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Qfitlia® (fitusiran) has a well-established safety profile1

Most Common Adverse Reactions

Thrombotic Events

Gallbladder Events

Hepatotoxicity

Adverse Reactions

The safety of Qfitlia has been extensively studied for over 10 years in the largest hemophilia preapproval clinical program2-4

Adverse reactions reported in ≥5% of patients treated with the AT-DR of Qfitlia (N=286)1
Adverse reaction% of patients
Viral infection*29
Nasopharyngitis*26
Bacterial infection*11
Hepatic injury†8
Arthralgia*8
Prothrombin fragment 1.2 increased7
Injection site reaction‡6
Headache5
Cough*5



Thrombotic events (TEs)

Serious TEs have occurred in patients treated with Qfitlia with risk factors for TEs1

1.4% of patients (4 out of 286) receiving Qfitlia prophylaxis under the antithrombin-based dosing regimen (AT-DR) experienced TEs.1,5

The risk of thrombosis is greater in patients when1: 

  •  Antithrombin levels are consistently <15% 
  •  There are comorbidities that predispose to thrombosis 
  •  The BMG=Bleed Management Guide; is not followed in postoperative settings 
  •  Presence of indwelling venous catheters 
  •  Qfitlia is used at a fixed dose of 80 mg monthly

Gallbladder events1

Treatment with Qfitlia is associated with an increased occurrence of acute and recurrent gallbladder disease, including cholelithiasis and cholecystitis. Monitor patients for signs and symptoms of acute and recurrent gallbladder disease

  • In 286 patients who received the AT-DR, 3.8% (11 out of 286) experienced gallbladder events and 0.3% (1 patient) underwent cholecystectomy§
  • Patients diagnosed with acute or recurrent gallbladder disease in the clinical program most commonly presented with epigastric pain, generalized abdominal pain, indigestion, nausea, and/or vomiting
  • Interrupt or discontinue Qfitlia if acute or recurrent gallbladder disease occurs
  • Consider alternative treatment for patients with a history of symptomatic gallbladder disease 




     

Hepatotoxicity1

On the AT-DR, 3.4% (10 out of 286) of patients treated with Qfitlia had at least one ALT value greater than 3x ULN, with a median onset of 89 days after initial dosing (range 15 to 768 days)

  • Avoid use of Qfitlia in patients with established hepatic impairment (Child-Pugh Class A, B, and C)
  • Dosage interruptions due to increased transaminases occurred in 2/286 (0.7%) patients
  • Obtain baseline LFTs, including AST, ALT, and total bilirubin, prior to initiating Qfitlia; monthly for at least the first 6 months of Qfitlia use; monthly for at least 6 months after a dose increase; and periodically thereafter as clinically indicated

Adverse reactions1

The most common adverse reactions reported in ≥10% of patients treated with the AT-DR of Qfitlia were:  

  • Viral infection: 29% of patients (83 out of 286)
  • Nasopharyngitis: 26% of patients (74 out of 286)
  • Bacterial infection: 11% of patients (31 out of 286) 

Low discontinuation rates due to adverse events were observed in 1.4% (4 out of 286) of patients.

  • Adverse reactions that resulted in permanent discontinuation of Qfitlia included liver injury, postoperative deep vein thrombosis, cerebral infarction, and pruritus   
     

* Includes similar terms.1   
† Hepatic injury includes increased ALT, increased AST, and liver injury.1   
‡ Includes injection site bruising, injection site erythema, injection site pain, injection site hematoma, injection site atrophy, injection site hemorrhage, injection site discomfort, injection site swelling, injection site discoloration, injection site pruritus, injection site induration, injection site nodule, injection site mass, injection site vesicles, injection site deformation, injection site rash, injection site joint pain, and application site erythema.1   
§ One patient who was previously treated with a fixed monthly dose of 80 mg had a cholecystectomy.1

ALT=alanine aminotransferase; AST=aspartate aminotransferase; BMG=Bleed Management Guidelines; LFT=liver function test; ULN=upper limit of normal.

Explore antithrombin-based dosing

While starting patients on Qfitlia, measuring antithrombin levels will help inform dosing decisions.1,6
 

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Discover Qfitlia-specific bleed management guidelines

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INDICATION

Qfitlia® (fitusiran) is an antithrombin (AT)-directed small interfering ribonucleic acid (siRNA) indicated for routine prophylaxis to prevent or reduce the frequency of bleeding episodes in adult and pediatric patients aged 12 years and older with hemophilia A or B with or without Factor VIII or IX inhibitors.

IMPORTANT SAFETY INFORMATION

WARNING: THROMBOTIC EVENTS AND ACUTE AND RECURRENT GALLBLADDER DISEASE

THROMBOTIC EVENTS
Serious thrombotic events have occurred in Qfitlia-treated patients with risk factors for thromboembolism including persistent antithrombin (AT) activity less than 15%, use of Qfitlia 80 mg once monthly, presence of indwelling venous catheters, and in the post-operative setting when Bleed Management Guidelines were not followed. 

Monitor AT activity using an FDA-cleared test and target AT activity 15-35% to reduce the risk of thrombosis. Monitor patients for signs and symptoms of thrombotic events. Interrupt Qfitlia in patients with a thrombotic event and manage as clinically indicated.

ACUTE AND RECURRENT GALLBLADDER DISEASE
Acute and recurrent gallbladder disease, including cholelithiasis and cholecystitis have occurred in Qfitlia-treated patients, some of whom required cholecystectomy or had complications (e.g., pancreatitis) related to gallbladder disease. Monitor patients for signs and symptoms of acute and recurrent gallbladder disease. 

Consider interruption or discontinuation of Qfitlia if gallbladder disease occurs. Consider alternative treatment for hemophilia in patients with a history of symptomatic gallbladder disease.

WARNINGS AND PRECAUTIONS
Thrombotic Events:  

  • Serious thrombotic events have been reported in Qfitlia-treated patients. Thrombotic events were reported in 2.6% of patients receiving the 80 mg once monthly dose, including a fatal event of cerebral venous sinus thrombosis. The 80 mg once monthly dose is not approved or recommended for use. Thrombotic events were reported in 1.4% of patients receiving Qfitlia prophylaxis using the AT-based dose regimen (AT-DR) that targeted AT activity 15-35%
  • The risk of thrombosis is greater in patients with certain risk factors (see Boxed WARNING). Treatment of breakthrough bleeding episodes with clotting factor concentrate (CFC) or bypassing agent (BPA) at a dose greater or more frequent than recommended may also increase thrombotic risk

Acute and Recurrent Gallbladder Disease: 

  • Treatment with Qfitlia is associated with an increased occurrence of acute and recurrent gallbladder disease, including cholelithiasis and cholecystitis (see Boxed WARNING). In the 270 patients in the clinical studies who received Qfitlia at a fixed dose of 80 mg once monthly, 17% experienced gallbladder events and 4% underwent cholecystectomy. In 286 patients who received the AT-DR, 3.8% experienced gallbladder events and 0.3% underwent cholecystectomy

Hepatotoxicity: 

  • In the two randomized studies testing Qfitlia 80 mg once monthly, alanine transaminase (ALT) and aspartate transaminase (AST) elevations above 3 times the upper limit of normal (ULN) occurred in 32% of patients with hemophilia with inhibitors and 18% of patients with hemophilia without inhibitors. There was one case of moderate hepatic injury attributable to Qfitlia use. On the AT-DR, 3.4% of patients treated with Qfitlia had at least one ALT value >3x ULN
  • Avoid use of Qfitlia in patients with hepatic impairment (Child-Pugh Class A, B, and C)
  • Obtain baseline liver tests, including AST, ALT, and total bilirubin, prior to initiating Qfitlia, monthly for at least the first 6 months of Qfitlia use, monthly for at least 6 months after a dose increase, and periodically thereafter as clinically indicated  
  • If new or worsening liver test abnormalities occur, initiate medical management as appropriate and monitor until they return to baseline. If ALT or AST elevations >5x ULN occur, interrupt Qfitlia treatment. If Qfitlia is restarted and ALT or AST elevations >5x ULN reoccur or the patient experiences jaundice due to hepatotoxicity with other causes of liver test elevation ruled out, permanently discontinue Qfitlia

DRUG INTERACTIONS
Hypercoagulability with Concomitant Use of CFC or BPA: Qfitlia prophylaxis leads to increased thrombin generation with additive increase in peak thrombin when used concomitantly with CFC or BPA.

ADVERSE REACTIONS
Common adverse reactions (incidence ≥10%) are viral infection, nasopharyngitis, and bacterial infection.

Please see full Prescribing Information, including Boxed WARNING.

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INDICATION

IMPORTANT SAFETY INFORMATION

References: 1. Qfitlia Prescribing Information. Genzyme Corporation. Cambridge, MA. 2. Pasi KJ, et al. N Engl J Med. 2017;377(9):819-828. 3. Data on file CSR. SAR439774-LTE15174 - fitusiran. November 2023. 4. Young G, et al. Res Pract Thromb Haemost. 2023;7(4):e100179. 5. Shapiro AD, et al. Res Pract Thromb Haemost. 2022;7(1):100007. 6. Data on file.

©2026 Sanofi. All rights reserved. All trademarks mentioned are the property of the Sanofi group except where trademarks are owned by third parties. MAT-US-2413068-v2.0-07/2026 Last Updated: July 2026

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