By Fineline Cube Youcare Pharmaceutical (SHA: 688658) announced that YKYY033 injection has received approval from the US Food and Drug Administration (FDA) to conduct clinical trials for the prevention and treatment of arterial and venous thrombosis, advancing the company’s siRNA candidate against coagulation factor XI (FXI) into US clinical development.
Regulatory Milestone
| Item | Detail |
|---|---|
| Company | Youcare Pharmaceutical (SHA: 688658) |
| Agency | US FDA |
| Approval Type | Clinical trial approval |
| Drug | YKYY033 injection |
| Indication | Prevention and treatment of arterial and venous thrombosis |
| Approval Date | 13 Aug 2026 |
| China Status | Phase 1 study approved by NMPA; currently progressing |
Drug Profile – YKYY033
- Modality: Chemically synthesized double-stranded siRNA drug conjugated with an N-acetylgalactosamine (GalNAc) ligand
- Mechanism of Action: Silences messenger RNA (mRNA) transcribed from the coagulation factor XI (FXI) gene through RNA interference, inhibiting FXI protein production at the source
- Target Rationale: FXI inhibition is a leading strategy for anticoagulants that aim to prevent thrombosis without increasing bleeding risk
Preclinical Profile
| Parameter | Result |
|---|---|
| FXI Suppression | Significantly reduces FXI protein levels and activity across various animal models |
| Coagulation Effect | Efficiently and durably prolongs APTT without affecting prothrombin time (PT) — demonstrating specific inhibition of the intrinsic coagulation pathway |
| Antithrombotic Efficacy | Significant antithrombotic efficacy in thrombus models without increasing bleeding risk |
| Toxicology | Repeat-dose toxicity studies indicate a favorable safety and tolerability profile |
Market Impact & Outlook
- Dual-Market Clinical Pathway: With the FDA clearance joining an NMPA-approved Phase 1 study already progressing in China, YKYY033 is positioned for parallel US-China development — a structure that broadens partnership and licensing optionality.
- FXI: A Crowded but Validated Battleground: Factor XI has become one of anticoagulation’s most sought-after targets as the field pursues safer alternatives to factor Xa and thrombin inhibitors, which carry inherent bleeding liability.
- siRNA Differentiation: A GalNAc-conjugated siRNA approach to FXI offers the potential for durable, infrequently dosed anticoagulation, distinguishing YKYY033 from small-molecule and antibody FXI candidates in development.
- Next Steps: Trial design, dosing schedules, and timelines for first patient dosing in the US were not disclosed.
Forward‑Looking Statements
This brief contains forward-looking statements regarding the clinical development potential of YKYY033. Actual results may differ due to risks including clinical progress, safety outcomes, and competitive dynamics in anticoagulation therapeutics.-Fineline Info & Tech