Risvutatug Rezetecan Improves PFS in Phase 3 Osteosarcoma Trial

Risvutatug rezetecan (GSK5764227) demonstrated a statistically significant and clinically meaningful improvement in progression-free survival (PFS) compared with chemotherapy in patients with relapsed osteosarcoma, according to a news release from GSK.¹

The findings come from the phase 3 ARTEMIS-011 trial (NCT06935409), which evaluated risvutatug rezetecan, a B7-H3–targeted antibody-drug conjugate (ADC) vs gemcitabine plus docetaxel in patients with osteosarcoma who progressed or relapsed after at least 2 prior lines of systemic therapy.² The trial, conducted in China, met its primary end point of PFS, and consistent benefit was also observed across secondary end points, including overall survival (OS). The safety profile was consistent with prior findings, and no new safety signals were identified.

Trial Design

ARTEMIS-011 is an open-label, multicenter phase 3 trial with an estimated enrollment of 117 patients with relapsed osteosarcoma randomly assigned on a 2:1 basis.² Patients in the experimental arm were treated with risvutatug rezetecan intravenously at 12.0 mg/m² every 3 weeks until disease progression or other criteria for discontinuation were met. Patients aged 12 or older were eligible but they could not have received prior B7-H3–targeted therapy, topoisomerase I inhibitors, or gemcitabine/docetaxel chemotherapy.

Broader Development Context

The osteosarcoma results follow recently reported pivotal data for risvutatug rezetecan in advanced or relapsed small cell lung cancer(SCLC), making it the only B7-H3–targeted ADC to have delivered positive phase 3 outcomes across more than 1 tumor type, according to the news release.¹

GSK, which holds the rights to commercialize the ADC outside of China, is running EMBOLD Sarcoma-202 (NCT07602777), a global phase 1b/2 trial of the ADC in previously treated, unresectable advanced or metastatic sarcomas, including osteosarcoma, as part of a broader solid tumor program that also spans lung and prostate cancers. The agent has received several regulatory designations to date including breakthrough therapy designation in relapsed or refractory osteosarcoma and in relapsed or refractory extensive-stage SCLC, and orphan drug designation from the FDA, as well as in other regions.

Disease Background and Significance

Osteosarcoma is the most common primary bone cancer, accounting for 20% to 40% of all bone cancer cases and has a global incidence of approximately 3.4 cases per million people per year. It mainly affects children and young adults.^3,4 Following first-line chemotherapy, treatment options for relapsed osteosarcoma are severely limited, with no clear standard of care; after progression on 2 prior lines of therapy, no approved therapies are available.

Hansoh Pharmaceutical Group Co, Ltd, which holds rights to the ADC in China, plans to use the data to support a regulatory submission in the country.¹

“Building on recent pivotal data in [SCLC], these results strengthen our confidence in the broad potential of [risvutatug rezetecan] and validate B7-H3 as a promising target across multiple [tumor] types,” Hesham Abdullah, senior vice president, global head of oncology, R&D, at GSK, stated in the news release.

REFERENCES

1. GSK's Licensor Hansoh Pharma Announces Positive Results From a Second Phase III Trial for Ris-Rez in China. News release. GSK. July 28, 2026. Accessed July 29, 2026. https://tinyurl.com/ybxhp38t

2. Study of HS-20093 Versus Gemcitabine in Combination With Docetaxel in Treatment of Osteosarcoma After Previous Second-Line Treatment Failure (ARTEMIS-011). ClinicalTrials.gov. Updated 2026. Accessed July 29, 2026. https://clinicaltrials.gov/study/NCT06935409

3. Valery PC, Laversanne M, Bray F. Bone cancer incidence by morphological subtype: a global assessment. Cancer Causes Control. 2015;26(8):1127-1139. doi:10.1007/s10552-015-0607-3

4. WHO Classification of Tumours Editorial Board. Soft Tissue and Bone Tumours. 5th Edition, Vol. 3, WHO Classification of Tumours Series, International Agency for Research on Cancer, Lyon; 2020.