Shanghai Henlius Biotech, Inc. (Henlius) has commenced patient dosing in a first-in-human Phase 1 clinical study of HLX316, a B7-H3-targeting sialidase Fc fusion protein, in mainland China. The trial focuses on patients with advanced or metastatic solid tumours and excludes Hong Kong, Macau and Taiwan.
The open-label study is structured in two parts. Phase 1a features dose escalation and backfill across five weekly dose levels—1.0, 3.0, 10.0, 20.0 and 30.0 mg/kg. The 1.0 mg/kg cohort uses an accelerated titration design, while the remaining cohorts follow a traditional 3+3 escalation. Phase 1b will expand at dose level(s) selected from Phase 1a based on safety and preliminary efficacy. Primary endpoints include incidence of dose-limiting toxicities, determination of the maximum tolerated dose and recommended Phase 2 dose, and investigator-assessed objective response rate.
HLX316 combines an engineered human sialidase Neu2 fused to an IgG1 Fc region with a heavy-chain-only antibody variable domain (VHH) that binds B7-H3, also fused to an IgG1 Fc. The molecule aims to enzymatically remove immunosuppressive sialylated glycans from B7-H3-expressing tumours, enhancing anti-tumour immune responses without broad systemic activation. Pre-clinical models showed potent antigen-directed desialylation and tumour growth inhibition. The National Medical Products Administration approved the investigational new drug application in March 2026.
No B7-H3-targeting sialidase Fc fusion protein has yet received marketing approval worldwide, positioning HLX316 as a potential first-in-class therapy.
Henlius emphasised that successful development and commercialisation are not guaranteed, and shareholders should exercise caution when trading the company’s shares.
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