Merck Serono, a division of Merck KGaA, Darmstadt, Germany, has announced that the Clarity Phase III pivotal trial of its proprietary oral formulation of cladribine met the two-year primary endpoint of clinical relapse rate reduction in patients with relapsing-remitting multiple sclerosis.
According to the company, the two cladribine tablet treatment groups of the study, assessing different dose regimens, demonstrated a statistically significant reduction in the annualized rate of relapses compared to placebo.
Patients from the lower total dose group experienced a 58% relative reduction in annualized relapse rates with respect to placebo (0.14 versus 0.33 for the placebo group; p<0.001). Patients from the higher total dose group experienced a 55% relative reduction in annualized relapse rates with respect to placebo (0.15 versus 0.33; p<0.001), the company said.
Secondary endpoints of the Clarity study were also met, including reduction of lesion activity as measured by magnetic resonance imaging, proportion of subjects relapse-free and disability progression.
Overall, the frequencies of adverse events were low in the cladribine tablet treatment groups and were comparable to that observed in the placebo group. Lymphopenia, an expected event based on the presumed mechanism of action of cladribine, occurred more frequently in the cladribine tablet treatment groups, the company added.
The Clarity study was a two-year (96 weeks), randomized, double-blind, placebo-controlled, international trial. It enrolled 1,326 patients with relapsing-remitting multiple sclerosis according to the revised McDonald criteria. Study participants were randomized to one of three different treatment groups consisting of two different dose regimens of cladribine tablets or matching placebo tablets (1:1:1 ratio). The primary endpoint of the Clarity study was the qualifying relapse rate at 96 weeks.
Elmar Schnee, president of Merck Serono, said: Based on the successful completion of the Clarity study, we plan to submit cladribine tablets for registration to the EMEA and to the FDA for mid-2009.