Analysis of frequency and severity of relapses in multiple sclerosis patients treated with cladribine tablets or placebo: The CLARITY and CLARITY Extension studies
Related Experiment Video
Updated: Nov 6, 2025

A Method of Trigonometric Modelling of Seasonal Variation Demonstrated with Multiple Sclerosis Relapse Data
Published on: December 9, 2015
Nicola De Stefano1, Maria Pia Sormani2, Gavin Giovannoni3
1Department of Neurological and Behavioural Sciences, University of Siena, Siena, Italy/Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy.
Background:
In the CLARITY (CLAdRIbine Tablets treating multiple sclerosis orallY) study of patients with relapsing-remitting multiple sclerosis, treatment with cladribine tablets 3.5 mg/kg (CladT) significantly reduced the annualised relapse rate (ARR) versus placebo; this effect was sustained in CLARITY Extension, without further treatment.
Objective:
To assess the frequency and severity of relapses in patients treated with CladT versus placebo in CLARITY over 2 years and evaluate the durability of effect in patients who received no further treatment for 2 years in CLARITY Extension.
Methods:
In this post hoc analysis, ARRs were calculated for qualifying and all relapses, and qualifying and all severe relapses (i.e. requiring steroid treatment or leading to hospitalisation) in patients treated with CladT (n = 433) and placebo (n = 437) in CLARITY, and those from the CladT group who received placebo in CLARITY Extension (n = 98).
Results:
At Month 6, Year 1 and Year 2, patients receiving CladT had a significantly lower risk of qualifying or all relapses (all p < 0.0001), and qualifying or all severe relapses (all p < 0.005), compared with placebo. This effect was sustained in CLARITY Extension without further treatment.
Conclusion:
The results show durable efficacy of cladribine tablets 3.5 mg/kg for reducing frequency and severity of relapses in patients with relapsing-remitting multiple sclerosis.CLARITY: NCT00213135; CLARITY Extension: NCT00641537.
More Related Videos
11:35The Multiple Sclerosis Performance Test MSPT: An iPad-Based Disability Assessment Tool
Published on: June 30, 2014
06:14Optimized LC-MS/MS Method for the High-throughput Analysis of Clinical Samples of Ivacaftor, Its Major Metabolites, and Lumacaftor in Biological Fluids of Cystic Fibrosis Patients
Published on: October 15, 2017
Related Concept Videos
Bioavailability Study Design: Single Versus Multiple Dose Studies
Drugs for Treatment of Crohn's Disease in IBD Using Glucocorticoids
Clinical Trials: Overview
Drugs for Treatment of Crohn's Disease in IBD Using Biologic Agents: Anti-TNF
Bioavailability Study Design: Healthy Subjects Versus Patients
Drug Accumulation During Multiple Dosing: Intermittent IV Infusions