Multiple Sclerosis Relapse Activity After Ozanimod Discontinuation in DAYBREAK Trial Participants.

Return of disease activity is expected when patients discontinue disease-modifying therapy (DMT) for multiple sclerosis (MS). Some MS DMTs are associated with higher-than-expected disease activity (rebound) after discontinuation. This exploratory analysis assessed disease activity and risk of rebound after ozanimod discontinuation. DAYBREAK (NCT02576717; October 2015-April 2023) was a single-arm, open-label extension trial of ozanimod 0.92 mg/d in participants with relapsing MS who completed phase 1-3 ozanimod trials. Two protocol amendments increased the required safety follow-up from an initial 28 days to 75 and then 90 days. Confirmed post-treatment relapses were characterized. Of 2494 participants, 1679 participants had ≥ 1 day of follow-up and did not initiate commercial ozanimod in 14 days of exiting the trial; 30.6% had 60 days of post-treatment follow-up. Fifty-five participants (3.3%) had known post-treatment relapse. Fifty-four were not taking an MS DMT when they relapsed; one relapsed soon after starting fingolimod. Relapses were associated with Expanded Disability Status Scale (EDSS) score increases of 0-3 points (median 1 point); the participant with the 3-point increase had a moderate relapse and complete recovery in 23 days. Forty-two participants (76.4%) fully recovered, 11 (20.0%) partially recovered, and 2 (3.6%) did not recover. Only one (1.8%) relapse was considered severe by the investigator: EDSS increased from 7.5 to 8.0, and the participant partially recovered within 36 days. Most participants did not relapse within 90 days following ozanimod discontinuation. Post-treatment relapse cases suggestive of a rebound effect were not observed.