Relapsing-Remitting Multiple Sclerosis Benefits From Early Treatment With Cladribine

White Matter Hyperintensities vs MS
White Matter Hyperintensities vs MS
Early treatment with cladribine in MS may help keep patients relapse-free with little to no progression in disability.

Patients with multiple sclerosis treated with cladribine tablets for 2 years followed by placebo for an additional 2 years experience similar clinical benefits and lower risk for clinical worsening compared with patients treated with cladribine only for all 4 years, according to findings of an extension study published in Multiple Sclerosis Journal.

In this extension study of the CLARITY trial, a total of 806 patients with normal lymphocyte counts were provided a new treatment regimen. Participants who received placebo in the CLARITY trial now received 3.5 mg/kg cladribine tablets, whereas those who previously received cladribine were randomly assigned to either 3.5 mg/kg cladribine tablets or placebo.

Patients receiving cladribine tablets had higher lymphopenia grade ≥3 rates than the placebo group; however, overall adverse events were similar between groups. 

More than 90% of patients treated with 3.5 mg/kg cladribine and approximately 100% of those in the placebo group recovered to grade 0 to 1 by the end of the extension study.

Investigators found that patients who had previously taken cladribine in the CLARITY trial for 2 years maintained clinical efficacy improvements during 2-year treatment with placebo in the extension. Additionally, approximately 75% of those receiving placebo in the extension study who had received 3.5 mg/kg cladribine in the preceding trial were free from relapse at study end.

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According to the researchers, this extension study failed to power for efficacy analyses. The investigators also note that there was a variable gap between the CLARITY and extension study, which may further limit the findings.

Despite these limitations, this study demonstrates that the “short-duration posology and favorable risk-benefit profile of cladribine tablets treatment may facilitate treatment adherence, a significant challenge for patients with MS.”


Giovannoni G, Soelberg Sorensen P, Cook S, et al. Safety and efficacy of cladribine tablets in patients with relapsing-remitting multiple sclerosis: Results from the randomized extension trial of the CLARITY study [published online August 1, 2017]. Mult Scler. doi:10.1177/1352458517727603