GSK has reported promising global clinical trial results for its experimental cancer drug risvutatug rezetecan (Ris-Rez).

 

This, with the treatment achieving a confirmed tumour response rate of 61% in patients with relapsed extensive-stage small cell lung cancer (ES-SCLC) at the 8 mg/kg dose.

 

Data from the Phase Ib dose-optimisation portion of the EMBOLD PanTumour-101 trial showed anti-tumour activity alongside a manageable safety profile, strengthening the case for further development of the investigational B7-H3-targeted antibody-drug conjugate (ADC). 

 

The findings build on recently reported positive Phase III results from a Chinese trial involving patients with small cell lung cancer (SCLC).

 

At the 8 mg/kg dose, 11 of 18 evaluable patients achieved a confirmed objective response, translating to a response rate of 61%. The rate was 32% at the 6 mg/kg dose, with seven of 22 patients responding.

 

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 trial reported a manageable safety profile across both dose levels after a median follow-up of 100.5 days, although treatment-related adverse events were more frequent at the higher dose.

 

Grade 3 or higher treatment-related adverse events (TRAEs) occurred in 42% of patients receiving 8 mg/kg, compared with 15% among those receiving 6 mg/kg. Haematological events were the most common.

 

Interstitial lung disease (ILD), a potentially serious lung complication, was reported in one of the 50 patients assessed, an overall incidence of 2%. The case was moderate, classified as grade 2.

 

Hye Ryun Kim, 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.”

 

GSK plans to present additional findings from its EMBOLD clinical development programme at ESMO 2026, including global dose-escalation results from EMBOLD PanTumour-101, an analysis of ILD across the early Ris-Rez clinical programme and details of the global Phase III EMBOLD SCLC-301 trial design.