Multi-center, multi-national, double-blind, randomized, active-controlled (MTX), 3-month study with 4 doses of CH-4051 (0.3 mg, 1.0 mg, 3.0 mg and 3.0 mg with 1mg of folic acid supplementation p.o. daily) compared to a standard dose of MTX at 20 mg per week with 1 mg of folic acid supplementation p.o. daily. This study will be conducted in two parts:~Part A: Patients will be randomized to 0.3 mg CH-4051, 1.0 mg CH-4051 or MTX. Part B: Patients will not be randomized into Part B until the Data Monitoring Committee has reviewed safety data from the Part A when approximately 25 patients (10 patients in each CH-4051 dose groups and 5 patients in the MTX groups) have completed 3 months of treatment. At this time the DMC will make a recommendation whether or not to commence randomization to 3.0 mg CH-4051, 3.0 mg CH-4051 with 1.0 mg of folic acid.
The purpose of this study is to determine if CH-4051 is a safe and effective treatment for rheumatoid arthritis.