Introduction <p>Cognitive impairment can affect people with multiple sclerosis (MS) at all stages, negatively impacting their work performance and quality of life. This study aimed to report the cognitive function and employment status data for participants with highly active relapsing MS (RMS) treated with cladribine tablets (CladT) during the 2-year, prospective, open-label, exploratory, single-arm, multicentre, phase IV CLARIFY-MS study.</p> Methods <p>In this post hoc analysis, changes in cognitive function at month (M)12 and M24 (vs baseline) were measured using the Brief International Cognitive Assessment for MS (BICAMS) battery. Additional analyses were conducted to assess clinically meaningful 4- and 8-point changes in Symbol Digit Modalities Test (SDMT) scores. The employment status of participants was determined through a survey at baseline and M24.</p> Results <p>BICAMS parameter scores remained stable over 2&#xa0;years in CladT-treated participants. As determined by a 4- and 8-point change, a high proportion of participants had increased or stable SDMT scores at M24 versus baseline. The mean annualised percentage brain volume change (PBVC) in participants was low. No correlation was found between changes in BICAMS parameter scores and annualised PBVC. Furthermore, no major differences in the employment status of participants were observed over 2&#xa0;years, with &gt; 40% of participants being in full-time employment during the study.</p> Conclusions <p>Most CLARIFY-MS participants had increased or stable information processing speed at M24 (vs baseline), as determined using clinically meaningful 4- and 8-point changes in SDMT scores. Overall, the cognitive function and employment status of CladT-treated participants with highly active RMS remained stable over 2&#xa0;years.</p> Trial Registry Details <p>URL: <a href="https://clinicaltrials.gov/ct2/show/NCT03369665">https://clinicaltrials.gov/ct2/show/NCT03369665</a>; ClinicalTrials.gov Identifier: NCT03369665.</p>