Long-term follow-up of patients with relapsing multiple sclerosis from the CLARITY/CLARITY Extension cohort of CLASSIC-MS: An ambispective study

Background: CLASSIC-MS evaluated the long-term efficacy of cladribine tablets in patients with relapsing multiple sclerosis. Objective: Report long-term mobility and disability beyond treatment courses received in CLARITY/CLARITY Extension. Methods: This analysis represents CLASSIC-MS patients who participated in CLARITY with/without participation in CLARITY Extension, and received > 1 course of cladribine tablets or placebo (N = 435). Primary objective includes evaluation of long-term mobility (no wheelchair use in the 3 months prior to first visit in CLASSIC-MS and not bedridden at any time since last parent study dose (LPSD), i.e. Expanded Disability Status Scale (EDSS) score <7). Secondary objective includes long-term disability status (no use of an ambulatory device (EDSS < 6) at any time since LPSD). Results: At CLASSIC-MS baseline, mean +/- standard deviation EDSS score was 3.9 +/- 2.1 and the median time since LPSD was 10.9 (range = 9.3-14.9) years. Cladribine tablets-exposed population: 90.6% (N = 394), including 160 patients who received a cumulative dose of 3.5 mg/kg over 2 years. Patients not using a wheelchair and not bedridden: exposed, 90.0%; unexposed, 77.8%. Patients with no use of an ambulatory device: exposed, 81.2%; unexposed, 75.6%. Conclusion: With a median 10.9 years' follow-up after CLARITY/CLARITY Extension, findings suggest the sustained long-term mobility and disability benefits of cladribine tablets.