1Helmut Butzkueven, 2Tim Spelman, 3Suzanne Hodgkinson, 4Sara Eichau Madueño, 4Guillermo Izquierdo, 5Katherine Buzzard, 5Olga Skibina, 1Anneke Van Der Walt, 6Tomas Kalincik, 7François Grand-Maison

1Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia; 2MSBase Foundation, Alfred Centre, 99 Commercial Road, Melbourne, Australia; 3Liverpool Hospital, Sydney, Australia; 4Universitary Hospital Virgen Macarena, Seville, Spain; 5Box Hill Hospital, Melbourne, Australia, Melbourne, Australia; 6MS Centre, Department of Neurology, Royal Melbourne Hospital, Melbourne, Australia; 7Neuro Rive-Sud, Greenfield Park, Canada


Cladribine tablets are approved for relapsing multiple sclerosis (RMS) treatment in many jurisdictions. MSBase investigators are committed to characterizing real-world longitudinal treatment outcomes using this registry data. The objective of this study was to describe cladribine treatment outcomes in the MSBase cohort. These include baseline characteristics, treatment pathways, discontinuation rate, and relapse outcomes.

Material(s) and Method(s):

We extracted data from the MSBase registry for all patients with a confirmed diagnosis of MS who were newly treated with cladribine tablets. Descriptive statistics were used to analyse baseline patient characteristics recorded within 3 months prior to cladribine tablets initiation, including demographics, disease course and duration, prior disease-modifying therapies (DMT), and Expanded Disability Status Scale (EDSS). Relapse and discontinuation outcomes were described in patients with a minimum 6-month observation period.


As of 3rd March 2021, a total of 782 patients, predominantly from Australia, Canada and Spain, were included. From those, 696 were relapsing-remitting MS (RRMS) patients. The median age of cladribine tablets start was 43.8 years and median disease duration was 11.8 years. Median EDSS at cladribine initiation was 2 (IQR 1.5,4). Overall, 13.3% of all RRMS patients initiated cladribine tablets as first-line therapy. Of all RRMS patients switching to cladribine tablets with a treatment gap of <6 months, the most common immediate prior DMT was fingolimod (15%), followed by natalizumab (10%) and teriflunomide (9.5%). Total follow-up time was 629 patient-years. Annualized relapse rate (ARR) on cladribine tablets was 0.11 (95% confidence interval [CI]: 0.09-0.14) compared to a 12-month pre-cladribine ARR of 0.41. Treatment persistence was 96% at 12 months (95% CI: 0.94-0.98) and 90% after 24 months (95% CI: 0.85-0.94).


The growing MSBase real-world cladribine tablets cohort shows excellent outcomes to date. The most common switches to cladribine are from other high-efficacy DMTs such as natalizumab or fingolimod. The annualized relapse rate on treatment is 0.11, consistent with clinical trial data. The observed discontinuation rate over 24 months is very low, at 9%.