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Overview

GSK5764227 (HS-20093) is an investigational, B7‑H3–targeted antibody–drug conjugate (ADC) licensed by GSK from Hansoh Pharma in December 2023 for development outside Greater China. It is in global phase 1 development (NCT06551142) and is being studied in China in phase 1/2 trials across multiple solid tumors, including small cell lung cancer (SCLC) and sarcomas. In 2024–2025 it received FDA Breakthrough Therapy Designation (BTD) for relapsed/refractory extensive‑stage SCLC (August 20, 2024) and for late‑line relapsed/refractory osteosarcoma (January 7, 2025). China’s NMPA also granted Breakthrough‑Therapy designation for ES‑SCLC in November 2024. (gsk.com)

Mechanism of action

GSK5764227/HS‑20093 is a fully humanized anti–B7‑H3 ADC that delivers a DNA topoisomerase I inhibitor payload via intravenous dosing every 3 weeks. B7‑H3 (CD276) is broadly expressed across solid tumors with limited expression in normal tissues; the ADC internalizes upon target binding to release cytotoxic payload inside tumor cells. (gsk.com)

Clinical development

• Global: First‑in‑human, multi‑part phase 1 study sponsored by GSK (NCT06551142) is recruiting, including monotherapy dose escalation/expansion and combination cohorts with chemotherapy and immunotherapy. (cdek.pharmacy.purdue.edu)
• China: ARTEMIS‑001 (phase 1, NCT05276609) in advanced solid tumors; ARTEMIS‑002 (phase 2, NCT05830123) in relapsed/refractory osteosarcoma and other sarcomas. (cdek.pharmacy.purdue.edu)

Efficacy

Small cell lung cancer (ES‑SCLC), relapsed/refractory
- Phase 1 ARTEMIS‑001 expansion (randomized to 8 vs 10 mg/kg Q3W): as of June 30, 2024, overall response rate (ORR) was 61.3% (n=31) at 8 mg/kg and 50.0% (n=22) at 10 mg/kg; median PFS 5.9 and 7.3 months, respectively. Responses were observed regardless of B7‑H3 expression in the program. These results were presented at WCLC 2024 and ASCO 2024 (abstract 8093). (hspharm.com)

• Earlier dose‑escalation (through Dec 20, 2022): among 40 response‑evaluable patients across tumors, ORR was 35% with disease control rate (DCR) 85%; in a nine‑patient SCLC subset, ORR was 77.8%. (ascopubs.org)

Osteosarcoma and other sarcomas
- Phase 2 ARTEMIS‑002 (ASCO 2024, abstract 11507): in osteosarcoma randomized to 8 vs 12 mg/kg, ORR at 12 mg/kg was 20.0%; DCR 100% (10/10) at 12 mg/kg and 81.8% (9/11) at 8 mg/kg; median PFS not yet mature at data cutoff. In “other sarcomas” (single‑arm 12 mg/kg), ORR 25% and median PFS 7.1 months (interim). (ascopubs.org)

Notes: GSK reported FDA BTD based on preliminary clinical evidence in ES‑SCLC (Aug 2024) and in osteosarcoma (Jan 2025). (gsk.com)

Safety

Across early studies, the most frequent treatment‑emergent or treatment‑related grade ≥3 adverse events are hematologic, including neutropenia, leukopenia, anemia, lymphopenia, and thrombocytopenia. In ARTEMIS‑001 dose escalation, the maximum tolerated dose was 12 mg/kg; dose‑limiting toxicities occurred at 12–16 mg/kg. Notably, interstitial lung disease was not reported in the 2023 dose‑escalation abstract. Safety in expansion cohorts was described as consistent with earlier reports. (ascopubs.org)

Further reading

• ASCO 2023 phase 1 abstract (ARTEMIS‑001, dose escalation): https://ascopubs.org/doi/abs/10.1200/JCO.2023.41.16_suppl.3017 (ascopubs.org)
• ASCO 2024 abstract (ARTEMIS‑001 SCLC expansion, 8 vs 10 mg/kg): via Ovid listing https://www.ovid.com/journals/jclon/abstract/10.1200/jco.2024.42.16_suppl.8093 (ovid.com)
• WCLC 2024 update (company summary of ARTEMIS‑001 SCLC cohort): https://www.hspharm.com/news/news-detail-513214.htm (hspharm.com)
• ASCO 2024 abstract (ARTEMIS‑002 osteosarcoma): https://ascopubs.org/doi/abs/10.1200/JCO.2024.42.16_suppl.11507 (ascopubs.org)
• FDA BTD (ES‑SCLC): https://www.gsk.com/en-gb/media/press-releases/gsk-receives-us-fda-breakthrough-therapy-designation/ (gsk.com)
• FDA BTD (osteosarcoma): https://www.gsk.com/en-gb/media/press-releases/gsk-b7-h3-targeted-antibody-drug-conjugate-gsk227-receives-us-fda-breakthrough-therapy-designation-in-late-line-relapsed-or-refractory-osteosarcoma/ (gsk.com)
• NMPA Breakthrough‑Therapy designation (ES‑SCLC): https://www.hspharm.com/news/news-detail-513241.htm (hspharm.com)
• GSK–Hansoh license announcement (mechanism and program scope): https://www.gsk.com/en-gb/media/press-releases/gsk-enters-exclusive-license-agreement-with-hansoh-for-hs-20093/ (gsk.com)
• Global phase 1 trial record (NCT06551142): https://cdek.pharmacy.purdue.edu/trial/NCT06551142/ (cdek.pharmacy.purdue.edu)
• China phase 1 and phase 2 trial records (NCT05276609; NCT05830123): https://cdek.pharmacy.purdue.edu/trial/NCT05276609/ and https://cdek.pharmacy.purdue.edu/trial/NCT05830123/ (cdek.pharmacy.purdue.edu)

Disclaimer: Findings are from early‑phase studies and meeting abstracts; efficacy and safety profiles remain investigational and may evolve with ongoing trials. (ovid.com)

Last updated: Oct 2025