By Fineline Cube Shanghai Fosun Pharmaceutical (Group) Co., Ltd. (SHA: 600196, HKG: 2196) announced that HLX316, a novel first-in-class sialidase heterodimer targeting B7-H3, has received NMPA clinical trial approval for the treatment of advanced/metastatic solid tumors. The sialidase-Fc fusion protein, developed by fusing a B7-H3-targeting heavy-chain-only antibody variable region (VHH) with a licensed-in sialidase bifunctional fusion protein, represents Fosun Pharma’s innovation pivot into next-generation immuno-oncology modalities beyond its established biosimilar and PD-1 franchise.
Regulatory Milestone
| Item | Detail |
|---|---|
| Agency | NMPA (China) |
| Approval Type | Clinical trial authorization (IND) |
| Product | HLX316 |
| Drug Class | First-in-class sialidase heterodimer (sialidase-Fc fusion protein) |
| Target | B7-H3 (CD276) – immune checkpoint and tumor-associated antigen |
| Format | VHH (heavy-chain-only antibody) fused to sialidase + Fc domain |
| Indication | Advanced/metastatic solid tumors |
| Developer | Shanghai Fosun Pharmaceutical (SHA: 600196, HKG: 2196) |
| Approval Date | 9 Mar 2026 |
Drug Profile & Mechanism
| Attribute | HLX316 Specification |
|---|---|
| Architecture | Sialidase-Fc fusion protein heterodimer |
| Targeting Domain | B7-H3-specific VHH (heavy-chain-only antibody variable region) |
| Effector Domain | Sialidase enzyme (licensed-in bifunctional fusion) |
| Mechanism | • Desialylation: Removes sialic acid from tumor cell glycocalyx • Immune Activation: Unmasks tumor antigens; enhances NK cell and T-cell recognition • B7-H3 Blockade: Checkpoint inhibition via B7-H3 targeting |
| Innovation Class | First-in-class (no approved sialidase-targeting cancer therapeutics globally) |
Scientific Rationale:
- B7-H3 Overexpression: Highly expressed in lung, prostate, breast, and pediatric cancers; associated with poor prognosis and immune evasion
- Sialic Acid Shield: Tumor cells use hypersialylation to evade immune surveillance; enzymatic removal restores immune recognition
- Dual Mechanism: B7-H3 blockade + desialylation provides complementary immune activation pathways
Strategic Context & Competitive Landscape
| Factor | Market Implication |
|---|---|
| B7-H3 Target Validation | Multiple ADCs (DS-7300, MGC018) and CAR-Ts in Phase II/III; sialidase approach novel |
| Sialidase Modality | No approved sialidase cancer therapeutics; Palleon Pharma (sialidase-Fc) and other biotechs in early development |
| Fosun Innovation Pivot | HLX316 demonstrates R&D capabilities beyond biosimilars; positions as China innovator in immuno-oncology |
| Licensed Component | Sialidase technology in-licensed; VHH platform proprietary; balanced IP strategy |
| Global Potential | First-in-class status supports U.S./EU IND filing; orphan indication potential in B7-H3-high pediatric tumors |
Competitive Dynamics
| Competitor | Product | Mechanism | Status | HLX316 Differentiation |
|---|---|---|---|---|
| Daiichi Sankyo | DS-7300 (ifinatamab deruxtecan) | B7-H3 ADC | Phase II | Sialidase enzymatic activity + checkpoint blockade vs. cytotoxic payload |
| MacroGenics | Enoblituzumab | B7-H3 mAb | Phase II | Dual-action desialylation + B7-H3 targeting |
| Palleon Pharma | E-602 (sialidase-Fc) | Pan-tumor desialylation | Phase I | HLX316 adds B7-H3 targeting for tumor-specific delivery |
| Fosun Pharma | HLX316 | B7-H3-targeted sialidase heterodimer | Phase I-ready | First-in-class bifunctional; China-developed global asset |
Development Outlook
| Phase | Timeline | Objectives |
|---|---|---|
| Phase I | 2026-2027 | Safety, tolerability, MTD; biomarker validation (sialylation levels, B7-H3 expression) |
| Phase II | 2027-2029 | Expansion in B7-H3-high indications (lung, prostate, neuroblastoma); combination with PD-1 |
| Global Expansion | 2028-2030 | U.S./EU IND; potential Fast Track for pediatric solid tumors |
| Partnering | Ongoing | Licensing discussions for ex-China rights anticipated given first-in-class status |
Forward‑Looking Statements
This brief contains forward‑looking statements regarding clinical development timelines, first-in-class positioning, and competitive differentiation for HLX316. Actual results may differ due to novelty of sialidase mechanism, manufacturing complexity, and competitive dynamics in B7-H3-targeted oncology.-Fineline Info & Tech