Real-World Clinical Outcomes in Relapsing-Remitting Multiple Sclerosis Patients Who Switch from Natalizumab to Delayed-Release Dimethyl Fumarate

Background: Standardized practices for transitioning patients from natalizumab to delayed-release dimethyl fumarate (DMF; also known as gastro-resistant DMF) are lacking. Clinical practices and switch protocols vary across the population, and predictors of favorable treatment outcomes on DMF following natalizumab are not well understood.

Objectives: Describe the retrospective, observational STRATEGY study of relapsing-remitting multiple sclerosis (RRMS) patients who switched from natalizumab to DMF in the real-world setting. The following factors potentially associated with treatment outcomes on DMF are to be included: patient demographics, disease activity prior to initiating natalizumab or while on natalizumab, duration of washout from natalizumab to DMF, and steroid treatment during washout.

Methods: STRATEGY is being performed through a single time point medical chart abstraction without required study visits or procedures. Approximately 500 patients from approximately 50 United States sites will be enrolled. Key inclusion criteria include age ≥18 years, RRMS diagnosis (McDonald criteria), at least 12 months of continuous treatment with natalizumab monotherapy prior to initiation of DMF, and initiation of DMF at least 12 months prior to enrollment. Patients are eligible to enroll regardless of current DMF use. Endpoints to be examined include relapse activity 12 months after initiation of DMF (measured as proportion of patients relapsed, annualized relapse rate, proportion of patients with MS-related hospitalization, and proportion of patients with relapses requiring intravenous [IV] steroids); association between disease activity prior to initiating natalizumab or while on natalizumab and relapse activity on DMF; association between washout duration and relapse activity on DMF; and association between IV steroid use during the washout period and relapse activity while on DMF.

Results: STRATEGY is ongoing; results will be reported.

Conclusions: STRATEGY is being conducted to examine potential predictors of treatment response to DMF in RRMS patients who switched from natalizumab to DMF in the real-world setting.