Abstract
BACKGROUND: A number of elements of the pivotal 'cladribine tablets treating multiple sclerosis orally' (CLARITY) trial have remained unpublished. OBJECTIVE: To report the impact of cladribine on health-related quality of life (QoL) in people with relapsing multiple sclerosis (pwRMS). METHODS: QoL data from the phase III trial of two different doses (3.5 and 5.25 mg/kg) of oral cladribine in pwRMS were acquired from the European Medicines Agency through Freedom of Information. Spearman's rank correlation was used to analyse the relationship between baseline QoL scores and baseline Expanded Disability Status Scale (EDSS) scores. Responses of the Euro Quality of Life 5 Dimensions (EQ-5D) and Multiple Sclerosis Quality of Life-54 (MSQOL-54) questionnaires were compared between treatment and control groups using univariate analyses of covariance. RESULTS: In total, n = 5148 EQ-5D responses and n = 894 MSQOL-54 physical, mental health and dimension scores were extracted. Baseline EQ-5D indices correlated with EDSS scores. After 2 years, pwRMS taking 3.5 ( p = .001) and 5.25 mg/kg ( p = .022) reported significantly improved EQ-5D index scores compared with placebo. Positive, yet non-significant, differences were detected in MSQOL-54 scores between cladribine and placebo. CONCLUSION: Analysis of the CLARITY dataset suggests that, over and above its established clinical efficacy, cladribine leads to improved QoL over 96 weeks. ClinicalTrials.gov identifier: NCT00213135.