Abstract Background Evidence for disease-modifying therapies in patients with multiple sclerosis (MS) aged over 50 years is limited because this population is often excluded from randomized trials. With aging, MS increasingly reflects progression independent of relapse activity (PIRA), while adverse event risk increases. Cladribine is an immune reconstitution therapy with established efficacy in younger populations, but real-world data in older patients, particularly after prior high-efficacy therapies, are scarce. Methods We conducted a prospective observational study of 95 patients aged over 50 years with active MS treated with cladribine at a tertiary MS center in Giessen, Germany. Patients were stratified by prior therapy (treatment-naïve, platform therapy, high-efficacy therapy). Outcomes included relapses, MRI activity, confirmed disability worsening (CDW), confirmed disability improvement (CDI), no evidence of disease activity (NEDA-3/4), lymphocyte dynamics, adverse events, and serum neurofilament light chain (NfL). Results Mean age was 55.9 ± 4.1 years, baseline EDSS was 2.5 ± 1.0. Total follow-up duration was 137 patient-years. Annualized relapse rate decreased from 0.66 before treatment to 0.044 during follow-up. Six relapses and six new T2 lesions (each 6.3%) occurred during follow-up. CDW was observed in 10 patients (11.8%), while 21 patients (24.7%) showed sustained CDI. NEDA-3 was achieved by 66 patients (77.6%) and NEDA-4 by 65 patients (76.5%). No clear differences between prior-treatment groups were observed. Serum NfL levels decreased during treatment. Lymphopenia was predominantly grade I–II. Infections were infrequent (27.4%) and mostly mild. Conclusions Cladribine showed sustained effectiveness and an acceptable safety profile in MS patients over 50 years.
Axhausen et al. (Tue,) studied this question.