2%; 1 out of 50 patients) and the case was moderate (grade 2).
Hye Ryun Kim, MD, PhD, Division of Medical Oncology, Yonsei Cancer Center, and a study investigator in the EMBOLD PanTumour-101 study, said, “Extensive-stage small cell lung cancer remains one of the most aggressive cancers we treat, with five-year survival rates typically in the single digits. Patients whose disease relapses often have limited options, and current therapies can be difficult to tolerate. The response rates and manageable safety profile observed with Riz-Rez are encouraging and support its ongoing development in this setting.”
These data will be presented alongside a broader set of findings from the EMBOLD programme at ESMO 2026, including global dose-escalation results from EMBOLD PanTumour-101, an analysis of ILD across the Ris-Rez early clinical programme, and the design of the global phase III EMBOLD SCLC-301 study. Real-world evidence from the RESONANCE study further demonstrates the complexity of treatment decision-making after relapse in ES-SCLC and highlights the absence of a clear treatment standard in later lines of therapy. Together, these findings contribute to the growing body of evidence for Ris-Rez and reflect GSK’s focus on advancing targeted medicines where significant patient need and scientific opportunity remain.
