Durability of no evidence of disease activity-3 (NEDA-3) in patients receiving cladribine tablets: The CLARITY extension study

Background: No evidence of disease activity (NEDA-3) is a patient-centric outcome increasingly used as the goal of multiple sclerosis treatment. Objective: Determine treatment durability of cladribine tablets beyond 2 years considering the variable bridging interval of 0.1-116.0 weeks between CLARITY and CLARITY Extension. Methods: Between CLARITY and CLARITY Extension, patients transitioned from cladribine tablets 3.5 mg/kg to placebo (CP3.5 group, n = 98) or continued further treatment with cladribine tablets 3.5 mg/kg (CC7.0 group, n = 186). Treatment assignment was randomized and blinded in both CLARITY and CLARITY Extension. Results: The 2-year NEDA-3 in CLARITY Extension (encompassing both years of CLARITY Extension) was 29.6% in the CP3.5 group and 32.8% in the CC7.0 group. There was no evidence that treatment effect differed with varying bridging intervals. For patients in the CP3.5 group with a bridging interval of <= 48 weeks, 1 year NEDA-3 (the first year of CLARITY Extension) was 44.4% (28/63) compared with 31.4% (11/35) in patients with a bridging interval of >48 weeks. Conclusion: Treatment with cladribine tablets in CLARITY, followed by either placebo or cladribine tablets in CLARITY Extension, produced sustained benefits for NEDA-3 and its constituent elements for a follow up period up to 6 years from CLARITY baseline.