Trends in the real-world management of patients with active relapsing-remitting multiple sclerosis treated with natalizumab (TYSABRI®) in France: An analysis of the PMSI database over five years (2019-2023).

Several factors are changing the way relapsing-remitting multiple sclerosis (RRMS) is currently managed with natalizumab (NTZ), with increasing use of injections in home hospitalization structures, change in treatment formulation, strategy of use regarding pregnancies and sometimes extending interval dosing (EID) to reduce the risk of adverse events (AEs), notably progressive multifocal leukoencephalopathy (PML).

Objective: To describe changes in the real-world management of people with multiple sclerosis (PwMS) treated with natalizumab in France over the period 2019-2023.

Methods: This is a retrospective observational study using data extracted from the French national hospital database (PMSI) from the first of January 2019 to the 31st of December 2023 including data on all reimbursements of NTZ: patients' demographic characteristics, dates of deliveries and of infusions, formulation of the drug, type of facilities used (acute care, home hospitalization) and eventual pregnancies.

Results: A total number of 5,708 patients treated with NTZ were identified in 2019, increasing to 7,181 in 2023. The age/gender distribution was stable over the period with 76.9% of women and a mean age of 39.9 years (SD 11.40). The number of at home injections increased substantially from 6 in 2019 to 3,501 in 2023, particularly after COVID-19 health care reorganization. Since December 2021, when the NTZ subcutaneous (SC) formulation was launched, the percentage of intravenous infusions decreased from 71.0% in January 2022 to 29.2% in December 2023. Over the whole 5-year period, frequency of using NTZ with EID between 36-42 days increased from 5.9% in 2019 to 17.0% in 2023. Practices changed regarding NTZ and pregnancies since the number of patients with a delivery increased from 117 in 2019 to 179 in 2023. NTZ was stopped in nearly 20% of patients during the three months before conception in 2019 and 7-8% only from 2020. Maintenance of NTZ during the first as well as the second trimester of pregnancy clearly increased over the 2019-2023 period from 75% to 90% in the first trimester and 44% to nearly 78% in the second trimester.

Conclusion: Natalizumab use was maintained and even increased in France over the 2019-2023 period despite enrichment of the therapeutic arsenal for PwMS. It was certainly facilitated by better therapeutic management with the development of at-home injections, simplification of the procedure with the SC formulation, the possibility of EID every 5-6 weeks for the intravenous formulation and better use regarding pregnancies.