GSK’s Ris-Rez improved progression-free survival in the Phase III ARTEMIS-011 trial for relapsed osteosarcoma, supporting regulatory submission in China.
Written By: Fariha Sameen, PharmD
Reviewed By: Pharmacally Editorial Team
GSK’s licensed investigational antibody-drug conjugate (ADC), risvutatug rezetecan (Ris-Rez), met the primary endpoint of progression-free survival (PFS) in the pivotal Phase III ARTEMIS-011 trial (NCT06935409) in patients with relapsed or refractory osteosarcoma who had progressed after at least two prior lines of systemic therapy. Conducted in China by Hansoh Pharmaceutical Group, the study demonstrated statistically significant and clinically meaningful improvements in PFS compared with standard chemotherapy, while also showing favorable trends across secondary endpoints, including overall survival.
The positive results follow recently reported Phase III findings from the ARTEMIS-008 study in advanced or relapsed small-cell lung cancer (SCLC), in which Ris-Rez met its overall survival endpoint versus topotecan. Together, the studies make Ris-Rez the first B7-H3-targeted ADC to deliver positive Phase III outcomes across multiple tumor types.
B7-H3-Targeted ADC Addresses a Critical Treatment Gap
Ris-Rez is an investigational B7-H3-targeted antibody-drug conjugate comprising a fully human anti-B7-H3 monoclonal antibody linked to a topoisomerase I inhibitor payload. The therapy is designed to selectively deliver cytotoxic treatment to B7-H3-expressing tumor cells, a target broadly expressed across several solid malignancies.
Osteosarcoma is the most common primary bone cancer, affecting predominantly children, adolescents, and young adults. Although rare, with an estimated global incidence of approximately 3.4 cases per million people annually, the disease carries a poor prognosis after relapse. Patients whose disease progresses after at least two systemic treatment regimens have no approved standard of care, highlighting a substantial unmet medical need.
ARTEMIS-011 Demonstrates Clinically Meaningful Benefit
ARTEMIS-011 was a randomized, open-label, multicenter Phase III trial enrolling patients aged 12 years and older with relapsed or refractory osteosarcoma following at least two prior systemic therapies. Participants were randomized 2:1 to receive either Ris-Rez 12 mg/kg intravenously every three weeks or investigator-selected chemotherapy consisting of gemcitabine 1,000 mg/m² plus docetaxel 75 mg/m² every 21 days.
The trial met its primary endpoint by demonstrating a statistically significant and clinically meaningful improvement in progression-free survival compared with chemotherapy. Consistent benefit was also observed across secondary endpoints, including overall survival. The safety profile remained consistent with previous studies in osteosarcoma, and investigators reported no new safety signals.
Hansoh Pharma plans to use the Phase III results to support a regulatory submission in China.
Regulatory Momentum Builds Following Earlier Clinical Success
The Phase III success builds on encouraging findings from the Phase II ARTEMIS-002 study, which led the U.S. Food and Drug Administration (FDA) to grant Breakthrough Therapy Designation for Ris-Rez in January 2025 for the treatment of relapsed or refractory osteosarcoma.
Commenting on the results, Hesham Abdullah, Senior Vice President and Global Head of Oncology R&D at GSK, said the osteosarcoma data, together with the recent Phase III success in small-cell lung cancer, strengthen confidence in the broad therapeutic potential of Ris-Rez and further validate B7-H3 as an important target across multiple tumor types.
Global Development Expands Across Multiple Solid Tumors
Outside mainland China, Hong Kong, Macau, and Taiwan, GSK holds exclusive worldwide rights to develop and commercialize Ris-Rez under its licensing agreement with Hansoh Pharma.
The company is currently enrolling patients in EMBOLD Sarcoma-202, a global Phase Ib/II trial evaluating Ris-Rez in previously treated unresectable advanced or metastatic sarcomas, including osteosarcoma. Additional clinical programs are underway in lung cancer, prostate cancer, and other solid tumors.
Ris-Rez has also received multiple regulatory incentives supporting its global development, including FDA Breakthrough Therapy Designations for relapsed or refractory osteosarcoma and extensive-stage SCLC, FDA Orphan Drug Designation for SCLC, European Medicines Agency (EMA) PRIME designation for relapsed or refractory extensive-stage SCLC, and orphan drug designations in the European Union and Japan for SCLC-related indications. These designations, together with positive late-stage clinical data, position Ris-Rez as one of the leading B7-H3-targeted ADCs advancing toward potential global regulatory submissions.
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About the Writer
Fariha Sameen, PharmD (LinkedIn), is a clinical pharmacy professional with hands-on experience in patient counselling, medication review, therapeutic monitoring, and clinical documentation across multiple departments. She has experience identifying and assessing drug-related problems and supporting medication safety practices. Her interests include pharmacovigilance, ADR reporting, clinical research, and medical writing focused on clear, evidence-based communication.