Background and importance Fampridine is the only pharmacological agent approved for walking impairment in multiple sclerosis (MS). Medication persistence is an important element in determining the success of any long-term therapy and real-life utilisation data are especially important to optimise resources.

Aim and objectives To evaluate the persistence of fampridine in MS patients, reasons for discontinuation and the influence of predictive factors.

Material and methods Observational, retrospective, longitudinal study. All adults with MS treated with fampridine were included. Persistence, defined as the duration of time from initiation to discontinuation of therapy, was calculated as the count of days from the index prescription to the date of the final dispensing or end of the observation period (August 2021). Persistence after the first year of treatment was also assesed.

Sociodemographic and clinical factors (age, age of diagnosis, DM phenotype, baseline Expanded Disability Status Scale (EDDS), treatment with disease-modifying therapies (DMTs) and anti-spasticity agents and walking support request) were collected from medical record. Persistence and adherence (measured as medication possession ratio (MPR)) data were collected from drug dispensation records (FarmaTools).

For the analysis of persistence a survival analysis with the Kaplan-Meier estimator was performed. Influence of covariates was evaluated according to a Cox regression model. All statistical analyses were performed using SPSS V24.0. Significance level was 0.05.

Results Fifty-one patients were included. Mean±SD age of MS diagnosis was 37.3±12.6 years. 62.7% female. At the start of the treatment, mean±SD age was 49.7±10.0 years. Phenotypes were relapsing-remitting (49%), secondary progressive (41.2%) and primary progressive (9.8%). 68.6% were on treatment with DMTs and 60.8% with anti-spasticity agents. 58.8% required support to walk. Baseline EDDS was 5±1.3. Median adherence in first year was 98.5±4.5%.

Median persistence duration was 1.756 days (95% CI 1.405 to 2.107). Median time to suspension was 84 days (IQR 28–262). Medication suspension rate in first year was 31.4% and overall medication suspension rate was 13/100 patients-year (95% IC 8.1 to 17.9). Discontinuation reasons were lack of efficacy (57.9%), adverse effects (23.1%) or both (14.3%). Cox model showed only influence of age of DM diagnosis HR=1.05 (95% CI 1.01 to 1.07; p=0.007).

Conclusion and relevance A high percentage of patients abandon treatment with fampridine, mainly due to lack of efficacy. Most discontinuations occur in the first year of treatment.

Conflict of interest No conflict of interest