DX09
The Safety and Efficacy of Switching from Natalizumab to Dimethyl Fumarate: Real World Experience
Natalizumab (NAT) is a monoclonal antibody which prevents entry of leukocytes into the CNS. This mechanism of action has made it one of the most effective therapies against MS. However, NAT’s use is limited by its risk of progressive multifocal leukoencephalopathy (PML). Moreover, switching from NAT to another therapeutic agent is made even more complex as there is an increased risk of rebound inflammation. Dimethyl fumarate (DMF) is a new oral agent which offers a therapeutic alternative to patients stopping NAT. However, the safety and efficacy of this switch has not yet been studied.
Objectives: To assess the stability of patients switched from NAT to DMF. A secondary objective is to search for factors which may predict stability on DMF.
Methods: A telephone survey and chart review was done for 66 RRMS who had been switched from NAT to DMF. Factors analyzed included age, gender, duration on NAT, duration between NAT and DMF and duration on DMF
Results:
A total of 66 patients were surveyed and 47 (71.22%) remained stable when switched to DMF and 19 (28.78%) were found to be unstable on DMF. While the findings were not significant, the following trends were noticed. Female patients were 2.9x more likely to be unstable compared to males. Patients < 60 of age were 1.8x more likely to be unstable compared to patients > 60 years of age. Patients on NAT for < 2 years are 2.4x more likely to be unstable compared to patients on NAT for > 2 years. Patients who have an 8 week or less gap between NAT and DMF are just as likely to develop instability compared to patients with more than an 8 week gap between treatments. Patients who are on DMF for < than 6 months are 0.6x less likely to be unstable than patients on DMF for longer than 6 months. Or in other words, patients on DMF for longer than 6 months are 1.7x more likely to be unstable
Conclusions: A majority of patients remain stable when switching from NAT to DMF. Factors such as sex, age and duration of NAT treatment may predict the probability of a successful transition. An extension of this study will be carried out which will look at MRI changes and relapse rate after a patient has stopped NAT and switched to DMF.