Antihemophilic Factor (recombinant), Fc Fusion Protein (Monograph)

Brand name: Eloctate
Drug class: Hemostatics

Medically reviewed by Drugs.com on Sep 17, 2023. Written by ASHP.

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Introduction

Biosynthetic (recombinant DNA origin) preparation of blood coagulation factor VIII covalently linked to the Fc domain of human IgG₁.

Uses for Antihemophilic Factor (recombinant), Fc Fusion Protein

Hemophilia A

On-demand treatment and control of bleeding episodes in patients with hemophilia A (congenital factor VIII deficiency; classic hemophilia).

Maintenance of hemostasis in patients with hemophilia A undergoing surgery (i.e., perioperative management of bleeding).

Routine prophylaxis (i.e., administration at regular intervals) to reduce frequency of bleeding events.

Designated an orphan drug by FDA for treatment of hemophilia A.

Not indicated for the treatment of von Willebrand disease.

The World Federation of Hemophilia and Medical and Scientific Advisory Council (MASAC) of the National Hemophilia Foundation publishe guidelines on the management of hemophilia. Guidelines generally support the use of factor VIII products for prophylaxis and treatment of bleeding in patients with hemophilia A.

Several antihemophilic factor concentrates are available in the US for treatment of hemophilia A; these include a variety of plasma-derived and recombinant preparations. When selecting an appropriate antihemophilic factor preparation, consider patient and drug-specific factors in addition to emerging data.

Antihemophilic Factor (recombinant), Fc Fusion Protein Dosage and Administration

General

Patient Monitoring

• Monitor factor VIII activity to individualize dosage and assess response to therapy. Adequate levels of factor VIII should be attained and maintained during therapy. Careful control of the dose is especially important in cases of life-threatening bleeding or major surgery.

• Monitor for the development of factor VIII inhibitors. Perform a Bethesda inhibitor assay if expected plasma factor VIII levels are not attained or bleeding is not controlled with recommended dosages.

• If central venous access device (CVAD) is required, monitor for CVAD-related complications including local infections, bacteremia, and catheter-site thrombosis.

Administration

IV Administration

Administer by IV bolus infusion over several minutes.

Reconstitute the commercially available lyophilized powder prior to IV administration.

Reconstitution

Reconstitute with sterile water for injection (supplied by manufacturer). Allow drug vial and prefilled diluent syringe to warm to room temperature prior to reconstitution. Gently swirl vial until powder is completely dissolved; do not shake. Resultant solution should be clear to slightly opalescent and colorless; do not use if cloudy, discolored, or particulate matter observed.

Administer immediately or within 3 hours after reconstitution; do not refrigerate reconstituted solution.

Do not administer reconstituted solution in the same tubing or container with other drugs.

Consult manufacturer's labeling for specific instructions on reconstitution and preparation of antihemophilic factor (recombinant), Fc fusion protein.

Rate of Administration

Administer IV over a period of several minutes; determine administration rate by patient's comfort level (not to exceed 10 mL/minute).

Dosage

Dosage and potency expressed in terms of international units (IU) of antihemophilic factor activity. Potency is determined by a chromogenic substrate assay; however, both chromogenic assays and one-stage clotting assays are routinely used in US clinical laboratories for measurement of plasma factor VIII activity. In general, administration of 1 unit/kg of antihemophilic factor (recombinant), Fc fusion protein increases circulating factor VIII levels by approximately 2 IU/dL.

Individualize dosage and duration of therapy based on severity of factor VIII deficiency, location and extent of bleeding, and patient's clinical and pharmacokinetic (e.g., in-vivo recovery, half-life) response. Estimate dose required to achieve a particular percentage increase in plasma factor VIII with the following formula:

Dose required (IU) = body weight (in kg) × desired factor VIII rise (IU/dL or % of normal) x 0.5 (IU/kg per IU/dL)

Determine desired factor VIII level by the clinical situation and severity of bleeding. For recommendations on target factor VIII levels for a given clinical situation, see the specific dosage sections for various types of uses below. These calculations and suggested dosage regimens are only approximations and should not preclude appropriate clinical monitoring and individualization of dosage based on the hemostatic requirements of patients. Measure patient's factor VIII activity after a dose is given to verify calculated dose.

If calculated dose is ineffective in achieving appropriate factor VIII levels, consider possibility of inhibitor development.

Pediatric Patients

Hemophilia A

Higher doses or more frequent dosing may be required in patients <6 years of age because of increased clearance per kg of body weight and shorter half-life. Dosage requirements in patients ≥6 years of age generally similar to those in adults.

On-Demand Treatment and Control of Bleeding

IV

Minor or moderate bleeding (e.g., joint, superficial muscle [except iliopsoas] without neurovascular compromise, deep laceration and renal, superficial soft tissue, mucous membranes): Initial dose of 20–30 IU/kg to achieve a factor VIII level of at least 40–60% of normal; repeat dose every 12–24 hours for patients <6 years of age or every 24–48 hours for patients ≥6 years of age until bleeding resolves.

Major bleeding (e.g., life- or limb-threatening, iliopsoas and deep muscle with neurovascular injury, GI, retroperitoneal, intracranial): Initial dose of 40–50 IU/kg to achieve a factor VIII level of at least 80–100% of normal; repeat dose every 8–24 hours for patients <6 years of age or every 12–24 hours for patients ≥6 years of age until bleeding resolves (approximately 7–10 days).

Perioperative Management of Bleeding

IV

Minorsurgery (e.g., uncomplicated dental extraction): Initial dose of 25–40 IU/kg to achieve a factor VIII level of 50–80% of normal. Repeat dose every 12–24 hours for patients <6 years of age or every 24 hours for patients ≥6 years of age for at least 1 day until healing is achieved.

Major surgery (e.g., intracranial, intra-abdominal, joint replacement): Initial preoperative dose of 40–60 IU/kg to achieve a factor VIII level of at least 80–120% of normal. Repeat with dose of 40–50 IU/kg after 6–24 hours for patients <6 years of age or every 8–24 hours for patients ≥6 years of age, then every 24 hours thereafter to maintain factor VIII levels within target range. Once adequate wound healing achieved, continue therapy for at least 7 days to maintain target factor VIII levels.

Routine Prophylaxis of Bleeding Episodes

IV

Children ≥6 years of age: Manufacturer recommends initial dosage of 50 IU/kg every 4 days. Adjust dosage to 25–65 IU/kg every 3–5 days based on response.

Children <6 years of age: Manufacturer recommends initial dosage of 50 IU/kg twice weekly. More frequent or higher doses up to 80 IU/kg may be required. Adjust dosage to 25–65 IU/kg every 3–5 days based on response.

MASAC states that prophylactic therapy should be instituted at an early age (e.g., 1–2 years) prior to the onset of frequent bleeding.

Individualize prophylactic dosage regimens; evaluate patients periodically to determine continued need for prophylaxis.

Adults

Hemophilia A

On-Demand Treatment and Control of Bleeding

IV

Minor or moderate bleeding (e.g., joint, superficial muscle [except iliopsoas] without neurovascular compromise, deep laceration and renal, superficial soft tissue, mucous membranes): Initial dose of 20–30 IU/kg to achieve a factor VIII level of at least 40–60% of normal; repeat dose every 24–48 hours until bleeding resolves.

Major bleeding (e.g., life- or limb-threatening, iliopsoas and deep muscle with neurovascular injury, GI, retroperitoneal, intracranial): Initial dose of 40–50 IU/kg to achieve a factor VIII level of at least 80–100% of normal; repeat dose every 12–24 hours until bleeding resolves (approximately 7–10 days).

Perioperative Management of Bleeding

IV

Minorsurgery (e.g., uncomplicated dental extraction): Initial dose of 25–40 IU/kg to achieve a factor VIII level of at least 50–80% of normal. Repeat dose every 24 hours for at least 1 day until healing is achieved.

Major surgery (e.g., intracranial, intra-abdominal, joint replacement): Initial preoperative dose of 40–60 IU/kg to achieve a factor VIII level of at least 80–120% of normal. Repeat with dose of 40–50 IU/kg after 8–24 hours, then every 24 hours thereafter to maintain factor VIII levels within target range. Once adequate wound healing achieved, continue therapy for at least 7 days to maintain target factor VIII levels.

Routine Prophylaxis of Bleeding Episodes

IV

Manufacturer recommends initial dosage of 50 IU/kg every 4 days. Adjust dosage within range of 25–65 IU/kg every 3–5 days based on patient response.

Individualize prophylactic dosage regimens; evaluate patients periodically to determine continued need for prophylaxis.

Special Populations

Hepatic Impairment

No specific dosage recommendations at this time.

Renal Impairment

No specific dosage recommendations at this time.

Geriatric Patients

No specific dosage recommendations at this time.

Cautions for Antihemophilic Factor (recombinant), Fc Fusion Protein

Contraindications

• Life-threatening hypersensitivity reactions (e.g., anaphylaxis) to antihemophilic factor (recombinant), Fc fusion protein or other components of the preparation including sucrose, sodium chloride, L-histidine, calcium chloride, and polysorbate 20.

Warnings/Precautions

Hypersensitivity Reactions

Potential risk of hypersensitivity reactions, including anaphylaxis. If a hypersensitivity reaction occurs, discontinue drug immediately and initiate appropriate therapy.

Neutralizing Antibodies to Factor VIII

Risk for development of neutralizing antibodies (inhibitors) to factor VIII following treatment with any antihemophilic factor preparation. Reported to occur in approximately 20–30% of patients with severe hemophilia A and 5–10% of those with mild to moderate disease.

Monitor patients for development of inhibitors using appropriate clinical observation and laboratory tests. Suspect presence of inhibitors if expected factor VIII levels not achieved or bleeding not controlled with recommended dose, particularly in those who previously achieved a response.

Cardiovascular Risk Factors

Risk of cardiovascular events in hemophilia patients who have cardiovascular risk factors or cardiovascular disease may be similar to the risk in patients without hemophilia when clotting has been normalized by treatment with factor VIII.

Catheter-related Complications

Consider risk of central venous access device (CVAD)-related complications including local infections, bacteremia, and catheter-site thrombosis if such a device is required.

Monitoring Laboratory Tests

Monitor factor VIII levels using a validated test (e.g., one-stage clotting assay) to guide dosing and assess therapeutic response. Important to achieve and maintain adequate levels of factor VIII for effective hemostatic control during an acute bleeding episode or during surgery.

Monitor for development of inhibitors. Perform appropriate laboratory test (i.e., Bethesda assay) to confirm presence of inhibitors.

Specific Populations

Pregnancy

Not known whether drug can cause fetal harm or affect reproductive capacity; use during pregnancy only when clearly needed.

Lactation

Not known whether distributed into human milk. Consider known benefits of breast-feeding; mother's clinical need for antihemophilic factor (recombinant), Fc fusion protein; and any potential adverse effects of the drug or disease on infant.

Pediatric Use

Safety and efficacy evaluated in previously treated adolescents 12–18 years of age in principal efficacy study.

In a separate pediatric study evaluating patients <12 years of age, antihemophilic factor (recombinant), Fc fusion protein half-life was shorter and body weight-adjusted clearance was substantially higher in children 1–5 years of age than in older pediatric patients.

Geriatric Use

Insufficient experience in patients ≥65 years of age to determine whether geriatric patients respond differently than younger patients.

Hepatic Impairment

No information on use in patients with hepatic impairment.

Renal Impairment

No information on use in patients with renal impairment.

Common Adverse Effects

Adverse effects (>0.5%) in previously treated patients: arthralgia, malaise, myalgia, headache, rash.

Adverse effects (≥1%) in previously untreated patients: factor VIII inhibition, device-related thrombosis, papular rash.

Antihemophilic Factor (recombinant), Fc Fusion Protein Pharmacokinetics

Absorption

Plasma Concentrations

In adults, mean recovery of factor VIII is approximately 2.26 IU/dL for each 1 unit/kg of antihemophilic factor (recombinant), Fc fusion protein administered. Mean incremental recoveries in pediatric patients 1–5, 6–11, and 12–17 years of age are 1.92, 2.44, and 1.85 IU/dL, respectively.

Duration

Compared with conventional preparations of recombinant antihemophilic factor, exhibits increased time after dosing to 1% factor VIII activity suggesting potentially longer therapeutic duration.

Distribution

Extent

Not known whether antihemophilic factor (recombinant), Fc fusion protein is distributed into milk.

Elimination

Half-life

Following administration of a single 50-unit/kg dose given as a 10-minute IV injection in adults, terminal half-life was approximately 19.7 hours and time to reach 1% factor VIII activity was 5.1 days.

Compared with adults, pediatric patients appear to have a shorter half-life; in one study, half-life was approximately 12.7, 14.9, or 16.4 hours in pediatric patients 1–5, 6–11, or 12–17 years of age, respectively.

In pediatric patients 1–5 years of age, clearance is substantially increased compared with older pediatric patients and adults.

Compared with conventional preparations of recombinant antihemophilic factor, half-life of antihemophilic factor (recombinant), Fc fusion protein is prolonged, clearance is reduced, and time to 1% factor VIII activity above baseline is longer; however, peak plasma concentrations and incremental recovery are similar. Less frequent dosing and improved patient compliance may be possible with these differences.

Stability

Storage

Parenteral

Powder for Injection

2–8°C in original package; do not freeze or expose to direct sunlight. Freezing may damage prefilled diluent syringe.

May store at room temperature (≤30°C) for a single period of up to 6 months or until expiration date on label. Do not place back into refrigerator after storage at room temperature.

Reconstituted Solution

May store at room temperature (≤30°C); protect from direct sunlight. Use solution within 3 hours of reconstitution.

Actions

• Biosynthetic (recombinant DNA origin) preparation of blood coagulation factor VIII covalently linked to the Fc domain of IgG₁. Fc portion prolongs half-life of factor VIII through interaction with the Fc neonatal receptor. Factor VIII portion is similar in structure and function to endogenous factor VIII.

• Patients with hemophilia A have decreased levels of endogenous factor VIII, resulting in a hemorrhagic tendency and clinical manifestations such as bleeding into soft tissues, muscles, joints, and internal organs. Clinical severity and frequency of bleeding generally correlate with degree of deficiency of factor VIII activity. Patients with mild hemophilia A generally have >5% of normal activity, those with moderate disease generally have 1–5% of normal activity, and those with severe disease have <1% of normal activity.

• Administration of antihemophilic factor (recombinant), Fc fusion protein increases plasma levels of factor VIII and temporarily corrects coagulation defect in patients with hemophilia A. Also may shorten aPTT, which is typically prolonged in such patients.

• Produced by recombinant DNA technology in a human embryonic kidney (HEK) cell line; undergoes several purification processes (e.g., filtration, chromatography, detergent treatment) and is manufactured without proteins from human or animal sources.

Advice to Patients

• Advise patients to read the manufacturer-provided patient information and instructions for use.

• Inform patients to report to their clinician any adverse reactions or other issues following administration of the drug.

• Advise patients to immediately contact a clinician or proceed to an emergency room if a hypersensitivity reaction occurs; early signs of such hypersensitivity include rash, urticaria, pruritus, chest tightness, wheezing, or swelling of the face.

• Advise patients to contact their clinician or treatment facility if they experience a lack of a clinical response to antihemophilic factor (recombinant), Fc fusion protein, since this may indicate the presence of an inhibitor.

• Advise patient to inform clinician of existing or contemplated concomitant therapy, including prescription and OTC drugs, as well as any concomitant illnesses.

• Advise women to inform their clinician if they are or plan to become pregnant or plan to breast-feed. Advise patients that the risks to the mother and fetus are unknown if the drug is used during pregnancy.

• Advise patients of other important precautionary information.

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.

Antihemophilic factor (recombinant), Fc fusion protein is available only through specialty pharmacies. Contact the manufacturer for specific availability.

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