Furthermore, the controlled trial of slowing of kidney disease progression from the inhibition of xanthine oxidase (CKD-FIX), a large randomized controlled trial enrolling patients with stage 3 or 4 CKD, demonstrated that allopurinol treatment failed to slow eGFR decline over two years compared to placebo, despite a sustained reduction in serum uric acid [58]. The gene discussed is XDH; the disease is chronic kidney disease.