Oral cladribine for management of multiple sclerosis–Clinical experience from Hong Kong

Oral cladribine, a selective immune reconstitution therapy, offers a short-course option for disease-modifying therapy (DMT) in multiple sclerosis (MS), a chronic neurodegenerative disease characterized by inflammation and demyelination affecting 2.8 million people worldwide. Despite its proven safety and efficacy in phase 2 and 3 trials, data for oral cladribine treatment in Asian populations remain limited. This case series aims to contribute real-world experience across the clinical spectrum of disease by presenting Asian MS patients treated in Hong Kong. This retrospective case series comprises 9 patients diagnosed with relapsing-remitting MS and received oral cladribine treatment in Hong Kong between 2019 and 2021. These patients, treated in both public and private hospitals, were followed up to assess the outcomes of oral cladribine therapy. Relevant data were extracted from patient's medical records. Outcomes were generally positive, with 6 out of 9 patients showing stable or improved Expanded Disability Status Scale (EDSS) scores 2–4 years after treatment initiation and 7 remaining relapse-free within 2–5 years of treatment initiation. Only 2 patients experienced mild relapses. Follow-up MRI scans revealed no new lesion development in any patient. One case of transient lymphopenia was noted, which did not require discontinuation of treatment. Our clinical experience with these patients aligned with the safety and efficacy outcomes reported in clinical trials. These observations support the efficacy of a short-course regimen in reducing overall treatment burden for patients and potentially improving adherence to therapy. To substantiate and build upon these findings and explore long-term outcomes in larger cohorts, further research and continued monitoring of patients is necessary.