Merck released Phase III data from two trials for cladribine tablets, demonstrating efficacy in patients with multiple sclerosis.

Data from a two-year Phase III trial and a two-year extension study showed that patients with relapsing MS, who initially received placebo and were switched to cladribine in the extension, had significantly reduced annualized relapse rates and were more likely to be relapse-free at the end of the extension phase. Relapse rates were maintained for patients who received cladribine for two years and were then switched to placebo for two years in the extension phase.

A separate Phase III trial showed that, for patients with a first demyelinating event, treatment with cladribine significantly reduced the risk of progression to clinically definite MS compared with placebo.