What drives switching between anti-C20 therapies in multiple sclerosis? A single centre audit

<h3>Introduction</h3> Highly effective disease modifying therapies, in Multiple Sclerosis (MS), including anti- CD20 monoclonal antibodies, offer significant improvements in treatment efficacy. Intravenous, hospital administered ocrelizumab (OCR) and subcutaneous, home patient- administered ofatumumab (OFA) are available. <h3>Aim</h3> To describe characteristics of people with MS (PwMS) switching between anti-CD20 therapies in MS. <h3>Methods</h3> Retrospective, single centre, electronic patient record audit. <h3>Results</h3> 18 PwMS were identified, 10 females, mean age 46, (range 23–61), 17 switched from OCR to OFA and 1 vice versa OFA to OCR. Reasons for OCR to OFA switching include; 11 PwMS (65%) due to patient preference, also associated with a higher average distance from centre (37km vs 21km), 10 PwMS (59%) with inadequate suppression of CD19 counts, 4 on standard interval OCR (last CD19 counts mean 110 cells/uL, range 86–174 cells/uL ) and 6 on extended interval OCR (mean monthly interval 9 months, (range 9–11 months) (last CD19 counts mean 186 cells/uL, range 12–771 cells/uL), and 2 patients (12%) due to acute infusion reactions. 1 patient switched (OFA to OCR) due to patient preference. <h3>Conclusions</h3> Patient preference commonly drives anti-CD20 therapy switches and travel distance to the infusion centre may contribute, as well as failure to suppress CD19 counts on OCR.