ESMO Congress 2026

Among the published materials, the ADC category already has a Phase III randomized-study framework in another tumor type: sonesitatug vedotin plus capecitabine, with or without rilvegostomig, in CLDN18.2-positive advanced or metastatic gastric or gastroesophageal junction cancer ^[1]. However, that abstract discloses only the study design and no efficacy results ^[1]. The published literature provided contains no Phase III report directly corresponding to risvutatug rezetecan or ARTEMIS-011, so its evidence cannot be extrapolated from other ADCs.

The study actually presented at the meeting was the Phase III ARTEMIS-011 trial: 122 patients aged ≥12 years with relapsed/refractory osteosarcoma who had received ≥2 prior lines of systemic therapy received risvutatug rezetecan (Ris-Rez) or gemcitabine plus docetaxel. BICR-assessed median PFS was 5.5 months versus 1.4 months, HR 0.33, p<0.0001; ORR was 15% versus 2%, and DCR was 76% versus 33%. OS remained immature, with HR 0.51, and median follow-up was 7.1 months. Grade ≥3 treatment-related adverse events occurred in 92.5% versus 83.3%.

The main-site news independently covered the same Phase III study and identified the drug as 瑞康立伏妥塔单抗（HS-20093）. It confirmed that the primary endpoint was met, stated that 122 patients who had failed at least second-line treatment were enrolled, and added the 95% CI of 0.20-0.55. Its BICR PFS of 5.5 months versus 1.4 months, HR=0.33, P<0.0001 and 67% reduction in the risk of progression or death were consistent with the meeting posts. The news did not provide OS maturity or grade ≥3 treatment-related adverse-event figures.

Relative to the prior understanding that options have been limited for years in relapsed/refractory osteosarcoma, this result advanced a B7-H3 ADC to a Phase III direct comparison with chemotherapy and showed improvements in PFS and DCR. However, ORR remained low, suggesting that improved disease control does not equate to broad tumor shrinkage. Key limitations are the short 7.1-month follow-up, immature OS and high incidence of grade ≥3 treatment-related adverse events; ultimate survival benefit and impact on treatment pathways remain to be confirmed.