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VX-497: a novel, selective IMPDH inhibitor and immunosuppressive agent
J Jain1, S J Almquist, D Shlyakhter
1Cell Biology and Immunology, Vertex Pharmaceuticals Incorporated, 130 Waverly Street, Cambridge, Massachusetts 02139, USA. Jugnu_Jain@vpharm.com
Journal of Pharmaceutical Sciences
|April 5, 2001
Summary
VX-497 is a novel drug that effectively inhibits Inosine monophosphate dehydrogenase (IMPDH), crucial for lymphocyte proliferation. This potent and specific inhibitor shows promise for immunosuppressive therapies by selectively targeting immune cells.
Area of Science:
- Biochemistry
- Immunology
- Pharmacology
Background:
- Inosine monophosphate dehydrogenase (IMPDH) is a key enzyme in purine metabolism, essential for lymphocyte proliferation.
- IMPDH is a validated target for immunosuppressive drugs like CellCept and mizoribine.
Purpose of the Study:
- To characterize the immunosuppressive activity of VX-497, a novel noncompetitive IMPDH inhibitor.
- To evaluate the selectivity and reversibility of VX-497's antiproliferative effects.
Main Methods:
- In vitro assays measuring lymphocyte proliferation inhibition by VX-497.
- Reversal studies using exogenous nucleosides (guanosine, adenosine, uridine).
- In vivo studies assessing antibody response inhibition in mice.
Main Results:
- VX-497 is orally bioavailable and inhibits human, mouse, rat, and dog lymphocyte proliferation at ~100 nM.
- Inhibitory effects are reversed by guanosine, confirming specific IMPDH inhibition.
- VX-497 demonstrates dose-dependent inhibition of antibody response in vivo (ED50 ~30-35 mg/kg).
Conclusions:
- VX-497 is a potent, specific, and reversible inhibitor of IMPDH.
- The drug selectively inhibits lymphocyte proliferation with potential applications in immunosuppression.
- VX-497 exhibits efficacy in vivo, with single daily dosing being as effective as twice-daily dosing.