Interferon alfacon-1 is a wholly synthetic type-I interferon. The 166-amino acid sequence of interferon alfacon-1 was derived by scanning the sequences of several natural interferon alpha subtypes and assigning the most frequently observed amino acid in each corresponding position resulting in a consensus sequence. Four additional amino acid changes were made to facilitate the molecular construction, and a corresponding synthetic DNA sequence was constructed using chemical synthesis methodology. Interferon alfacon-1 differs from interferon alfa-2b at 19/166 amino acids (88% homology), and with Interferon alfa-2a at 18/166 amino acids (88% homology). Comparison with interferon-beta shows identity at over 30% of the amino acid positions. Interferon alfacon-1 is produced in Escherichia coli (E. coli) cells that have been genetically altered by insertion of a synthetically constructed sequence that codes for interferon alfacon-1. Prior to final purification, interferon alfacon-1 is allowed to oxidize to its native state, and its final purity is achieved by sequential passage over a series of chromatography columns. This protein has a molecular weight of 19,434 daltons.

INFERGEN is a sterile, clear, colorless, preservative-free liquid formulated with 100 mM sodium chloride and 27 mM sodium phosphate at pH 7.0 ± 0.2. The product is available in single-use vials containing 9 mcg and 15 mcg interferon alfacon-1 at a fill volume of 0.3 mL and 0.5 mL, respectively. INFERGEN vials contain 0.03 mg/mL interferon alfacon-1, sodium chloride (5.9 mg/mL), and sodium phosphate (3.8 mg/mL) in Water for Injection, USP. INFERGEN is to be administered undiluted by subcutaneous injection.^[1]

Adapted from the FDA Package Insert.