Natalizumab was approved for use in the UK as an intravenous (IV) infusion for rapidly evolving multiple sclerosis in August 2007; with the subcutaneous (SC) formulation available in June 2021. This project aimed to assess changes in patient care in Swansea, since the institution of SC natalizumab, assessing patient satisfaction and unit flow. Anonymous data was collected using a questionnaire completed in December 2021.

Of 78 patients, 64 (82%) had switched to, or started treatment with SC. Average combined infusion and sur- veillance time for IV was 142 minutes, reducing to average 61 minutes for SC. Of 50 SC patients completing questionnaires, 7 reported mild adverse reactions including pain, swelling, nausea and fatigue. 84% of SC patients reported increased convenience and 96% patients were satisfied or very satisfied with switching.

Conclusion Subcutaneous natalizumab is a well-tolerated alternative to the intravenous infusion. In this cohort of patients, the majority were satisfied with switching, finding the SC injection more convenient, although some patients reported more pain especially when delivered in the arm. A major benefit to patients and staff is reduced delivery time, improving access to valuable infusion space. Monitoring will be reduced further to 15 minutes, once patients have received 6 injections.