2.1 Recommended Dosage

For subcutaneous use only.

Use of QFITLIA is recommended under the supervision of a healthcare professional experienced in the treatment of hemophilia or bleeding disorders.

Monitor AT activity using an FDA-cleared test. Information on FDA-cleared tests for AT activity is available at http://www.fda.gov/CompanionDiagnostics.

Measure AT activity prior to initiation of QFITLIA. Do not initiate QFITLIA dosing if AT activity is <60%.

After QFITLIA is initiated, patients may continue their prior clotting factor concentrates (CFC) or bypassing agent (BPA) prophylaxis for the first 7 days of treatment. Discontinue CFC or BPA prophylaxis no later than 7 days after the initial dose of QFITLIA.

The starting dose of QFITLIA is 50 mg once subcutaneously every two months. Adjust the dose and/or dosing interval, if needed, to maintain AT activity between 15–35% [see Boxed Warning, Dosage and Administration (2.2) and Warnings and Precautions (5.1)].

2.2 Dosage Modification

Measure AT activity using an FDA-cleared test at Weeks 4 (Month 1), 12 (Month 3), 20 (Month 5) and 24 (Month 6) following the starting dose and after any dose modification.

• If any AT activity is <15%, a dose reduction is required. The lower dose should be initiated 3 months after the prior dose. AT measurements should be restarted after a dose reduction.
• If AT activity is >35% after 6 months, or if the patient has not achieved satisfactory bleed control, dose escalation should be considered. AT measurements should be restarted after a dose escalation.

Refer to Table 1 below for modified dosage based on AT activity levels.

Once the patient's target dose is identified based on AT activity 15–35%, measure AT activity annually. Additional AT measurements can be considered if bleeding control is not adequate.

After cessation of QFITLIA dosing, routine AT monitoring is not needed unless the patient is bleeding and treatment with CFC/BPA is required. Based on data from the clinical studies, a majority of patients have AT activity >60% by 6 months after the last QFITLIA dose, after which standard doses of CFC/BPA may be used.

2.3 Bleed Management

2.4 Preparation and Administration Instructions

QFITLIA is intended for use under the guidance of a healthcare provider. Provide proper training to patients and/or caregivers on the preparation and administration of QFITLIA prior to use, according to the Instructions for Use (IFU). A patient may self-inject QFITLIA or the patient's caregiver may administer QFITLIA. In pediatric patients 12 to 17 years of age, it is recommended that QFITLIA be administered by or under the supervision of an adult.

QFITLIA for subcutaneous administration is a clear, colorless to pale yellow solution. Do not use if the solution is discolored or cloudy, or if it contains visible flakes or particles. Do not use QFITLIA if it has been dropped or damaged.

If QFITLIA is stored at room temperature, it is ready for use. If QFITLIA is stored in the refrigerator, remove from the refrigerator and allow QFITLIA to reach room temperature, for at least 30 minutes.

Administer QFITLIA by subcutaneous injection in the thigh or abdomen region, except for the 2 inches (5 cm) around the navel. A caregiver can also inject QFITLIA in the outer area of the patient's upper arm. QFITLIA should not be injected into skin that is tender, damaged, bruised, or scarred. Do not inject into a vein.

To inject 10 mg or 20 mg of QFITLIA from the single-dose vial, it is recommended to use a sterile 1 mL Luer Lock syringe (polypropylene or polycarbonate), and a sterile 27 gauge ½ inch (13 mm) Luer Lock needle to withdraw and inject QFITLIA solution subcutaneously (see the Instructions for Use).

Discard unused product remaining in the prefilled pen or vial.

5.1 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 (2.3 events per 100 person-years), 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 antithrombin-based dose regimen (AT-DR) that targeted AT activity 15-35% (0.8 events per 100 person-years). Participants with established thrombophilia or a history of thrombosis were generally excluded from studies with QFITLIA.

The risk of thrombosis is greater in patients with persistent AT activity <15%, with comorbidities that predispose to thrombosis, when bleed management guidelines are not followed in the post-operative setting, when there is an indwelling venous catheter, and with use of the 80 mg once monthly (non-AT-based) dose. Treatment of breakthrough bleeding episodes with CFC or BPA at a dose greater or more frequent than recommended may also increase thrombotic risk [see Dosage and Administration (2.3)]. The decision to utilize higher dosing regimens of CFC or BPA in the setting of inadequate hemostasis requires an assessment of the benefits and risks and close clinical monitoring.

Monitor AT activity using an FDA-cleared test and target AT activity 15–35% to reduce the risk of thrombosis [see Dosage and Administration (2.1, 2.2) and Warnings and Precautions (5.1)]. Monitor patients for signs and symptoms of thrombotic events. Interrupt QFITLIA prophylaxis in patients with a thrombotic event and manage as clinically indicated.

Inform patients treated with QFITLIA to monitor for and report signs and symptoms of thrombotic events. Consider the benefits and risks of resuming QFITLIA prophylaxis following resolution of the thrombotic event.

5.2 Acute and Recurrent Gallbladder Disease

Treatment with QFITLIA is associated with an increased occurrence of acute and recurrent gallbladder disease including cholelithiasis and cholecystitis. QFITLIA at a fixed dose (including 80 mg once monthly) is not approved or recommended for use. In the 270 patients in the QFITLIA clinical studies who received the fixed dose (non-AT-based dose) once monthly regimen, 17% experienced gallbladder events and 4% (11 patients) underwent cholecystectomy.

In 286 patients who received the AT-DR, 3.8% experienced gallbladder events and 0.3% (1 patient) underwent cholecystectomy.

All but one of the patients who underwent cholecystectomy resumed QFITLIA after surgery. One patient who started on fixed dosing experienced cholangitis and pancreatitis caused by gallstone disease more than a year after cholecystectomy while receiving AT-DR.

Patients diagnosed with acute or recurrent gallbladder disease most commonly presented with epigastric pain, generalized abdominal pain, indigestion, nausea and/or vomiting. If gallbladder disease is suspected, appropriate imaging and clinical follow-up are indicated.

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

5.3 Hepatotoxicity

In the two randomized studies testing QFITLIA 80 mg once monthly, serum 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 compared to no events of AST or ALT elevation greater than 3× ULN in the control groups. There was one case of moderate hepatic injury (ALT elevation >300 U/L and total serum bilirubin >3 mg/dL) attributable to QFITLIA use. This patient had elevation of liver tests after a single 80 mg dose that continued to rise with repeated dosing of QFITLIA 80 mg once monthly. This patient's liver tests recovered with drug discontinuation. QFITLIA 80 mg once monthly is not approved or recommended for use.

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

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, and monthly for at least 6 months after a dose increase, and periodically thereafter as clinically indicated.

If new or worsening liver test abnormalities occur, perform appropriate diagnostic evaluations, initiate medical management as appropriate and monitor laboratory parameters until they return to baseline. If ALT or AST elevations greater than 5× ULN occur, interrupt QFITLIA treatment. Consider the benefits and risks of resuming QFITLIA prophylaxis following resolution of transaminase elevations. If you decide to restart QFITLIA, wait until liver tests have returned to baseline. If QFITLIA is restarted and ALT or AST elevations greater than 5× ULN reoccur or the patient experiences jaundice (total bilirubin ≥2.5 mg/dL) thought to be from hepatotoxicity with other causes of liver test elevation ruled out, permanently discontinue QFITLIA.

6.1 Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The pooled safety population described in the WARNINGS AND PRECAUTIONS reflect exposure to QFITLIA as fixed doses and AT-DR (N=335).

The safety of the QFITLIA AT-DR was assessed in 286 adult and pediatric male patients with hemophilia A or B with or without inhibitors [see Clinical Studies (14)].

Among patients who received the AT-DR, 93% were exposed for 6 months or longer and 83% were exposed for 12 months or longer. The median duration of exposure across the studies was 674 days (with a maximum of 896 days).

Serious adverse reactions occurred in 4/286 (1.4%) patients who received the AT-DR, two of whom had serious adverse reactions of cholecystitis.

Permanent discontinuation of QFITLIA due to an adverse reaction occurred in 4/286 (1.4%) patients receiving the AT-DR and included liver injury, post-operative deep vein thrombosis, cerebral infarction and pruritus.

Dosage interruptions of QFITLIA due to an adverse reaction occurred in 2/286 (0.7%) patients receiving the AT-DR and included increased serum transaminases.

The most common adverse reactions (≥10%) reported in patients treated with the AT-DR were viral infection, nasopharyngitis, and bacterial infection.

7.1 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 [see Boxed Warning, Dosage and Administration (2.3) and Warnings and Precautions (5.1)].

8.1 Pregnancy

8.2 Lactation

8.3 Females and Males of Reproductive Potential

8.4 Pediatric Use

The safety and effectiveness of QFITLIA for the treatment of hemophilia A or B with or without factor VIII or IX inhibitors have been established in pediatric patients aged 12 years and older. Use of QFITLIA in pediatric patients with hemophilia A and B is supported by evidence from adequate and well-controlled studies in adult and pediatric patients [see Adverse Reactions (6.1) and Clinical Studies (14)]. A total of 60 pediatric patients ages 12 to 17 were treated with QFITLIA in the clinical studies.

The safety and effectiveness of QFITLIA have not been established in pediatric patients below 12 years of age.

8.5 Geriatric Use

There were 3 patients with hemophilia 65 years of age and older in the clinical studies on QFITLIA. Clinical studies of QFITLIA did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects.

8.6 Hepatic Impairment

Serum transaminase elevations have been observed in the clinical studies [see Warnings and Precautions (5.3)]. Avoid use of QFITLIA in patients with established hepatic impairment (Child-Pugh Class A, B and C).

12.1 Mechanism of Action

QFITLIA is a double-stranded siRNA that causes degradation of AT messenger RNA (mRNA) through RNA interference, reducing plasma AT levels.

12.2 Pharmacodynamics

In clinical studies with QFITLIA in hemophilia patients, the primary pharmacodynamic (PD) measure was plasma AT activity. Lower AT activity levels were associated with lower annualized bleeding rates (ABR); however, persistent AT activity <15% is a risk factor for thrombotic events.

In Study LTE15174, the mean (SD) AT activity on the AT-DR was 24% (4.64).

Simulations to estimate time for AT activity to reach steady state found that regardless of the dose regimen, more than 99% of participants reached steady state AT levels (defined as <10% variability among consecutive measures) within 23 weeks following initiation of QFITLIA dosing or following dose escalation or de-escalation. The duration of persistent AT activity <60% (non-negligible impact of QFITLIA on coagulation) following QFITLIA treatment discontinuation was estimated to be approximately 6 months, after which standard doses of CFC/BPA may be administered. In patients with AT activity <15%, the time required prior to initiation of a lower dose was estimated to be 12 weeks to maximize the AT activity recovery to the target range of 15% to 35%. Extent of AT reduction with QFITLIA did not differ between patients with hemophilia A or B, with or without inhibitors.

12.3 Pharmacokinetics

The pharmacokinetic (PK) properties of fitusiran were evaluated following administration of QFITLIA in patients with hemophilia A or B, with or without inhibitors as summarized in Table 4. QFITLIA PD is driven by liver PK rather than plasma PK. The QFITLIA dosing strategy is based on maintaining plasma AT activity levels between 15–35% with 10, 20 or 50 mg dosing every month or every two months.

12.6 Immunogenicity

The observed incidence of anti-drug antibodies (ADA) is highly dependent on the sensitivity and specificity of the assay. Differences in assay methods preclude meaningful comparisons of the incidence of ADA in the studies described below with the incidence of ADA in other studies, including those of QFITLIA or of other fitusiran products.

During QFITLIA treatment (up to 250 weeks) in four studies, 10 out of 290 adults with hemophilia (3.4%) developed ADAs. All patients had low ADA titers, and the majority of patients had transient ADAs. There was no identified clinically significant effect of ADAs on PK, PD, safety, or effectiveness of QFITLIA.

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

In a 2-year carcinogenicity study in Sprague Dawley rats, fitusiran was not carcinogenic up to the highest dose tested following subcutaneous administration at doses of 0.03, 0.1 or 0.3 mg/kg/week in males and 0.1, 0.3, or 1 mg/kg/week in females. All doses in males and females were below the maximum recommended human dose (MRHD) of 50 mg per month based on body surface area (BSA) comparisons due to the sensitivity of wild type animals to the pharmacological effects of fitusiran. Fitusiran was not carcinogenic in Tg-rasH2 mice following subcutaneous administration at doses of 0.05, 0.15, or 0.5 mg/kg/week in males and 0.025, 0.08, or 0.25 mg/kg/week in females for 26 weeks.

Fitusiran was not mutagenic or clastogenic in a battery of genetic toxicity studies (i.e., in vitro bacterial reverse mutation assay, in vitro chromosomal aberration assay in human peripheral blood lymphocytes; in vivo bone marrow micronucleus test in rats).

In a chronic repeat dose toxicology study in Sprague Dawley rats, fitusiran-treated males received subcutaneous doses of 0.25, 0.5, or 1 mg/kg/week for 16 weeks then were cohabitated with fitusiran-naïve females. No adverse effects on male fertility endpoints were observed. All doses used in males were below the MRHD based on BSA comparisons due to the sensitivity of wild type animals to the pharmacological effects of fitusiran.

ATLAS-INH

ATLAS-INH was a randomized, multicenter, open-label clinical study in 57 adult and pediatric males (aged ≥12 years) with hemophilia A or B with inhibitory antibodies to factor VIII (FVIII) or factor IX (FIX), who previously received on-demand (episodic) treatment with BPAs for bleeding. Eligible patients were randomized in a 2:1 ratio to receive QFITLIA prophylaxis at a fixed dose 80 mg SC monthly (N=38) or BPA on-demand for treatment of breakthrough bleeding episodes (N=19) for 9 months. The 80 mg dose of QFITLIA is not approved because of an increased risk of serious thrombotic events, gallbladder events (including the need for cholecystectomy) and hepatotoxicity [see Boxed Warning and Warnings and Precautions (5.1, 5.2, 5.3)].

Of the 57 enrolled patients all had inhibitors; 45 patients had Hemophilia A and 12 had Hemophilia B. All patients in the study were male. The mean age of patients was 28.4 years, and 10 (17.5%) patients were 12–17 years of age. A total of 68.4% of patients were Asian, 28.1% were White, 1.8% were other, and 1.8% were multiple races; 5.3% patients identified as Hispanic or Latino and 94.7% identified as not Hispanic or Latino. Generally, the demographic and patient characteristics at baseline were comparable between the patients with hemophilia A and B.

ATLAS A/B

ATLAS A/B was a randomized, multicenter, open-label clinical study in 120 adult and pediatric males (aged ≥12 years) with hemophilia A or B without inhibitory antibodies to FVIII or FIX, who previously received on-demand (episodic) treatment with CFC for bleeding. Eligible patients were randomized in a 2:1 ratio to receive QFITLIA prophylaxis at a fixed dose of 80 mg SC monthly (N=80) or CFCs on-demand to treat breakthrough bleeding episodes (N=40) for 9 months. The 80 mg dose of QFITLIA is not approved because of an increased risk of serious thrombotic events, gallbladder events (including the need for cholecystectomy) and hepatotoxicity [see Boxed Warning and Warnings and Precautions (5.1, 5.2, 5.3)].

Of the 120 enrolled patients none had inhibitors; 93 patients had Hemophilia A and 27 had Hemophilia B. All patients in the study were male. The mean age of patients was 33.8 years, and 14 (11.7%) patients were 12–17 years of age. A total of 59.2% of patients were Asian, 37.5% were White, 1.7% were Black or African American, and 1.7% were multiple races; 3.3% of patients identified as Hispanic or Latino, 90.8% identified as not Hispanic or Latino, and 5.8% had ethnicity information unreported. Generally, the demographic and patient characteristics at baseline were comparable between the patients with hemophilia A and B.

ATLAS-OLE

A total of 227 patients rolled over from two clinical studies (ATLAS-INH and ATLAS-A/B) and ATLAS-PPX, a crossover study in patients previously on CFC or BPA prophylaxis, and were treated with QFITLIA in ATLAS-OLE. This multicenter open-label extension study evaluated the long-term safety and efficacy of QFITLIA in adult and pediatric males aged ≥12 years with hemophilia A or B, with or without inhibitory antibodies to FVIII or FIX. Eligible patients initially received QFITLIA 80 mg SC once monthly. The study was amended to evaluate the efficacy and safety of the AT-DR. A total of 213 patients were subsequently transitioned to AT-DR targeting AT activity of 15–35%.

In the AT-DR, the QFITLIA starting dose was 50 mg every two months, and dosing was individually adjusted based on AT activity level using the INNOVANCE Antithrombin assay. The dose could be increased to 50 mg every month or 80 mg every month or decreased to 20 mg every two months or 20 mg every month. QFITLIA was discontinued if AT activity was <15% at the lowest dose. No patients required escalation to 80 mg every month to achieve the target AT range. The dose required to maintain AT activity 15–35% in patients who initiated dosing on 50 mg every two months was: 50 mg every two months (35.8% of patients), 50 mg every month (15.7% of patients), 20 mg every two months (30.9% of patients), or 20 mg every month (2.9% of patients). A total of 14.7% of patients discontinued QFITLIA due to more than one AT activity <15%.

Patients with known co-existing coagulation disorders other than hemophilia A or B, increased risk of thrombosis as assessed by history of arterial or venous thromboembolism, significant valvular disease or atrial fibrillation, or co-existing thrombophilic disorder (e.g., Factor V Leiden mutation), AT activity <60% at screening, platelet count ≤100,000/μL, eGFR ≤45 mL/min (using the MDRD), or clinically significant liver disease were not eligible for enrollment.

The efficacy of QFITLIA AT-DR in ATLAS-OLE was evaluated for a duration of 7 months (primary efficacy period) following a 6-month dose adjustment period. The median observed annualized bleeding rate (IQR) for treated bleeds was 3.7 (0.0; 7.5) overall, 1.9 (0.0; 5.6) in inhibitor patients and 3.8 (0.0; 11.2) in non-inhibitor patients.

QFITLIA Prophylaxis Compared to On-Demand BPA or CFC

The efficacy results of QFITLIA prophylaxis using AT-DR in ATLAS-OLE compared to on-demand BPA or CFC control data from studies ATLAS-INH and ATLAS-A/B with respect to rate of treated bleeds, treated spontaneous bleeds, and treated joint bleeds are shown in Table 5 (patients with inhibitors) and Table 6 (patients without inhibitors) below.

16.1 How Supplied

QFITLIA (fitusiran) is a clear, colorless to pale yellow solution supplied in a single-dose prefilled pen or a single-dose vial. Each prefilled pen is designed to deliver 50 mg of QFITLIA in 0.5 mL (NDC 58468-0348-1). Each vial is designed to deliver 20 mg of QFITLIA in 0.2 mL (NDC 58468-0347-1).

QFITLIA is available in cartons containing 1 prefilled pen or 1 vial.

16.2 Storage and Handling

Use of BPAs or CFCs

Advise the patient and/or caregiver to discontinue prophylactic use of BPA or CFC no later than 7 days after starting QFITLIA to reduce the risk of thrombotic events. Discuss the appropriate dosing and frequency of BPA or CFC for breakthrough bleed management with the patient and/or caregiver prior to starting QFITLIA prophylaxis [see Dosage and Administration (2.3)].

Thrombotic Events

Advise the patient and/or caregiver of the risk of thrombotic events while receiving QFITLIA. Inform the patient and/or caregiver of the need for periodic measurements of AT activity that may result in changes to the QFITLIA dose and/or frequency of administration to reduce the risk for thrombosis. Educate patients on the signs and symptoms of thrombotic events and to seek immediate medical attention if new symptoms of thrombotic events occur [see Warnings and Precautions (5.1)].

Acute and Recurrent Gallbladder Disease

Inform the patient and/or caregiver of the risk of acute and recurrent gallbladder disease while receiving QFITLIA. Educate patients on the signs and symptoms of gallbladder disease and to seek medical attention if new symptoms of gallbladder disease occur [see Warnings and Precautions (5.2)].

Hepatotoxicity

Inform the patient and/or caregiver of the risk of hepatotoxicity and that blood tests to monitor for this risk will be obtained before starting QFITLIA and periodically during treatment. Inform patients to seek medical attention if symptoms of hepatotoxicity occur [see Warnings and Precautions (5.3)].

Administration Instructions

Provide training to the patient and/or caregiver on proper subcutaneous injection technique, including aseptic technique, and the preparation and administration of QFITLIA prior to use [see Dosage and Administration (2.4)].