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Fitusiran (SAR439774)
Fitusiran is an RNA interference (RNAi) therapeutic that silences antithrombin (AT) messenger RNA to reduce antithrombin levels and enhance the intrinsic coagulation pathway, thereby increasing thrombin generation in patients with hemophilia.
Fitusiran is an RNA interference (RNAi) therapeutic that silences antithrombin (AT) messenger RNA to reduce antithrombin levels and enhance the intrinsic coagulation pathway, thereby increasing thrombin generation in patients with hemophilia. Used for Hemophilia A prophylaxis (including patients with inhibitors), Hemophilia B prophylaxis (including patients with inhibitors).
At a glance
| Generic name | Fitusiran (SAR439774) |
|---|---|
| Also known as | SAR439774, Qfitlia® |
| Sponsor | Genzyme, a Sanofi Company |
| Drug class | RNA interference (RNAi) therapeutic; antithrombin silencer |
| Target | Antithrombin (AT) mRNA |
| Modality | Small molecule |
| Therapeutic area | Hematology |
| Phase | FDA-approved |
Mechanism of action
Fitusiran uses small interfering RNA (siRNA) chemistry to target and degrade antithrombin mRNA in hepatocytes, leading to decreased antithrombin protein levels. By reducing this natural anticoagulant, the drug compensates for deficient clotting factors in hemophilia patients, allowing residual factor activity to generate sufficient thrombin for hemostasis. This mechanism enables prophylaxis against bleeding in both hemophilia A and B, including patients with inhibitors.
Approved indications
- Hemophilia A prophylaxis (including patients with inhibitors)
- Hemophilia B prophylaxis (including patients with inhibitors)
Common side effects
- Injection site reactions
- Elevated liver enzymes (transaminases)
- Thrombotic events
- Headache
Key clinical trials
- A Study to Investigate the Efficacy and Safety of Fitusiran Prophylaxis in Male Participants Aged 1 to Less Than 12 Years With Hemophilia A or B (PHASE3)
- A Study to Test a Medicine (Fitusiran) for Preventing Bleeds in People With Severe Hemophilia Who Previously Received Preventive Treatment With Emicizumab (PHASE4)
- Fitusiran Prophylaxis in Male Pediatric Subjects Aged 1 to Less Than 12 Years With Hemophilia A or B (PHASE3)
- An Open-label Extension Study of an Investigational Drug, Fitusiran, in Patients With Moderate or Severe Hemophilia A or B (PHASE1, PHASE2)
Primary sources
Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.
| Source | Used for |
|---|---|
| ClinicalTrials.gov | Trial enrolment, design, endpoints, results |
Competitive intelligence
For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:
- Fitusiran (SAR439774) CI brief — competitive landscape report
- Fitusiran (SAR439774) updates RSS · CI watch RSS
- Genzyme, a Sanofi Company portfolio CI