Comparative renal excretion of VX-702, a novel p38 MAPK inhibitor, and methotrexate in the perfused rat kidney model.

Context: VX-702 is a novel p38 mitogen-activated protein kinase inhibitor being developed to treat rheumatoid arthritis.

Objective: To characterize the renal excretion profile of VX-702 using the isolated perfused rat kidney (IPRK) model.

Methods: Studies were performed to assess the dose linearity of VX-702 excretion and to evaluate the effect of inhibitors of organic anion (probenecid) and organic cation (cimetidine) transport systems on VX-702 disposition. VX-702 excretion was studied over a range of doses targeting concentrations between 100 and 600 ng/mL. VX-702 (600 ng/mL) was also co-perfused with probenecid (1 mM) and cimetidine (2 mM). The results were compared to parallel experiments performed with methotrexate (MTX).

Results: VX-702 excretion was linear over the range of doses studied, and clearance data were consistent with net reabsorption by the kidney. Transport inhibition studies indicate that VX-702 is not a substrate for renal organic anion and organic cation transport systems. MTX (500 ng/mL) also displayed net reabsorption in the IPRK, but secretory transport was inhibited upon co-administration with probenecid. This finding is consistent with previous IPRK studies that demonstrated inhibitory effects of NSAIDS on MTX excretion.

Conclusion: Overall, this study suggests that a renal drug-drug interaction between VX-702 and MTX would be unlikely if these medications were co-administered.