Suppression of acute experimental allergic encephalomyelitis with a small molecule inhibitor of α4 integrin

Purpose: To determine the efficacy of a small molecule inhibitor of α4 integrin (CT301) at reversing the clinical, pathological and MR- detectable deficits associated with the acute phase of experimental allergic encephalomyelitis (EAE). Materials and methods: EAE was induced in 36 female Hartley guinea pigs, and the treatment period was from day 11 to day 17 post-immunization. Animals received either saline (n=12), anti-α4 integrin antibody (AN100226m; n=12) or CT301 (n=12). T2-weighted fast spin echo and T1-weighted pre- and post-contrast scans were performed at the beginning (day 11) and end (day 18) of the treatment period, and scored for cerebral inflammation and gadolinium enhancement. T1-weighted images were further analyzed to quantify this enhancement as a measure of blood-brain barrier integrity. Dissected CNS was evaluated for inflammation and demyelination. Results: CT301 successfully reversed two clinical indicators of disease over the course of the treatment period. These animals showed decreased T2-weighted abnormalities, as well as a reduction in gadolinium leakage on T1-weighted images. Meningeal and perivascular inflammation was decreased by anti-α4 integrin treatments. Conclusion: CT301 effectively reverses the clinical, pathological and MR-detectable deficits of acute EAE, and may therefore be a promising therapeutic agent in multiple sclerosis (MS).