GSK (LSE:GSK) reported the first global data for risvutatug rezetecan (Ris-Rez), its investigational B7-H3-targeted antibody-drug conjugate, 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 a confirmed objective response rate of 61% among evaluable patients at the 8mg/kg dose, compared with 32% at the 6mg/kg dose.
The findings will be presented in a poster session at the European Society for Medical Oncology Congress in Madrid, and add to positive phase III data reported last month from a Chinese trial of the same drug run by partner Hansoh Pharma.
Together with that Chinese data, the phase Ib results supported GSK's selection of the 8mg/kg dose now being tested in its global phase III EMBOLD SCLC-301 study.
"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," said Hesham Abdullah, GSK's senior vice president and global head of oncology, R&D.
The safety profile was manageable at a median follow-up of 100.5 days, with grade 3 or higher treatment-related adverse events in 42% of patients on the higher dose and 15% on the lower dose, most commonly haematological.
Interstitial lung disease occurred in just one of the 50 patients studied.
GSK licensed exclusive worldwide rights to Ris-Rez from Hansoh Pharma, excluding mainland China, Hong Kong, Macau and Taiwan, and more than 1,000 patients have now received the drug across its global EMBOLD trial programme, which also includes a phase III study in metastatic castration-resistant prostate cancer.
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- 14/09/26GSK's Ris-Rez cuts death risk 54% in lung cancer trial
- 15/07/26GSK completes Nuvalent acquisition, adding lung cancer drugs
- 10/07/26Hansoh Phase III win bolsters GSK's global case for Ris-Rez in lung cancer
Ris-Rez is one of two priority antibody-drug conjugates, alongside Mo-Rez, that GSK has identified as central to expanding its oncology business beyond haematology and women's cancers into lung and gastrointestinal cancers, a push reinforced by its completed acquisition of Nuvalent in July, which added three lung cancer assets now under US regulatory review.
The drug has already picked up Breakthrough Therapy designation in the US, PRIME designation from the EMA, and orphan drug status in the US, Japan and the EU for small cell lung cancer.
Extensive-stage small cell lung cancer accounts for roughly 70% of small cell lung cancer diagnoses, and median overall survival on current standard-of-care treatment is approximately 12 to 13 months, according to the company.