Glatiramer acetate (Copaxone)

Glatiramer acetate (Copaxone) is a novel preparation of synthetic peptides composed of four amino acids. Laboratory studies have shown that it prevents, or modifies, experimental allergic encephalomyelitis, the animal model for multiple sclerosis (MS), in several mammalian species. Its mode of action has not been fully elucidated but it is known to induce suppresser T-cells, known to be deficient in MS, and competitively inhibits the effect of CNS myelin antigens, thought to be important in the pathogenesis of MS, through MHC blockade. Controlled clinical trials have shown it to improve the natural history of MS by reducing both the relapse rate and the resultant disability. GA shows similar efficacy to interferon-beta (IFN-beta) but with fewer systemic side-effects and appears to be better tolerated by patients. It has thus justified its place in the new era of disease-modifying treatments for MS. While the evidence suggests GA should be considered as first-line therapy in selected patients, its differing mechanism of action also gives patients and doctors the option of an alternative agent when the efficacy of IFN-beta is waning or side-effects predominate.