HepaGam B®

Product Overview:

• Brand Name: HepaGam B®
• Type: Hepatitis B Immune Globulin (Human) Injection
• Form: Liquid, >312 IU/mL
• Standard: WHO International Reference Preparation
• Distributor (in Canada): Emergent BioSolutions Canada Inc.

Indications and Clinical Use:

• Post-exposure Prophylaxis: Indicated for the treatment of acute exposure to hepatitis B virus (HBV) through blood, perinatal exposure, sexual exposure, and household exposure.
• Acute Exposure: For needlestick, bite, sharps, mucous membrane contact, or oral ingestion involving HBsAg-positive materials.
• Perinatal Exposure: For infants born to HBsAg-positive mothers.
• Sexual Exposure: For sexual partners of HBsAg-positive individuals.
• Household Exposure: For infants under 12 months old with an HBsAg-positive primary caregiver.
• Prevention of Hepatitis B Recurrence Following Liver Transplantation: Authorized with conditions pending further studies to verify clinical benefits.

Dosage and Administration:

• Post-exposure Prophylaxis: Administer intramuscularly.
• Acute Exposure: 0.06 mL/kg as soon as possible after exposure, ideally within 24 hours.
• Perinatal Exposure: 0.5 mL within 12 hours of birth.
• Sexual Exposure: 0.06 mL/kg within 14 days of last contact.
• Household Exposure: 0.5 mL for infants.
• Liver Transplantation: Administer intravenously to maintain serum anti-HBs levels above 500 mIU/mL.
• Dosing Regimen: First dose during the anhepatic phase, followed by daily doses for one week, biweekly for three months, and monthly thereafter.

Contraindications:

• Severe thrombocytopenia or coagulation disorders if intramuscular administration is contraindicated.
• Patients with a history of severe allergic reactions to any component of the product.
• Patients with IgA deficiency who may have antibodies against IgA.

Warnings and Precautions:

• Viral Transmission: Although measures are taken to reduce risk, products made from human plasma may still transmit infectious agents.
• Hypersensitivity: True hypersensitivity reactions are rare but possible, particularly in patients with IgA deficiency.
• Thrombosis: Rare thrombotic events have been reported; administer at the minimum practical concentration and infusion rate in patients at risk.
• Renal Dysfunction: Intravenous immune globulin products have been associated with renal dysfunction; monitor renal function in at-risk patients.
• Special Populations:
• Pregnant Women: Immune globulins have been used widely without apparent negative effects.
• Nursing Women: Caution is advised as it is unknown whether the product is excreted in human milk.
• Pediatrics: Safe and effective in infants for preventing vertical transmission of hepatitis B.
• Geriatrics: Safety and effectiveness not established.

Adverse Reactions:

• Common Reactions: Include headache, nausea, pyrexia, arthralgia, myalgia, and injection site reactions.
• Severe Reactions: Include hypersensitivity, anaphylactic reactions, and thrombotic events.
• Clinical Trials: Most adverse events in clinical trials were mild, with no serious events reported in healthy volunteers.

Storage and Stability:

• Store under refrigeration (2°C to 8°C). Do not freeze. Use before the expiration date on the label.

Mechanism of Action:

• Provides passive immunity by supplying antibodies against hepatitis B surface antigen (anti-HBs), preventing HBV recurrence post-liver transplantation, and reducing the risk of HBV infection after exposure.

Clinical Trials:

• Post-exposure Prophylaxis: Demonstrated high efficacy in preventing hepatitis B infection in infants and adults.
• Liver Transplantation: Ongoing trials with preliminary data showing significant prevention of HBV recurrence.

Pharmacokinetics:

• Half-life: Approximately 24.5 days following intramuscular administration.
• Distribution: IgG is quickly distributed between plasma and extravascular fluid.