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Introduction

AHFS Class:

Generic Name(s):

Fitusiran is an antithrombin-directed small interfering ribonucleic acid.1

Uses

Hemophilia A or B

Fitusiran is used for routine prophylaxis to prevent or reduce bleeding episodes in adults and pediatric patients 12 years of age with hemophilia A or hemophilia B with or without factor VIII or IX inhibitors.1 Fitusiran has been designated an orphan drug by FDA for the treatment of hemophilia A and hemophilia B with and without inhibitors.2

The efficacy and safety of fitusiran for the treatment of hemophilia A or B with or without inhibitors in adults and pediatric patients 12 years of age have been established in phase 3 studies including ATLAS-INH (patients with inhibitors) and ATLAS-A/B (patients without inhibitors); the studies showed superiority in annualized bleeding rates with fitusiran compared with control (on-demand bypassing agents or clotting factor concentrates).1,  3,  4,  5,  6 Patients from these studies entered a long-term open-label extension (OLE) trial, ATLAS-OLE.1,  6,  7

The ATLASINH and ATLASA/B studies evaluated a fixed 80mg monthly dose of fitusiran.1,  3,  4,  5 Due to thrombotic events, a doseadjustment regimen targeting antithrombin (AT) activity of 15-35% was introduced in the single-arm ATLASOLE extension.1,  3,  4,  5 Because the doseadjustment regimen began as the parent trials were ending, efficacy was assessed by comparing ATLASOLE data with control data from ATLASINH and ATLASA/B, using intenttotreat analyses that preserved parentstudy randomization.1,  3

Hemophilia A or B with Factor VIII or IX Inhibitors

The efficacy and safety of fitusiran in patients with hemophilia A or B with inhibitors were evaluated in the phase 3 ATLASINH trial.1,  3,  4 This randomized, multicenter, openlabel study enrolled 57 male patients 12 years of age with congenital hemophilia and inhibitory antibodies to factor VIII or IX who were previously treated with ondemand bypassing agents.1,  3,  4 A total of 57 patients were randomized 2:1 to receive fitusiran 80 mg subcutaneously once monthly or ondemand bypassing agents for 9 months.1,  3,  4 Baseline characteristics included 45 patients with hemophilia A and 12 patients with hemophilia B; the mean age of patients was 28.4 years and 17.5% were between 12-17 years of age.1,  3,  4 Most patients were Asian (68.4%) or White (28.1%); 5.3% of patients were Hispanic or Latino.1,  3,  4 After completing the parent trials, patients transitioned into the longterm, openlabel extension (ATLASOLE), which included 59 patients with inhibitors.1,  3,  6 During the extension, the protocol shifted from a fixed 80-mg dose to a doseadjustment regimen targeting AT activity of 15-35%.1,  3,  6 The doseadjustment period lasted 6 months, beginning with 50 mg every 2 months and modifying to 50 mg monthly, 20 mg monthly, or 20 mg every 2 months as guided by AT levels; treatment was discontinued if AT activity fell below 15%.1,  3,  6 During the subsequent 7month efficacy evaluation, patients with inhibitors achieved a median annualized bleeding rate of 1.9 (interquartile range [IQR] 0-5.6).1,  3,  6

When comparing ATLASOLE results with the control group from the ATLASINH study, fitusiran using the doseadjustment regimen significantly reduced bleeding in patients 12 years of age with hemophilia A or B with inhibitors compared with ondemand bypassing agents.1,  3 The median annualized bleed rate for all treated bleeds was 5.1 with fitusiran versus 19.1 with bypassing agents, a significant 73% reduction.1,  3 For treated spontaneous bleeds, the annualized bleeding rate was 3.1 with fitusiran versus 17.1 with bypassing agents, an 82% reduction.1,  3 For treated joint bleeds, the annualized bleeding rate was 4.0 with fitusiran versus 14.4 with bypassing agents, a 73% reduction.1,  3

Hemophilia A or B without Inhibitors

Fitusiran was studied in patients with hemophilia A or B without inhibitors in the phase 3 ATLASA/B trial.1,  3,  5 This randomized, multicenter, openlabel study enrolled 120 male patients 12 years of age with congenital hemophilia without inhibitors who were previously treated with ondemand clotting factor concentrates.1,  3,  5 A total of 120 patients were randomized 2:1 to receive fitusiran 80 mg subcutaneously once monthly or ondemand clotting factor concentrates for 9 months.1,  3,  5

Baseline characteristics included 93 patients with hemophilia A and 27 patients with hemophilia B; the mean age of patients was 33.8 years and 11.7% were between 12-17 years of age.1,  3,  5 Most patients were Asian (59.2%) or White (37.5%); 3.3% of patients were Hispanic or Latino.1,  3,  5 After completion of the parent trial, patients entered the ATLASOLE extension and transitioned to a doseadjustment regimen targeting AT activity of 15-35%.1,  3,  6 During the 7month efficacy evaluation following dose adjustment, patients without inhibitors achieved a median annualized bleeding rate of 3.8 (IQR 0-11.2).1,  3,  5

When comparing ATLASOLE results with the control group from ATLASA/B, fitusiran using the doseadjustment regimen significantly reduced bleeding in patients 12 years of age with hemophilia A or B without inhibitors compared with ondemand clotting factor concentrate.1,  3 The annualized bleed rate for all treated bleeds was 9.0 with fitusiran versus 31.4 with clotting factor concentrates, a significant 71% reduction.1,  3 For treated spontaneous bleeds, the annualized bleeding rate was 5.4 with fitusiran versus 21 with clotting factors, a 74% reduction.1,  3 For treated joint bleeds, the annualized bleeding rate was 6.2 with fitusiran versus 21.6 with clotting factors, a significant 71% reduction.1,  3

Clinical Perspective

Congenital hemophilia is a rare X-linked bleeding disorder caused by deficiencies in clotting factors (factor VIII in hemophilia A and factor IX in hemophilia B).1,  3,  8,  9 In hemophilia A, reduced endogenous factor VIII impairs coagulation, increasing the risk of bleeding into soft tissues, muscles, joints, and internal organs.3,  8,  9 In hemophilia B, a deficiency or dysfunction of factor IX leads to comparable bleeding risks and clinical manifestations.3,  8,  9

The clinical severity and frequency of bleeding episodes generally correlate with the degree of factor deficiency.8,  9 Patients with mild hemophilia have >5% of normal factor activity, moderate hemophilia 1-5%, and severe hemophilia <1% of normal factor activity.8,  9 A major complication in both types is the development of neutralizing antibodies (inhibitors) to clotting factor replacement therapy, occurring in approximately 30-35% of patients with hemophilia A and 5-15% with hemophilia B, making bleeding episodes more difficult to manage and increasing morbidity and mortality.3,  8,  9

The World Federation of Hemophilia (WFH) and the Medical and Scientific Advisory Council (MASAC) of the National Hemophilia Foundation published evidence-based guidelines on hemophilia management.8,  9 These guidelines recommend prophylactic therapy with clotting factor concentrates or non-factor replacement therapies (e.g., emicizumab) as the standard of care for patients with severe hemophilia A or B without inhibitors.8,  9 For patients with hemophilia B, prophylaxis typically involves factor IX concentrates, including extended half-life products that reduce the frequency of dosing.8,  9 Prophylaxis may also be considered for patients with mild or moderate hemophilia A or B based on bleeding risk and is ideally initiated before 3 years of age to prevent joint damage and recurrent bleeds.8,  9 Once initiated, prophylactic therapy is often continued indefinitely.8,  9

In patients with inhibitors, management is more complex.8,  9 For patients with hemophilia A with inhibitors, bypassing agents such as activated prothrombin complex concentrate (aPCC) or recombinant factor VIIa and emicizumab (a bispecific monoclonal antibody) have been used for prophylaxis; emicizumab may be preferred to factor therapy due to its efficacy, ease of use, and cost-effectiveness.8,  9 There is currently no widely used non-factor therapy for patients with hemophilia B with inhibitors and bypassing agents are routinely used.8,  9 MASAC recommends an individualized approach to the management of patients with inhibitors.9 Choice of treatment should be individualized based on factors such as type of inhibitor (low- or high-responding), current titer of inhibitor, prior treatment response, and available evidence.9 For patients with hemophilia A and high titer inhibitors, immune tolerance induction (ITI) may be the best option; experience with ITI is more limited in patients with hemophilia B with inhibitors.8,  9 Consultation with a hemophilia treatment center is strongly recommended when managing patients with hemophilia with inhibitors.8,  9 These guidelines do not address the use of fitusiran, as these guidelines were published prior to drug approval.8,  9

Dosage and Administration

General

Pretreatment Screening

Patient Monitoring

Dispensing and Administration Precautions

Other General Considerations

Administration

Administer fitusiran by subcutaneous injection only.1 Fitusiran is available as a 50 mg/0.5 mL (100 mg/mL) single-dose prefilled pen and a 20 mg/0.2 mL (100 mg/mL) single-dose vial.1

Subcutaneous Administration

Fitusiran should be used under the guidance of a healthcare provider; after receiving appropriate training, patients or caregivers may administer the drug if deemed appropriate.1 For patients 12-17 years of age, fitusiran should be administered by or under the supervision of an adult.1

Administer fitusiran by subcutaneous injection into the thigh or abdomen (avoiding 2 inches around the navel) or the outer area of the upper arm (if administered by a caregiver).1 Do not inject into tender, bruised, scarred, or damaged skin or into a vein.1

Use only clear, colorless to pale yellow solution; do not use if discolored, cloudy, contains particles, or is damaged.1

Store the 50 mg prefilled pen in the refrigerator (2-8°C) in the original carton to protect from light.1 May be stored once at room temperature (15-30°C) for 3 months within the labeled expiration date; discard after 3 months or at expiration, whichever comes first.1 Do not return to refrigeration after room temperature storage.1

Store the 20 mg vial in the refrigerator (2-8°C) or at room temperature (15-30°C) in the original carton to protect from light.1 Do not return to refrigeration after room temperature storage.1 Do not shake, heat, freeze, or expose to direct sunlight.1

Allow refrigerated fitusiran to warm to room temperature for 30 minutes before administration.1 Use a sterile 1 mL Luer Lock syringe with a 27gauge ½inch needle to withdraw the drug from vials.1

Dosage

Hemophilia A or B

The recommended initial dosage of fitusiran for routine prophylaxis of bleeding in adults and pediatric patients 12 years of age with hemophilia A or B is 50 mg once every 2 months by subcutaneous injection.1

Measure AT activity to guide subsequent dosing (see Dosage Modification section below).1

If a dose of fitusiran is missed, administer the dose as soon as possible, then resume the regular monthly or bimonthly schedule from the last dose.1

Dosage Modification

Measure AT activity using an FDA-cleared test at weeks 4, 12, 20, and 24 following the initial dose and after any dosage modification; adjust the dose and/or dosing interval of fitusiran accordingly to maintain AT activity between 15-35% (see Table 1).1

If AT activity <15%, reduce the dosage starting 3 months after the prior dosage.1

If AT activity >35% after 6 months or if the patient has not achieved adequate bleed control, consider dosage increase.1

The recommended AT monitoring schedule should be restarted after dosage reduction or escalation.1

Once target dosage identified based on AT activity 15-35%, measure AT activity annually and when clinically indicated.1

When therapy is discontinued, there is no need to continuing monitoring AT levels unless the patient is bleeding and treatment with clotting factor concentrates or bypassing agents is needed.1

Table 1. Dosage Modification Based on AT Activity Level1

Last Dosage Administered

Antithrombin Activity Level

Dosage Modification

50 mg every 2 months

<15%

20 mg every 2 months

50 mg every 2 months

15-35%

Continue current dosage

50 mg every 2 months

>35% after 6 months

50 mg every month

20 mg every 2 months

<15%

10 mg every 2 months

20 mg every 2 months

15-35%

Continue current dosage

20 mg every 2 months

>35% after 6 months

20 mg every month

10 mg every 2 months

<15%

Discontinue

10 mg every 2 months

15-35%

Continue current dosage

10 mg every 2 months

>35% after 6 months

10 mg every month

Breakthrough Bleed Management

If breakthrough bleeding requiring on-demand treatment with clotting factor concentrates or bypassing agents occurs during the first 7 days after the first fitusiran dose, manage the bleed using the patient's prior dosing regimen of the clotting factor concentrate or bypassing agent.1 If breakthrough bleeding occurs after 7 days from the first fitusiran dose, manage the bleed using reduced dosages of clotting factor concentrates or bypassing agents to minimize the risk of thrombotic events.1 The manufacturer provides guidelines for such reduced dosing in Table 2.1 Initially, the standard weight-based dose of these agents should be reduced and the dosing interval doubled.1 However, clinical judgment should be used to determine if higher doses, more frequent administration, or multiple repeat doses is needed.1 The combination of clotting factor concentrates or bypassing agents with antifibrinolytic agents has not been studied.1

Table 2. Breakthrough Bleed Management While Treated with Fitusiran1

Factor VIII

Factor IX (standard half-life)

Factor IX (extended half-life)

Activated Prothrombin Complex Concentrate (aPCC)

Activated Recombinant Factor VII (rFVIIa)

Recommended dose

10 international units (IU)/kg (maximum: 20 IU/kg)

20 IU/kg (maximum: 30 IU/kg)

20 IU/kg (maximum: 30 IU/kg)

30 Units/kg (maximum: 50 Units/kg)

45 mcg/kg

Repeat dosing

Should not repeat in <24 hours

Should not repeat in <24 hours

Should not repeat in <5-7 days

Should not repeat in <24 hours

Should not repeat in <2 hours

Special Populations

Hepatic Impairment

Avoid use in patients with hepatic impairment (Child-Pugh Class A, B, and C).1

Renal Impairment

The manufacturer makes no specific dosage recommendations for patients with renal impairment.1

Geriatric Patients

The manufacturer makes no specific dosage recommendations for geriatric patients.1

Cautions

Contraindications

Warnings/Precautions

Warnings

Thrombotic events

Serious thrombotic events have occurred with fitusiran and a boxed warning about this risk has been included in the prescribing information for the drug.1 In clinical trials, thrombosis was reported in 2.6% of patients receiving the unapproved 80 mg once monthly dose of fitusiran (2.3 events per 100 personyears), including one fatal cerebral venous sinus thrombosis.1 Thrombosis occurred in 1.4% of patients receiving the antithrombinbased regimen targeting 15-35% antithrombin (AT) activity (0.8 events per 100 personyears).1 These studies generally excluded patients with thrombophilia or a history of thrombosis.1

Risk factors for an increased risk of thrombosis include persistent AT activity <15%, prothrombotic comorbidities or indwelling venous catheters, not following perioperative bleed management protocols, or use of the unapproved 80 mg monthly dosage.1 Excessive use of clotting factor concentrates or bypassing agents for breakthrough bleeds also increases the risk of thrombosis.1 The benefits versus risks of using higher dosing regimens of these agents in patients with inadequate hemostasis should be considered prior to use.1

Clinicians should monitor antithrombin activity with an FDAapproved assay and maintain levels at 15-35% to reduce thrombotic risk.1 Monitor patients for signs and symptoms of thrombosis; if thrombosis occurs, interrupt fitusiran therapy and manage the patient appropriately.1 Reassess the risks and benefits before resuming fitusiran therapy.1

Acute and Recurrent Gallbladder Disease

Treatment with fitusiran increases the risk of acute and recurrent gallbladder disease, including cholelithiasis and cholecystitis; a boxed warning about this risk has been included in the prescribing information for the drug.1 The fixed-dose regimen, including 80 mg once monthly, is not approved or recommended.1 In clinical studies, 17% of 270 patients who received the fixed-dose regimen experienced gallbladder events, and 4% underwent cholecystectomy.1

Among 286 patients who received the AT-based regimen targeting 15-35% antithrombin activity, 3.8% of patients experienced gallbladder events, and 0.3% (1 patient) required cholecystectomy.1 All but one patient resumed fitusiran after cholecystectomy; one patient who switched from fixed dosing to the AT-based regimen developed cholangitis and pancreatitis due to gallstone disease more than a year after surgery.1

Patients with gallbladder disease typically present with epigastric pain, generalized abdominal pain, indigestion, nausea, and/or vomiting.1 Monitor patients for signs and symptoms; obtain appropriate imaging and follow-up if gallbladder disease is suspected.1 Interrupt or discontinue fitusiran if gallbladder disease develops.1

Consider alternative therapy in patients with a history of symptomatic gallbladder disease.1

Other Warnings and Precautions

Hepatotoxicity

In two randomized studies of fitusiran 80 mg once monthly, elevations of ALT or AST >3 times the upper limit of normal (ULN) occurred in 32% of patients with hemophilia A or B with inhibitors and 18% of patients without inhibitors, compared with no such elevations in control groups.1 One patient developed moderate hepatic injury (ALT >300 units/liter and total bilirubin >3 mg/dL) attributed to fitusiran; liver tests continued to rise with repeated monthly dosing and normalized after discontinuation.1 The 80 mg monthly regimen is not approved or recommended.1

Among patients receiving the ATbased fitusiran regimen, 3.4% of patients experienced ALT elevations >3 times the ULN, with a median onset of 89 days (range, 15-768 days).1

Avoid fitusiran in patients with hepatic impairment (ChildPugh class A, B, or C).1

Obtain baseline AST, ALT, and total bilirubin prior to therapy; monitor monthly for at least 6 months after initiation and for 6 months following any dosage increase, then periodically as clinically indicated.1

If new or worsening liver test abnormalities occur, evaluate, manage appropriately, and continue monitoring until tests normalize.1 Interrupt fitusiran for ALT or AST >5 times the ULN, and weigh benefits and risks before resuming therapy after normalization.1 If elevations recur after reinitiation or if the patient develops jaundice with bilirubin 2.5 mg/dL due to hepatotoxicity, permanently discontinue fitusiran.1

Immunogenicity

In 4 studies (up to 250 weeks' duration), 3.4% (10/290) of adults treated with fitusiran for hemophilia developed lowtiter, mostly transient antibodies.1 These antibodies did not produce clinically significant effects on pharmacokinetics, pharmacodynamics, safety, or effectiveness.1

Specific Populations

Pregnancy

There are no data in pregnant women to assess the risk of birth defects, miscarriage, or other adverse maternal or fetal outcomes with fitusiran.1 Animal reproduction studies have not been conducted.1 It is unknown whether fitusiran causes fetal harm or affects reproductive capacity.1 Use fitusiran during pregnancy only when the potential benefits outweigh the risks to the fetus.1

Lactation

It is not known whether fitusiran or its metabolites are distributed into human milk or if the drug has any effects on the breastfed infant or on milk production.1 The safety of fitusiran during breastfeeding is unknown.1 The benefits of breastfeeding should be weighed against the clinical need for fitusiran and the potential adverse effects on the breastfed infant from the drug or from the underlying maternal condition.1

Females and Males of Reproductive Potential

Use of fitusiran in females using hormonal contraceptives may increase the risk of thrombotic events.1 Alternative nonhormonal contraception is recommended before and during fitusiran therapy.1

Pediatric Use

Safety and effectiveness of fitusiran for the treatment of hemophilia A or B, with or without factor VIII or IX inhibitors, in pediatric patients 12 years of age have been established.1 Use in this pediatric population is supported by evidence from adequate and wellcontrolled studies in adult and pediatric patients.1 Clinical studies included 60 pediatric patients 12-17 years of age treated with fitusiran.1 Safety and effectiveness have not been established in pediatric patients <12 years of age.1

Geriatric Use

Clinical studies of fitusiran included 3 patients with hemophilia 65 years of age.1 The number of patients 65 years of age was insufficient to determine whether response to fitusiran differs from that of younger patients.1

Hepatic Impairment

In clinical studies, increased serum transaminase elevations were observed; avoid use of fitusiran in patients with hepatic impairment (ChildPugh Class A, B, or C).1

Renal Impairment

No clinical studies have been conducted to evaluate the effects of renal impairment on pharmacokinetics of fitusiran.1 In a population pharmacokinetic analysis, mild renal impairment had no effect on exposure of fitusiran.1

Common Adverse Effects

The most common adverse reactions, occurring in 10% of patients treated with fitusiran at the recommended ATbased dosage regimen, were viral infection, nasopharyngitis, and bacterial infection.1

Drug Interactions

No formal drug interaction studies have been conducted.1

In vitro studies show that fitusiran is unlikely to cause or be affected by cytochrome P-450 or transportermediated drug interactions at clinically relevant concentrations.1

Clotting Factor Concentrates or Bypassing Agents

Fitusiran prophylaxis increases thrombin generation and further increases peak thrombin when used with clotting factor concentrates or bypassing agents.1

Hormonal Contraceptives

Hormonal contraceptives may increase thrombotic risk in patients receiving fitusiran.1 Estrogenbased contraceptives increase thrombosis risk in women with inherited AT deficiency.1 Advise patients to use an alternative nonhormonal contraception before and during therapy with fitusiran.1

Other Information

Description

Fitusiran is an antithrombindirected, doublestranded, small interfering ribonucleic acid; the drug reduces antithrombin production and increases thrombin generation to enhance clotting ability.1 Lower antithrombin (AT) activity correlated with reduced bleeding rates, but persistent AT activity <15% increased thrombotic risk.1

In clinical trials, most patients achieved steadystate AT activity within 23 weeks of starting or adjusting dosing.1 After discontinuation, AT activity remained <60% for about 6 months, after which standard doses of clotting factor concentrates or bypassing agents may be used.1 Recovery to 15-35% AT activity after levels dropped to <15% required about 12 weeks before initiating a lower dose.1 Antithrombin reduction was similar in patients with hemophilia A and B, with or without inhibitors.1

The pharmacokinetics of fitusiran were evaluated in patients with hemophilia A or B, with or without inhibitors.1 Fitusiran demonstrates liverdriven pharmacodynamics rather than plasmadriven effects.1 Dosing aims to maintain plasma antithrombin activity between 15-35% using 10, 20, or 50 mg regimens administered monthly or every 2 months.1 Fitusiran shows doseproportional plasma exposure after subcutaneous administration with no accumulation after repeated monthly dosing.1 Peak plasma concentration is reached in approximately 2.8-3.8 hours.1 The drug distributes primarily to the liver, with about 96.6% protein binding at clinically relevant concentrations.1 The mean terminal elimination halflife ranges from 5.57-7.98 hours, and metabolism occurs via endo and exonucleases to progressively shorter oligonucleotides.1 Fitusiran is not metabolized by cytochrome P450 enzymes and is not a substrate of transporters.1 Following administration of a 50-mg dose, approximately 14.6% of the drug is excreted unchanged in urine within 24 hours.1 Fitusiran has only been studied in male patients.1 Race does not appear to affect the pharmacokinetics of fitusiran.1

Advice to Patients

Additional Information

The American Society of Health-System Pharmacists, Inc. represents that the information provided in the accompanying monograph was formulated with a reasonable standard of care, and in conformity with professional standards in the field. Readers are advised that decisions regarding use of drugs are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and that the information contained in the monograph is provided for informational purposes only. The manufacturer's labeling should be consulted for more detailed information. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information contained in the monograph is not a substitute for medical care.

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

Fitusiran is available through designated specialty pharmacies. Contact the manufacturer or consult the QfitliaTM website ([Web]) for specific information.

Fitusiran

Routes

Dosage Forms

Strengths

Brand Names

Manufacturer

Parenteral

Injection, for subcutaneous use

50 mg/0.5 mL

Qfitlia® (available in a single-patient-use prefilled pen)

Genzyme Corporation

20 mg/0.2 mL

Qfitlia® (available in a single-dose vial)

Genzyme Corporation

Copyright

AHFS® Drug Information. © Copyright, 1959-2025, Selected Revisions September 10, 2025. American Society of Health-System Pharmacists, Inc., 4500 East-West Highway, Suite 900, Bethesda, MD 20814.

References

Only references cited for selected revisions after 1984 are available electronically.

1. Genzyme Corporation. Qfitlia® (fitusiran) SUBCUTANEOUS prescribing information. 2025 Mar. [Web]

2. Food and Drug Administration. Search Orphan Drug Designations and Approvals. Silver Spring, MD. From FDA website. Accessed 2025 July 23.[Web] [Web]

3. Food and Drug Administration. Center for Drug Evaluation and Research. Application number 219019Orig1s000: Integrated review. [Web]

4. Young G, Srivastava A, Kavakli K, et al. 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. 2023;401(10386):1427-1437.

5. Srivastava A, Rangarajan S, Kavakli K, et al. Fitusiran prophylaxis in people with severe haemophilia A or haemophilia B without inhibitors (ATLAS-A/B): a multicentre, open-label, randomised, phase 3 trial. Lancet Haematol. 2023;10(5):e322-e332.

6. Young G, Kavakli K, Klamroth R, et al. Safety and efficacy of a fitusiran antithrombin-based dose regimen in people with hemophilia A or B: the ATLAS-OLE study. Blood. 2025;145(25):2966-2977.

7. Kenet G, Nolan B, Zulfikar B, et al. Fitusiran prophylaxis in people with hemophilia A or B who switched from prior BPA/CFC prophylaxis: the ATLAS-PPX trial. Blood. 2024;143(22):2256-2269. doi:10.1182/blood.2023021864

8. World Federation of Hemophilia. Guidelines for the Management of Hemophilia. 3rd ed. World Federation of Hemophilia; 2020. Accessed 2025 Jul 30. [Web]

9. National Hemophilia Foundation. MASAC Document 290 - MASAC Recommendations Concerning Products Licensed for the Treatment of Hemophilia and Selected Disorders of the Coagulation System. National Hemophilia Foundation website. Published 2024 October 2. Accessed 2025 Juln 30. [Web]