Toddlers, Job In Addition To The cdk1 inhibitor Cell Cycle inhibitor

A range of experimental evidence points on the likely use of Syk inhibitors in the treatment of various autoimmune disorders.

In an ovalbumin induced airway inflammation model in the rat, the efficacy of BAY 61 3606, at a dose of 30 mg/kg, b. i. d., in suppressing the accumulation cdk1 inhibitor of eosinophils in BAL fluid was similar to that of 0. 3 mg/kg po, b. i. d., of dexamethasone. The less than adequate pharmacokinetic profile of BAY 61 3606 contributed to the need for the high dose in rats for efficacy of this potent inhibitor of Syk. Compound 13 has been reported to be a potent and selective Syk inhibitor with IC50 _ 41 nM. The compound inhibited the degranulation of RBL 2H3 cells with IC50_460 nM and inhibited the IgE induced passive cutaneous anaphylaxis reaction in mice with ED50_13. 2 mg/kg s. c. R112 and R406, two structurally related analogs, have been reported to be potent, selective, and ATP competitive inhibitors of Syk.

In healthy human volunteers, orally administered R406 was well tolerated, exhibited desirable pharmacokinetic properties, and inhibited baso phil activation and degranulation induced ex vivo by IgE in a dose dependent manner. The lymphocyte specific kinase, belonging to the Src family of tyrosine kinases, is expressed in T cells and natural killer cells and is NSCLC responsible for the activation of and signaling through the T cell receptor. Activation of this cascade results in the upregulation of inflammatory cytokines such as IL 2 and interferon, and ultimately in the activation and proliferation of T lymphocytes to generate an immune response. Therefore, inhibition of Lck is likely to elicit an immunosuppressive effect that could be useful in the treatment of T cell mediated diseases like rheumatoid arthritis, inflammatory bowel disease, psoriasis, and organ graft rejection.

The X ray structure of a close analog of 15 in Lck indicated that the compound binds in the ATP site and that the C H at the 2 position donates an H bond to the carbonyl of Glu317. Compound 16, which is closely related to 15, is a modestly selective inhibitor of Lck with IC50_22 nM.