Interferons bind to specific cell surface receptors and initiate a sequence of intracellular events that lead to the transcription of interferon-stimulated genes. The three major groups of interferons (alpha, beta, gamma) have partially overlapping biological activities that include immunoregulation such as increased resistance to microbial pathogens and inhibition of cell proliferation. Type 1 interferons (alpha and beta) bind to the alpha/ beta receptor. Interferon gamma binds to a different cell surface receptor and is classified as Type 2 interferon. Specific effects of interferon gamma include the enhancement of the oxidative metabolism of macrophages, antibody dependent cellular cytotoxicity (ADCC), activation of natural killer (NK) cells, and the expression of Fc receptors and major histocompatibility antigens.

ACTIMMUNE is an interferon gamma indicated for: Reducing the frequency and severity of serious infections associated with Chronic Granulomatous Disease (CGD); Delaying time to disease progression in patients with severe, malignant osteopetrosis (SMO)

The recommended dose is 50 mcg/m2 for patients whose body surface area is greater than 0.5 m2 and 1.5 mcg/kg/dose for patients whose body surface area is equal to or less than 0.5 m2 three times weekly. Monitor hematology, blood chemistries and urinalysis prior to the beginning of treatment and at 3-month intervals. If severe reactions occur, reduce dose by 50 percent or discontinue therapy until the adverse reaction abates.

Common adverse reactions (incidence rate 2% or greater) for ACTIMMUNE include fever, headache, rash, chills, injection site erythema or tenderness, fatigue, diarrhea.

Known hypersensitivity to interferon gamma, E. coli derived products, or any component of the product

Cardiovascular Disorders: Pre-existing cardiac conditions may be exacerbated. Neurologic Disorders: Reduce dose or discontinue if decreased mental status, gait disturbance, dizziness occur. Bone Marrow Toxicity: Monitor for neutropenia and thrombocytopenia particularly when administering ACTIMMUNE in combination with other potentially myelosuppressive agents. Hepatic Toxicity: Reduce dose or discontinue to reverse severe elevations of aspartate transaminase (AST) and/or alanine transaminase (ALT); monitor liver function monthly in patients less than 1 year old. Hypersensitivity Reactions: If serious hypersensitivity reactions occur, discontinue and institute appropriate medical therapy. Renal Toxicity: Monitor renal function regularly when administering ACTIMMUNE to patients with severe renal insufficiency.