Hence, the effect of Bcat1 inhibition on collagen-induced arthritis (CIA) in mice was examined prophylactically, by administering 720 mg kg−1 ERG240 at the time of the booster injection 21 days after the initial immunization, and therapeutically, by administering 1000, mg kg−1 ERG240 after arthritis was established. The gene discussed is BCAT1; the disease is arthritic joint disease.