Switching from anti-CD20 therapies to cladribine and vice versa - Analysis of a German relapsing multiple sclerosis cohort.

Anti-CD20 antibodies and cladribine are established therapies for active relapsing multiple sclerosis (RMS). Increasing evidence suggests that switching between these therapies may be beneficial in patients with ongoing disease activity under current treatment. In this multicenter retrospective study across six German MS centres, a total of 90 patients with active RMS were considered for inclusion, of whom 71 patients were switched either from anti-CD20 antibodies to cladribine (n ​= ​31) or from cladribine to anti-CD20 antibodies (n ​= ​40), with a minimum follow-up of 12 months. At treatment initiation, patients switching from anti-CD20 antibodies were older, had a longer disease duration, and a higher disability score compared to those switching from cladribine (p ​= ​0.0040, p ​= ​0.0447, p ​= ​0.0028, respectively). The primary reason for switching was disease activity. Following the switch, the proportion of patients with relapsing disease activity was markedly reduced (from 55 ​% to 16 ​% for anti-CD20 to cladribine, and from 83 ​% to 25 ​% for cladribine to anti-CD20). Clinical outcomes improved, while serum biomarkers such as neurofilament light chain and glial fibrillary acidic protein remained stable over six months. Notably, the prevalence of hypogammaglobulinemia decreased after switching from anti-CD20 therapies to cladribine. These results indicate that patients with active RMS can achieve clinical stabilization after switching therapies in either direction, underscoring the complementary mechanisms of action and the safety of such an approach in real-world practice.