GSK’s bet on Hansoh Pharma is continuing to bear fruit for its oncology portfolio, as the Chinese biotech posted another Phase III win with its antibody-drug conjugate (ADC) – this time in a type of bone cancer.
Risvutatug rezetecan’s (ris-rez’s) second Phase III success stems from the Chinese ARTEMIS-011 study (NCT06935409), in which Hansoh pitted the B7-H3-targeting ADC against standard of care (SoC) chemotherapy in patients with third-line osteosarcoma. During the trial, ris-rez triggered a statistically significant improvement in progression-free survival (PFS) – meeting the study’s primary endpoint.
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Ris-rez also demonstrated consistent benefit across secondary endpoints, GSK claims, with researchers observing improvements in overall survival (OS) in the investigational treatment group versus the SoC arm.
Patients with osteosarcoma also tolerated the drug well, with no new safety signals observed following treatment.
GSK ramps up oncology efforts
Ris-rez’s success in osteosarcoma, a rare and aggressive form of bone cancer, closely follows Hansoh posting a late-stage win for the drug through the ARTEMIS-008 trial (NCT06498479), which evaluated ris-rez in patients with advanced or relapsed small cell lung cancer (SCLC). In this study, the ADC significantly improved overall survival (OS) versus SoC chemotherapy.
This duo of triumphs for Hansoh will be welcome news for GSK, which originally licensed ris-rez back in 2023 for up to $1.5bn amid the company’s bid to revive its standing in the oncology space after stepping away from the disease area back in 2015. In a Q2 earnings call, GSK executives noted that they increasingly view oncology as a major contributor to the company’s future growth, and that an expansive pipeline, instead of a couple of assets, will bolster the company’s bottom line.
This strategy has already paid dividends for GSK, as the company recently secured its first lung cancer approval with Nuvalent-acquired ROS1-positive non-small cell lung cancer (NSCLC) asset, Jideytro (zidesamtinib), which got the US regulatory greenlight earlier in July.
Now, to take steps toward potential approval outside of China for ris-rez, GSK is conducting the global Phase Ib/II EMBOLD Sarcoma-202 study, evaluating ris-rez’s potential in pretreated, unresectable advanced or metastatic sarcomas.
If ris-rez were to reach the market, it would join Jideytro, as well as multiple myeloma ADC, Blenrep (belantamab mafodotin) in GSK’s oncology treatment arsenal. US regulators opted to renew Blenrep’s approval in the third line setting after the drug’s approval was temporarily withdrawn due to it failing a confirmatory study.
Osteosarcoma remains an area of unmet need
Currently, the SoC treatment for osteosarcoma revolves around chemotherapy and immunosuppressants like methotrexate – a standard that has remained the same for more than four decades.
If ris-rez were to demonstrate global benefit in the metastatic population, the drug could hold significant benefit, as patients are currently subject to a worse prognosis, with survival rates ranging from 5% to 30%.
In October 2025, OS Therapies announced that its cancer vaccine, OST-HER2, boosted OS in osteosarcoma patients in a Phase IIb trial – prompting the company to vie for the drug’s regulatory approval in the US, UK and EU.
