phase III trial of Mylinax (oral cladribine)
May 18, 2009
Merck Serono reported positive long-term results from a phase III trial of Mylinax (oral cladribine) for the treatment of multiple sclerosis. This two-year (96-week), randomized, double-blind, placebo-controlled, international trial, dubbed CLARITY (CLAdRIbine Tablets in treating MS orallY),
enrolled 1,326 subjects with relapsing-remitting MS.
During the first year, oral cladribine were given in two or four treatment courses, with each course consisting of once daily administration for four to five consecutive days.
In the second year, two treatment cycles were given to all groups.
The primary endpoint was the qualifying relapse rate at 96 weeks.
Secondary endpoints included MRI endpoints, proportion of subjects qualifying relapse-free and disability progression at 96 weeks.
Two year data demonstrated a statistically significant reduction in the annualized rate of relapses compared to placebo. Subjects in the low-dose cladribine arm 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) while those in the high-dose cladribine arm experienced a 55% relative reduction in annualized relapse rates with respect to placebo (0.15 versus 0.33; p<0.001).
Over the two-year period of the study, 80% of the low dose regimen Cladribine arm and 79% of the high-dose regimen arm experienced no clinical relapse, compared with 61% of the placebo group (p<0.001 for both dose regimens).
Treatment with Cladribine also led to a more than 30% reduction in the risk of disability progression relative to placebo over two-years (low-dose regimen: p≡0.018; high-dose regimen: p≡0.026). In addition, both dose regimens of cladribine demonstrated statistically significant reductions in different types of brain lesions as measured by magnetic resonance imaging (MRI) compared to placebo (reductions ranged from 73% to 88% depending on MRI measure and dose group; p<0.001 for each of these MRI measures and for both dose regimens). Adverse events were similar between the cladribine treatment arms and placebo.