Ris-Rez shows 61% response rate in first global small cell lung cancer data

GSK has reported the first global clinical data for risvutatug rezetecan, also known as Ris-Rez, in patients with relapsed extensive-stage small cell lung cancer.

The findings come from the Phase Ib dose-optimisation portion of the EMBOLD PanTumour-101 study and were presented at the 2026 European Society for Medical Oncology Congress in Madrid.

Ris-Rez is an investigational B7-H3-directed antibody drug conjugate being developed for several solid tumours.

At the 8 mg/kg dose, the treatment achieved a confirmed objective response rate of 61% among evaluable patients.

Eleven of 18 patients responded, with a 95% confidence interval of 35.7% to 82.7%.

At the lower 6 mg/kg dose, the confirmed objective response rate was 32%, with seven of 22 evaluable patients responding.

GSK said the findings, together with previously reported Phase III results from Hansoh Pharma’s ARTEMIS-008 study in China, supported selection of the 8 mg/kg dose for further development.

That dose is now being evaluated in the global Phase III EMBOLD SCLC-301 study.

Hesham Abdullah, Senior Vice President and Global Head of Oncology Research and Development at GSK, said the new findings expand the evidence base for Ris-Rez beyond the previously reported Chinese population.

He said GSK is continuing to accelerate development of the medicine in extensive-stage small cell lung cancer, where disease relapse is common and later-line treatment options remain limited.

The safety profile was considered manageable across both dose levels after a median follow-up of 100.5 days.

Grade 3 or higher treatment-related adverse events were reported in 42% of patients receiving 8 mg/kg and 15% of those receiving 6 mg/kg.

Haematological toxicities were the most common severe treatment-related adverse events.

Interstitial lung disease was reported in one of 50 patients across the study population, representing an overall incidence of 2%.

The case was classified as grade 2.

Hye Ryun Kim, MD, PhD, of Yonsei Cancer Center and an investigator in EMBOLD PanTumour-101, said relapsed extensive-stage small cell lung cancer remains difficult to treat and is associated with poor long-term survival.

She said the observed response rates and safety profile support continued clinical development of Ris-Rez in this setting.

The Phase Ib results are being presented alongside additional findings from the broader EMBOLD development programme.

These include global dose-escalation data from EMBOLD PanTumour-101, an analysis of interstitial lung disease across the early Ris-Rez programme and the design of the Phase III EMBOLD SCLC-301 trial.

GSK is also presenting real-world data from the RESONANCE study examining treatment patterns after relapse in extensive-stage small cell lung cancer.

The company said the findings highlight the continued lack of a clearly established treatment standard in later-line disease.

---

---

Related Topics and Keywords

ADC, antibody drug conjugate, B7-H3, Biopharma, clinical trials, EMBOLD PanTumour-101, EMBOLD SCLC-301, ES-SCLC, ESMO 2026, extensive-stage small cell lung cancer, GSK, lung cancer, objective response rate, Oncology, pharma news, Phase Ib, phase III, Ris-Rez, risvutatug rezetecan, SCLC, small-cell lung cancer