Risvutatug rezetecan lifted median survival from 10.3 to 18.5 months in relapsed small-cell lung cancer
In the phase 3 ARTEMIS-008 trial, presented in the opening Presidential Symposium of the World Conference on Lung Cancer in Seoul, the B7-H3-directed antibody-drug conjugate risvutatug rezetecan kept patients with relapsed small-cell lung cancer alive for a median 18.5 months against 10.3 months with the chemotherapy topotecan, a 54 percent lower risk of death. Response rates and progression-free survival also favoured the drug, and severe side effects were less frequent. Developer Hansoh Pharma has already filed for approval in China.
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A 54 percent lower risk of death at the interim analysis
ARTEMIS-008 is a phase 3 trial run at centres in China by Hansoh Pharma, a Chinese drugmaker traded in Hong Kong, and its interim results were presented on 13 September in the first Presidential Symposium of the IASLC 2026 World Conference on Lung Cancer in Seoul, the annual meeting of the International Association for the Study of Lung Cancer. Risvutatug rezetecan, known as Ris-Rez, is an antibody-drug conjugate: an antibody against the B7-H3 protein on tumour cells that carries a cell-killing topoisomerase I inhibitor. The 461 people in the trial had small-cell lung cancer that had progressed on or after platinum-based chemotherapy, and more than 80 percent had already received a PD-1 or PD-L1 inhibitor; the arms were split 1:1 between Ris-Rez at 8.0 mg/kg every three weeks and topotecan at 1.2 mg/m² on days 1 to 5 of each three-week cycle. At the 6 June 2026 data cutoff, after a median follow-up of 12.2 months, median overall survival was 18.5 months with Ris-Rez and 10.3 months with topotecan, a hazard ratio of 0.46 with a 95 percent confidence range of 0.35 to 0.62, which the IASLC describes as a 54 percent reduction in the risk of death. Hansoh adds that 64.5 percent of the Ris-Rez arm was alive at 12 months against 43.3 percent of the topotecan arm, with a consistent benefit across subgroups.[1], [2]
Response rates rose and severe side effects fell
Independent central review favoured Ris-Rez on every key secondary measure. Median progression-free survival was 7.2 months against 3.0 months with topotecan, a hazard ratio of 0.33 with a range of 0.25 to 0.42; the objective response rate was 58.3 percent against 12.6 percent, and the disease control rate 90.4 percent against 60.2 percent. Grade 3 or higher treatment-related adverse events occurred in 60.9 percent of Ris-Rez patients and 78.2 percent of topotecan patients; the most common were blood toxicities, mostly falls in blood-cell counts and anaemia. Hansoh reports that grade 3 or higher platelet decreases affected 13.9 percent on Ris-Rez against 59.7 percent on topotecan, that fatal blood events occurred only in the topotecan arm, that discontinuations and deaths from treatment-related events were comparable, and that interstitial lung disease was mostly grade 1 or 2 with no grade 4 or fatal cases; median duration of response was 6.9 months against 5.6 months.[1], [2]
A first survival win for the B7-H3 class and a filing already under review in China
Hansoh calls ARTEMIS-008 the first phase 3 trial to show an overall survival benefit for a B7-H3-directed antibody-drug conjugate in small-cell lung cancer, and presenting investigator Jie Wang of the Cancer Hospital of the Chinese Academy of Medical Sciences in Beijing said the results point to the drug's potential to define a new standard of care in relapsed disease. China's National Medical Products Administration accepted a biologics licence application for Ris-Rez in relapsed small-cell lung cancer on 2 September 2026 and granted it priority review, and the company counts 13 regulatory designations for the drug across China, the United States, Japan and Europe. The British drugmaker GSK holds the rights to develop and sell Ris-Rez outside mainland China, Hong Kong, Macau and Taiwan, and phase 3 trials are under way in non-small cell lung cancer, osteosarcoma, prostate cancer and oesophageal cancer. The trial is confined to China, and its results so far exist only as a conference abstract; there is no journal paper yet.[2], [1]
