INDIANAPOLIS—A majority of patients remain stable when switching from natalizumab to dimethyl fumarate, according to data presented at the 2015 CMSC Annual Meeting. Factors such as sex, age, and duration of natalizumab treatment may predict the probability of a successful transition, reported lead author Faria S. Amjad, MD, of Georgetown University Hospital in Washington, DC, and research colleagues.
Natalizumab is a monoclonal antibody that prevents entry of leukocytes into the CNS. This mechanism of action has made it one of the most effective therapies against multiple sclerosis (MS). However, natalizumab’s use is limited by its risk of progressive multifocal leukoencephalopathy (PML). Moreover, switching from natalizumab to another therapeutic agent is made even more complex, as there is an increased risk of rebound inflammation. Dimethyl fumarate is an oral agent that offers a therapeutic alternative to patients stopping natalizumab. However, the safety and efficacy of this switch have not been studied.
To assess the stability of patients switched from natalizumab to dimethyl fumarate, Dr. Amjad and colleagues conducted a telephone survey and chart review for 66 patients with relapsing-remitting MS who had been switched from natalizumab to dimethyl fumarate. Factors analyzed included age, gender, duration on natalizumab, and duration on dimethyl fumarate.
A total of 66 patients were surveyed; 47 (71.22%) remained stable when switched to dimethyl fumarate, and 19 (28.78%) were found to be unstable on dimethyl fumarate. While the findings were not statistically significant, several trends were noted. Female patients were 2.9 times more likely to be unstable, compared with males. Patients younger than 60 were 1.8 times more likely to be unstable, compared with patients older than 60. Patients on natalizumab for less than two years were 2.4 times more likely to be unstable, compared with patients on natulizumab for more than two years. Patients who have an eight-week or less gap between natulizumab and dimethyl fumarate are just as likely to develop instability as patients with more than an eight-week gap between treatments. Patients who are on dimethyl fumarate for less than six months are 0.6 times less likely to be unstable than patients on dimethyl fumarate for longer than six months. In other words, patients on dimethyl fumarate for longer than six months are 1.7 times more likely to be unstable.
According to the researchers, an extension of this study will look at MRI changes and relapse rate after a patient has stopped natalizumab therapy and switched to dimethyl fumarate.