Fidanacogene Elaparvovec Dosage

Medically reviewed by Drugs.com. Last updated on Aug 20, 2024.

Usual Adult Dose for Hemophilia B

5 x 10(11) vector genomes per kg (vg/kg) of body weight IV once as a single dose

Calculation of patient's dose weight:

• BMI 30 kg/m2 or less: Dose Weight = Actual body weight
• BMI greater than 30 kg/m2: Dose Weight (kg) = 30 kg/m2 x [Height(m)]2

Calculation of patient's dose volume in mL: Dose weight in kg divided by 20 = dose in mL

• The division factor 20 represents the amount of vector genomes per mL of the suspension (1 x 10[13] vg/mL) divided by the per kg dose (5 x 10[11] vg/kg).

Comments:

• For one-time single dose IV infusion only
• Dosing is based on BMI in kg/m2.
• Diluted suspension should be administered as a peripheral IV infusion over approximately 60 minutes (3 mL/min).
• Safety and efficacy have not been established in patients 65 years or older.
• For examples of dose calculation, refer to the manufacturer product information.

Use: For the treatment of adults with moderate to severe hemophilia B (congenital factor IX deficiency) who use factor IX prophylaxis therapy, OR have current or historical life-threatening hemorrhage, OR have repeated serious bleeding episodes, AND do not have neutralizing antibodies to adeno-associated virus serotype Rh74var (AAVRh74var) capsid as detected by a US FDA-approved test

Renal Dose Adjustments

Data not available

Liver Dose Adjustments

Data not available

Precautions

CONTRAINDICATIONS: None

Safety and efficacy have not been established in patients younger than 18 years.

Consult WARNINGS section for additional precautions.

Dialysis

Data not available

Other Comments

Administration advice:

• Select patients for therapy based on a US FDA-approved companion diagnostic for this product.
• This product should be administered in a hospital or clinic under the supervision of a health care provider experienced in the treatment of hemophilia.
• This product should be administered where personnel and equipment are immediately available to treat an infusion-related reaction.
• This product contains genetically modified vectors and personal protective equipment (gloves, safety goggles, laboratory coat and sleeves) should be worn while preparing and administering.
• An in-line 0.2 micron IV filter may be used for administration.
• Do not administer as an IV push or bolus.
• Do not infuse in the same IV line with any other products. Do not use a central line or port.
• Confirm that the patient identity matches the patient-specific identifier number on the outer carton.
• Monitor patients during and for at least 3 hours after infusion.
• After infusion of the entire bag contents, flush the infusion line using local site procedures.

Patient selection:

• Test for preexisting neutralizing antibodies to AAVRh74var using the US FDA-approved companion diagnostic. DO NOT administer this product to patients with a positive test.
• Perform factor IX inhibitor testing prior to the infusion. DO NOT administer to patients with a positive test or a history for factor IX inhibitor.
• Perform HIV testing prior to infusion. DO NOT administer to patients with CD4+ cell count less than 200 mm3 or viral load of 20 copies/mL or greater in case of evidence of HIV-1 or HIV-2 infection.
• DO NOT administer to patients with hypersensitivity to factor IX replacement product.
• Perform liver health assessment which includes liver function tests (ALT, AST, alkaline phosphatase [ALP] , bilirubin, albumin), laboratory tests for active hepatitis B or C, liver elastography and/or ultrasound and other laboratory assessments for liver fibrosis .
• DO NOT administer this product to patients with liver-related coagulopathy, hypoalbuminemia, persistent jaundice, cirrhosis, portal hypertension, splenomegaly, hepatic encephalopathy, hepatic fibrosis, or active viral hepatitis.
• In case of radiologic liver abnormalities or sustained liver enzyme elevations, consider consulting with a hepatologist to assess eligibility for this product.

Use of corticosteroids:

• Consider administering a course of corticosteroids if:
• There is a single increase in either AST or ALT equal to or greater than 1.5-fold from baseline after screening and prior to infusion (even if within normal range).
• Consecutive increases in AST or ALT or both on 2 subsequent blood tests (even if within normal range).
• A decrease of factor IX activity that could trigger the risk of bleeding in the absence of alternative etiology or decrease in factor IX activity on 2 consecutive blood tests especially during the first 4 months post-infusion.
• Consult the manufacturer product information for additional information on oral corticosteroid schedule and dosing.

Storage requirements:

• This product is shipped and delivered frozen between -100C to -60C (-148F to -76F). Upon receipt, immediately place in the freezer between -90C to -60C (-130F to -76F).
• Store in the original package to avoid direct sunlight and ultraviolet light exposure.
• Store upright in the original package. If cartons or individual vials are tipped over or inverted during storage and handling, place back upright immediately. Do not shake this product.
• Frozen vials will take up to 1 hour to thaw at room temperature (up to 30C [86F]). The total time at room temperature between removing vials from frozen storage until the beginning of dose preparation should be no more than 3 hours.
• Once thawed, this product should not be refrozen and may be stored refrigerated at 2C to 8C (36F to 46F) in the inner carton up to 24 hours.
• Following dilution, stability has been demonstrated for 24 hours at 2C to 30C (36F to 86F). Use within 24 hours of dilution and dose preparation.

Reconstitution/preparation techniques:

• Consult the manufacturer product information for further preparation of diluent solution, preparation of suspension for infusion, and administration instructions.

IV compatibility:

• Compatible diluent: 0.9% Sodium Chloride with 0.25% human serum albumin
• Compatible materials:
• IV infusion container: Polyvinyl chloride (PVC), ethylene vinyl acetate (EVA), polyolefin (polyethylene and/or polypropylene)
• Infusion set (line material): PVC, polybutadiene, polyurethane, polyethylene

General:

• This product may be transmitted to persons around the patient receiving the treatment primarily through the urine and feces, and to some extent saliva, mucus, and semen. To minimize the risk of transmission, instruct patients regarding proper hand hygiene when coming into direct contact with their secretions or excretions. Precautions should be followed for 6 months after the infusion, especially in the case of pregnancy or immunodeficiency of close contacts.
• To report suspected adverse reactions, contact Pfizer Incorporated at 1-800-438-1985 or US FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
• If malignancy occurs, contact Pfizer Incorporated at 1-800-438-1985 to obtain instructions on collecting patient samples for testing.

Monitoring (Post-Administration):

• Liver enzymes (ALT and AST) and factor IX activity testing:
• Weeks 1 to 16: Once or twice per week
• Weeks 17 to 18: Weekly
• Weeks 19 to 52 (end of Year 1): At weeks 24, 32, 42, and 52
• Year 2 to end of Year 3: Quarterly
• Year 4 to end of Year 6: Twice a year
• After Year 6: Annually
• It is recommended to use the same laboratory facility for monitoring over time to minimize interlaboratory variability.
• Monitor patients for factor IX inhibitors, especially if the bleeding is not controlled, or plasma factor IX activity levels decrease.
• Perform liver ultrasound (annually) and alpha-fetoprotein (AFP) testing in patients with risk factors for hepatocellular carcinoma.

Patient advice:

• Immediately inform medical staff if symptoms of infusion reaction develop.
• If necessary, complete the course of corticosteroids as prescribed.
• Do not donate blood, organs, tissues, or cells for transplantation after infusion.
• Male patients: Do not donate sperm; be abstinent or use a male condom for up to 6 months after therapy.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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