Single-Center 8-Years Clinical Follow-Up of Cladribine-Treated Patients From Phase 2 and 3 Trials.

Background:Cladribine is approved for the treatment of highly-active relapsing multiple sclerosis (MS), where it is also effective on disability progression. In the present single-center study, we aim to report on the 8-years clinical follow-up of 27 patients included in phase 2 and 3 clinical trials for cladribine. Methods:We included patients exposed to cladribine (n= 13) or placebo (n= 14) in ONWARD, CLARITY, and ORACLE-MS trials, and followed-up at the same center after trial termination. Outcomes of long-term disease progression were recorded. Results:During 8-year follow-up, patients treated with cladribine presented with reduced risk of EDSS progression (HR = 0.148; 95%CI = 0.031, 0.709;p= 0.017), of reaching EDSS 6.0 (HR = 0.115; 95%CI = 0.015, 0.872;p= 0.036), and of SP conversion (HR = 0.010; 95%CI = 0.001, 0.329;p= 0.010), when compared with placebo. Conclusions:Our exploratory study provides additional evidence that cladribine may be useful to prevent or, at least, mitigate the risk of disability progression after 8 years.