By Fineline Cube Shanghai Henlius Biotech Inc. (HKG: 2696) announced that China’s National Medical Products Administration (NMPA) has granted approval to initiate a Phase I clinical study for HLX3902, a novel trispecific antibody (TsAb) T-cell engager, in patients with advanced solid tumors. The investigational therapy simultaneously targets STEAP1, CD3, and CD28, representing an innovative approach to enhancing T-cell-mediated tumor cell lysis.
Regulatory Milestone
| Item | Detail |
|---|---|
| Agency | NMPA (China) |
| Approval Type | Clinical trial authorization – Phase I |
| Product | HLX3902 (trispecific antibody T-cell engager) |
| Indication | Advanced solid tumors, including metastatic castration-resistant prostate cancer (mCRPC) |
| Approval Date | June 2026 |
| Previous Approvals | Australia clinical trial clearance (May 2026) |
Drug Profile & Mechanism of Action
- Molecule: Trispecific antibody (TsAb) T-cell engager
- Targets: STEAP1 (tumor antigen), CD3 (T-cell receptor complex), and CD28 (T-cell co-stimulatory receptor)
- Innovation: First-in-class approach that simultaneously optimizes both signal 1 (CD3) and signal 2 (CD28) for comprehensive T-cell activation
- Mechanism: Enhances T-cell activation, proliferation, and survival while directing cytotoxic activity specifically against STEAP1-expressing tumor cells
- Therapeutic Focus: Metastatic castration-resistant prostate cancer (mCRPC) and other STEAP1-positive advanced solid tumors
Preclinical Evidence
| Parameter | Result |
|---|---|
| Anti-tumor Efficacy | Favorable tumor growth inhibition in multiple solid tumor models |
| Safety Profile | Manageable toxicity profile with no dose-limiting toxicities observed |
| T-cell Activation | Enhanced proliferation and cytokine production compared to bispecific controls |
| Target Specificity | Selective binding to STEAP1-expressing cells with minimal off-target effects |
Preclinical studies demonstrated that HLX3902 achieves superior anti-tumor activity through its dual-signal optimization strategy, addressing limitations of current T-cell engagers that rely solely on CD3 activation without co-stimulatory support.
Market Impact & Strategic Context
- Prostate Cancer Landscape: mCRPC represents a significant unmet medical need with limited treatment options after progression on standard therapies
- STEAP1 Target: Expressed in >90% of prostate cancers and multiple other solid tumors, providing broad therapeutic potential
- Competitive Differentiation: Unlike approved bispecific antibodies, HLX3902’s trispecific design incorporating CD28 co-stimulation may overcome T-cell exhaustion and improve durability of response
- Global Development Strategy: Dual regulatory pathway through Australia and China enables accelerated clinical development and potential global registration
- Henlius Portfolio: Complements the company’s existing oncology pipeline and reinforces its position as a leader in innovative biologics development in China
The Phase I trial will evaluate safety, tolerability, pharmacokinetics, and preliminary efficacy of HLX3902 in patients with advanced solid tumors, with initial focus on mCRPC populations.
Forward-Looking Statements
This brief contains forward-looking statements regarding clinical development timelines, regulatory approvals, and therapeutic potential of HLX3902. Actual results may differ due to risks including clinical trial outcomes, regulatory decisions, and competitive developments.-Fineline Info & Tech