Chemical Modification of Natural Human Tumor Necrosis Factor‐α with Polyethylene Glycol Increases Its Anti‐tumor Potency

Abstract

Natural human tumor necrosis factor-alpha (TNF-alpha) was chemically modified with an active ester of monomethoxy polyethylene glycol (PEG). The molecular weight of PEG-modified TNF-alpha depended on the reaction time as well as the initial molar ratio of PEG to TNF-alpha. The specific activity of modified TNF-alpha was gradually reduced with increase in the degree of PEG-modification, but the plasma half-life of TNF-alpha was increased by up to 40-fold. Modified TNF-alpha showed approximately 100 times greater anti-tumor potency than unmodified TNF-alpha. Covalent attachment of PEG to TNF-alpha thus increased the bioavailability of TNF-alpha, and may facilitate its potential therapeutic use.