Persistence, Adherence, and Switching to Higher-Cost Therapy in Patients with Multiple Sclerosis Initiating Oral Disease-Modifying Therapies: A Retrospective Real-World Study.

People living with multiple sclerosis (MS for short) can find it difficult to maintain treatment plans. This can impact how well disease-modifying therapies (DMTs) work. This means treatments may not be as effective at controlling symptoms or stopping new symptoms (relapse). In this study, we looked at health records of 6934 previously diagnosed people living with MS in the USA. These people started DMTs for the first time between January and June 2020. Researchers studied how long people continued their treatment (known as persistence) and how often people took their treatment as recommended (adherence). We also studied how many people switched to a more expensive treatment (ocrelizumab, natalizumab, or cladribine). We measured persistence based on how many days people continued their treatment. We measured adherence through the number of people who took their treatment at least 80% of the time. After 1 year, more people who took teriflunomide and fingolimod continued treatment than people on dimethyl fumarate or diroximel fumarate. These people were also more likely to follow their treatment plan. People taking dimethyl fumarate were most likely to switch to a more expensive treatment. On average, people who changed to a more expensive treatment did so after around 8 months. In this study, we found that people with MS who started teriflunomide or fingolimod for the first time were more likely to continue treatment and take treatment as recommended than those on dimethyl fumarate or diroximel fumarate. They also took longer to switch to a more expensive treatment.