Description:
IC50 Value: N/A
Firategrast is an orally bioavailable alpha4 beta1/alpha4 beta7 integrin antagonist designed to reduce trafficking of lymphocytes into the central nervous system (CNS). 
in vitro: N/A
in vivo: Median (n, range) CSF lymphocyte counts (cells/?l) at weeks 0, 24, 28 and 36 were: 5.3 (44, 0.3-70.2), 3.3 (31, 0.0-99.0), 3.0 (32, 0.0-58.2) and 3.5 (29, 0.0-274.8). CD4+, CD8+ T- and CD19+ B-lymphocyte counts followed a similar pattern. Minimal changes were observed for CD3-CD16+CD56+ natural killer cells. Median CD4 : CD8 ratios were: 2.9 (41, 1.1-10.9), 2.2 (29, 0.6-5.9), 3.8 (28, 1.6-9.0) and 3.8 (21, 2.1-9.4). Blood lymphocyte counts were elevated at weeks 4 and 24, consistent with the mechanism of firategrast, and returned to baseline when firategrast was discontinued [1].
Toxicity: Firategrast was generally well tolerated at all doses. The frequency of all adverse events was similar across all treatment groups except for an increased rate of urinary tract infections in the high-dose firategrast group. No cases of progressive multifocal leukoencephalopathy or evidence of reactivation of JC virus were identified [2].
Clinical trial: Study Of White Blood Cells In The Cerebrospinal Fluid And Blood Of Patients With Relapsing Forms Of Multiple Sclerosis. Phase 2