We conducted a post hoc analysis in a subgroup of patients from the ongoing, open-label, 96-week EVOLVE-MS-1 (NCT02634307) study who had brain volume measurements at baseline, Wk48, and Wk96. Baseline normalized brain volume was used to calculate PBVC at Wk48 and Wk96. Confirmed Disability progression (CDP) was measured using the Expanded Disability Status Scale (≥1.5-, ≥1.0-, or ≥0.5-point increase from a baseline score of 0, 1.0-5.5, or 6.0, respectively), with changes sustained for 12 weeks. Estimated proportion of patients with CDP was calculated by the Kaplan-Meier method. No evidence of disease activity (NEDA)-3 was defined as no relapses, no 12-week CDP, and no new/enlarging T2 or new gadolinium-enhancing lesions.

A total of 365 patients were included in this analysis as of 2 July 2019. Median (range) exposure was 96 (75-100) weeks. Mean (SD) PBVC was -0.36 (0.60) from baseline to Wk48 and -0.35 (0.55) from Wk48 to Wk96. Estimated proportion of patients who were free of CDP was 94.3% at Wk48 and 90.7% at Wk96. The proportion of patients with NEDA-3 at Wk48 and Wk96 was 44.7% (163/365) and 25.2% (91/361), respectively.

Interim findings from the ongoing EVOLVE-MS-1 study demonstrate that yearly PBVC in DRF-treated patients approached the rate observed in healthy adults and was consistent with previous studies of DMF. Most patients remained free of CDP at 2 years.