Associated Inosine to interferon: results of a clinical trial in multiple sclerosis

Background: Uric acid (UA) could act as a natural peroxynitrite scavenger with antioxidant properties. It has been proposed that hyperuricemia might protect against multiple sclerosis (MS). Methods: Patients with relapsing-remitting MS starting treatment with interferon beta-1a 44 μg sc 3/week were randomly assigned to receive either inosine 3 g/day or placebo in a double-blind manner. Follow-up was 12 months. Outcome measures were adverse events and UA laboratory results. Secondary end point was clinical and radiological activity of MS. Relapse rates, percentage of patients without relapses, and progression to secondary MS (SPMS) were assessed. Results: Thirty six patients were included. Two patients in the inosine group showed UA serum level above 10 mg/ml, and symptoms derived from renal colic not leading to hospital admission. Ten additional patients had asymptomatic hyperuricemia (>7 mg). Efficacy parameters (clinical and radiological) were similar between groups. No patient progressed to SPMS Conclusions: Inosine administration was associated with hyperuricemia and renal colic with no additional effect on MS. We cannot conclude inosine is a safe and well-tolerated drug. Doses of around 2 g/day may be more appropriate for future trials.