Fitusiran
1711.0 g/mol, C₇₈H₁₃₉N₁₁O₃₀

FDA APPROVED 3/28/2025, Qfitlia, To prevent or reduce the frequency of bleeding episodes in hemophilia A or B
Press Release

• CAS 1499251-18-1
• EX-A12034
• DA-53206
• N-[1,3-Bis[3-[3-[5-[(2R,3R,4R,5R,6R)-3-acetamido-4,5-dihydroxy-6-(hydroxymethyl)oxan-2-yl]oxypentanoylamino]propylamino]-3-oxopropoxy]-2-[[3-[3-[5-[(2R,3R,4R,5R,6R)-3-acetamido-4,5-dihydroxy-6-(hydroxymethyl)oxan-2-yl]oxypentanoylamino]propylamino]-3-oxopropoxy]methyl]propan-2-yl]-12-[(2R,4R)-4-hydroxy-2-methylpyrrolidin-1-yl]-12-oxododecanamide

Fitusiran Sodium

43 Sodium salt of duplex of [(2S,4R)-1-{1-[(2-acetamido-2-deoxy-β-D-galactopyranosyl)oxy]-16,16-bis({3-[(3-{5-[(2-acetamido-2-deoxy-β-D-galactopyranosyl)oxy]pentanamido}propyl)amino]-3-oxopropoxy}methyl)-5,11,18-trioxo-14-oxa-6,10,17-triazanonacosan-29-oyl}-4-hydroxypyrrolidin-2-yl]methyl hydrogen all–P–ambo-2′-deoxy-2′-fluoro-P-thioguanylyl-(3’→5′)-2′-O-methyl-P-thioguanylyl-(3’→5′)-2′-deoxy-2′-fluorouridylyl-(3’→5′)-2′-O-methyluridylyl-(3’→5′)-2′-deoxy-2′-fluoroadenylyl-(3’→5′)-2′-O-methyladenylyl-(3’→5′)-2′-deoxy-2′-fluorocytidylyl-(3’→5′)-2′-O-methyladenylyl-(3’→5′)-2′-deoxy-2′-fluorocytidylyl-(3’→5′)-2′-deoxy-2′-fluorocytidylyl-(3’→5′)-2′-deoxy-2′-fluoroadenylyl-(3’→5′)-2′-O-methyluridylyl-(3’→5′)-2′-deoxy-2′-fluorouridylyl-(3’→5′)-2′-O-methyluridylyl-(3’→5′)-2′-deoxy-2′-fluoroadenylyl-(3’→5′)-2′-O-methylcytidylyl-(3’→5′)-2′-deoxy-2′-fluorouridylyl-(3’→5′)-2′-O-methyluridylyl-(3’→5′)-2′-deoxy-2′-fluorocytidylyl-(3’→5′)-2′-O-methyladenylyl-(3’→5′)-2′-deoxy-2′-fluoro-3′-adenylate and all–P–ambo-2′-O-methyl-P-thiouridylyl-(3’→5′)-2′-deoxy-2′-fluoro-P-thiouridylyl-(3’→5′)-2′-O-methylguanylyl-(3’→5′)-2′-deoxy-2′-fluoroadenylyl-(3’→5′)-2′-O-methyladenylyl-(3’→5′)-2′-deoxy-2′-fluoroguanylyl-(3’→5′)-2′-O-methyluridylyl-(3’→5′)-2′-deoxy-2′-fluoroadenylyl-(3’→5′)-2′-O-methyladenylyl-(3’→5′)-2′-deoxy-2′-fluoroadenylyl-(3’→5′)-2′-O-methyluridylyl-(3’→5′)-2′-O-methylguanylyl-(3’→5′)-2′-O-methylguanylyl-(3’→5′)-2′-deoxy-2′-fluorouridylyl-(3’→5′)-2′-O-methylguanylyl-(3’→5′)-2′-deoxy-2′-fluorouridylyl-(3’→5′)-2′-O-methyluridylyl-(3’→5′)-2′-deoxy-2′-fluoroadenylyl-(3’→5′)-2′-O-methyladenylyl-(3’→5′)-2′-deoxy-2′-fluorocytidylyl-(3’→5′)-2′-O-methyl-P-thiocytidylyl-(3’→5′)-2′-O-methyl-P-thioadenylyl-(3’→5′)-2′-O-methylguanosine

C₅₂₀H₆₃₆F₂₁N₁₇₅Na₄₃O₃₀₉P₄₃S₆  : 17193.39
[1609016-97-8]

Fitusiran, sold under the brand name Qfitlia, is a medication used for the treatment of hemophilia.^[1] It is an antithrombin-directed small interfering ribonucleic acid.^[1] It is given by subcutaneous injection.^[1] Fitusiran reduces the amount of a protein called antithrombin.^[2]

The most common side effects include viral infection, common cold symptoms (nasopharyngitis) and bacterial infection.^[2]

Fitusiran was approved for medical use in the United States in March 2025.^[2]

PATENT

https://patents.google.com/patent/WO2023240199A2/en

Medical uses

Fitusiran is indicated for routine prophylaxis to prevent or reduce the frequency of bleeding episodes in people aged twelve years of age and older with hemophilia A or hemophilia B, with or without factor VIII or IX inhibitors (neutralizing antibodies).^[1][2]

Adverse effects

The US Food and Drug Administration prescription label for fitusiran contains a boxed warning for thrombotic events (blood clotting) and gallbladder disease (with some recipients requiring gallbladder removal).^[2] The label also has a warning about liver toxicity and the need to monitor liver blood tests at baseline and then monthly for at least six months after initiating treatment with fitusiran or after a dose increase of fitusiran.^[2]

History

The efficacy and safety of fitusiran were assessed in two multicenter, randomized clinical trials which enrolled a total of 177 adult and pediatric male participants with either hemophilia A or hemophilia B.^[2] In one study, participants had inhibitory antibodies to coagulation factor VIII or coagulation factor IX and previously received on-demand treatment with medicines known as “bypassing agents” for bleeding.^[2] In the second study, participants did not have inhibitory antibodies to coagulation factor VIII or coagulation factor IX and previously received on-demand treatment with clotting factor concentrates.^[2] In the two randomized trials, participants received either a fixed dose of fitusiran monthly or their usual on-demand treatment (bypassing agents or clotting factor concentrates) as needed for nine months.^[2] The fixed dose of fitusiran is not approved because it led to excessive clotting in some participants.^[2]

The US Food and Drug Administration (FDA) granted the application for fitusiran orphan drug and fast track designations. The FDA granted the approval of Qfitlia to Sanofi.

Society and culture

Legal status

Fitusiran was approved for medical use in the United States in March 2025.^[2][3]

Names

Fitusiran is the international nonproprietary name.^[4]

Fitusiran is sold under the brand name Qfitlia.^[1][2]

References

^ Jump up to:^{a b c d e f} “Qfitlia- fitusiran injection, solution”. DailyMed. 26 March 2025. Retrieved 2 April 2025.

1. ^ Jump up to:^{a b c d e f g h i j k l m} “FDA Approves Novel Treatment for Hemophilia A or B, with or without Factor Inhibitors”. U.S. Food and Drug Administration. 28 March 2025. Retrieved 29 March 2025.  This article incorporates text from this source, which is in the public domain.
2. ^ “Qfitlia approved as the first therapy in the US to treat hemophilia A or B with or without inhibitors”. Sanofi (Press release). 28 March 2025. Retrieved 29 March 2025.
3. ^ World Health Organization (2016). “International nonproprietary names for pharmaceutical substances (INN): recommended INN: list 75”. WHO Drug Information. 30 (1). hdl:10665/331046.

Further reading

Srivastava A, Rangarajan S, Kavakli K, Klamroth R, Kenet G, Khoo L, et al. (May 2023). “Fitusiran prophylaxis in people with severe haemophilia A or haemophilia B without inhibitors (ATLAS-A/B): a multicentre, open-label, randomised, phase 3 trial”. The Lancet. Haematology. 10 (5): e322 – e332. doi:10.1016/S2352-3026(23)00037-6. PMID 37003278.

• Young G, Kavakli K, Klamroth R, Matsushita T, Peyvandi F, Pipe SW, et al. (March 2025). “Safety and efficacy of a fitusiran antithrombin-based dose regimen in people with hemophilia A or B: the ATLAS-OLE study”. Blood. doi:10.1182/blood.2024027008. PMID 40053895.
• Young G, Srivastava A, Kavakli K, Ross C, Sathar J, You CW, et al. (April 2023). “Efficacy and safety of fitusiran prophylaxis in people with haemophilia A or haemophilia B with inhibitors (ATLAS-INH): a multicentre, open-label, randomised phase 3 trial”. Lancet (London, England). 401 (10386): 1427–1437. doi:10.1016/S0140-6736(23)00284-2. PMID 37003287.

External links

• Clinical trial number NCT03417102 for “A Study of Fitusiran (ALN-AT3SC) in Severe Hemophilia A and B Patients With Inhibitors (ATLAS-INH)” at ClinicalTrials.gov
• Clinical trial number NCT03417245 for “A Study of Fitusiran (ALN-AT3SC) in Severe Hemophilia A and B Patients Without Inhibitors” at ClinicalTrials.gov
• Clinical trial number NCT03754790 for “Long-term Safety and Efficacy Study of Fitusiran in Patients With Hemophilia A or B, With or Without Inhibitory Antibodies to Factor VIII or IX (ATLAS-OLE)” at ClinicalTrials.gov

////////Fitusiran, Qfitlia, FDA 2025, APPROVALS 2025, EX-A12034, DA-53206