DHODH and rheumatoid arthritis: Leflunomide, an immunomodulatory drug primarily prescribed for rheumatoid arthritis and psoriatic arthritis, has seen a resurgence in research interest due to its potential anticancer properties.102 Mechanistically, the metabolic effects of leflunomide stem from its active metabolite, A77 1726, which inhibits the mitochondrial enzyme dihydroorotate dehydrogenase (DHODH).