Hansoh's Ris-Rez hits PFS endpoint in second phase III osteosarcoma trial

GSK plc said on July 28, 2026 that its licensor Hansoh Pharmaceutical Group Co., Ltd. announced positive results from a second phase III trial of risvutatug rezetecan (Ris-Rez). The trial, ARTEMIS-011, was conducted in China and evaluated Ris-Rez in patients with osteosarcoma who had progressed or relapsed after at least two prior lines of systemic therapy, and it met its primary endpoint of progression-free survival.¹

In the trial, Ris-Rez, a B7-H3-targeted antibody-drug conjugate, showed statistically significant and clinically meaningful improvements in progression-free survival compared with chemotherapy, according to the company.¹ Benefit was also consistently observed across secondary endpoints, including overall survival.¹ The safety profile matched prior findings in this tumor type, with no new safety signals identified.¹ Hansoh Pharma plans to use these data for a regulatory submission in China.¹

GSK is separately running a global trial called "EMBOLD Sarcoma-202," a phase Ib/II study testing Ris-Rez in previously treated, unresectable advanced or metastatic sarcomas, including osteosarcoma, as part of GSK's broader oncology development program under its exclusive rights to Ris-Rez outside mainland China, Hong Kong, Macau and Taiwan.¹ Ris-Rez already holds US FDA Breakthrough Therapy Designation for relapsed or refractory osteosarcoma.¹

The company said this makes Ris-Rez the only B7-H3-targeted ADC to post positive phase III results across multiple tumor types, following earlier pivotal data in advanced or relapsed small-cell lung cancer.¹ GSK noted that treatment options for relapsed osteosarcoma patients are severely limited after first-line chemotherapy, with no clear standard of care, and even fewer options after two prior lines of treatment, with no approved therapies.¹