Hansoh Pharmaceutical and its partner GSK reported that risvutatug rezetecan (ris-rez) met the primary endpoint in a Phase III study (ARTEMIS-011) in third-line osteosarcoma, adding to earlier setbacks and wins for the B7-H3 ADC class. Hansoh also pointed to other ongoing Phase III efforts across the program’s broader development plan. The update follows a July 10 announcement that the ADC met the primary overall survival endpoint in second-line small cell lung cancer (SCLC) under ARTEMIS-008. Together, the readouts extend the evidentiary base for B7-H3 as a target in hard-to-treat and underserved cancers. With additional development underway, the next regulatory steps will likely hinge on the maturity of endpoint timing, safety monitoring across lines of therapy, and comparative positioning versus other ADCs in similar stages and indications. For the ADC field, the results reinforce how target selection plus dose-and-line strategies are increasingly decisive—especially when companies are competing for durable survival endpoints rather than response rates.