By Fineline Cube Clover Biopharmaceuticals Ltd. (HKG: 2197) announced the completion of subject enrollment in a Phase II clinical trial in Australia for its novel respiratory combination vaccine candidates, SCB 1022 and SCB 1033. Both candidates leverage Clover’s proprietary Trimer-Tag® protein trimerization platform to present pre-fusion F (Pre-F) trimeric antigens—a conformation proven to elicit potent neutralizing antibodies against respiratory viruses. The study targets older adults aged 60–85, a high-risk population for severe lower respiratory tract infections, with topline results expected in Q3 2026.
Clinical Trial Design
| Feature | Detail |
|---|---|
| Phase | II |
| Design | Randomized, observer-blind, multi-center |
| Location | Australia |
| Population | 420 older adults (60–85 years) |
| Arms | SCB 1022 / SCB 1033 / Placebo |
| Primary Endpoints | Safety, reactogenicity, immunogenicity |
| Expected Readout | Q3 2026 |
The trial represents one of the first mid-stage studies evaluating multi-virus respiratory vaccines in an elderly cohort outside of influenza or RSV monovalent programs.
Vaccine Candidates Overview
SCB 1022
- Targets: Respiratory syncytial virus (RSV) + Human metapneumovirus (hMPV)
- Antigen Format: Pre-F trimeric subunits fused to Trimer-Tag® for stability and immunogenicity
SCB 1033
- Targets: RSV + hMPV + Parainfluenza virus type 3 (PIV3)
- Differentiation: First publicly disclosed trivalent non-influenza respiratory vaccine candidate using native-like Pre-F trimers
All antigens are produced via mammalian cell expression, ensuring proper glycosylation and conformational fidelity—a key advantage over nanoparticle or mRNA platforms for fusion protein vaccines.
Platform Advantage: Trimer-Tag® Technology
- Mechanism: Fuses target antigens to a collagen-derived trimerization domain, forcing stable homotrimer formation
- Proven Track Record: Underpinned Clover’s RSVPreF3 OA vaccine, which demonstrated >80% efficacy in Phase III elderly trials
- Manufacturing Scalability: Uses standard bioreactor processes compatible with global CMO infrastructure
By presenting antigens in their native pre-fusion conformation, Trimer-Tag® vaccines mimic viral surface structures more accurately, driving higher-quality immune responses.
Strategic Significance
- Unmet Need: No approved vaccines exist for hMPV or PIV3, despite causing ~20% of pediatric and elderly hospitalizations for bronchiolitis and pneumonia
- Market Opportunity: Combined annual burden of RSV, hMPV, and PIV3 exceeds 50 million cases globally in at-risk populations
- Commercial Pathway: Success could position Clover as a leader in next-generation respiratory vaccines, complementing its existing RSV program and enabling combination strategies with seasonal flu shots
Positive data may trigger partnership interest from global vaccine majors seeking to expand beyond influenza and SARS-CoV-2.
Forward‑Looking Statements
This brief contains forward-looking statements regarding clinical development timelines, immunogenicity outcomes, and strategic opportunities. Actual results may differ due to trial variability, regulatory feedback, and competitive dynamics.-Fineline Info & Tech