Stopping Ozanimod: Large Trial Follow-Up Finds Relapses Return Mildly, With No Sign of Rebound

For people living with relapsing multiple sclerosis, one of the most anxious moments in treatment comes not when a drug is started, but when it is stopped. A class of medications called sphingosine 1-phosphate receptor modulators has transformed care in recent years, yet a lingering fear shadows every discontinuation decision: the possibility of rebound, an explosive return of disease activity that can exceed anything the patient experienced before treatment. Now, one of the largest analyses of its kind has examined what actually happens when patients come off ozanimod, an oral therapy in this class, and the results offer a measure of reassurance grounded in hard data.

The study, published in Annals of Clinical and Translational Neurology, drew on participants from DAYBREAK, a phase 3 open-label extension trial that followed adults with relapsing forms of multiple sclerosis who had previously completed earlier ozanimod trials. Across the parent trials and the extension, participants accumulated up to 117.2 months, nearly a decade, of cumulative exposure to the drug. Of the 2,494 people who entered DAYBREAK, nearly 80 percent completed the study. The researchers focused on 1,679 participants who had at least one day of post-treatment safety follow-up and who did not transition to commercial ozanimod within 14 days of stopping the study drug, creating a window in which any returning disease activity could be observed.

The headline finding is striking in its simplicity: only 55 participants, or 3.3 percent of the analysis population, experienced an objectively confirmed relapse after permanently discontinuing ozanimod. When suspected relapses that failed to meet strict objective criteria were included, the figure rose only slightly, to 4.1 percent. Given that multiple sclerosis is, by its nature, a relapsing disease in these patients, the question the investigators set out to answer was not merely whether relapses occurred, but whether they occurred at a rate and severity beyond what would be expected from the underlying disease simply reasserting itself.

The timing of the relapses tells a story written in pharmacology. Ozanimod works by selectively modulating sphingosine 1-phosphate receptors 1 and 5, trapping lymphocytes inside lymphoid tissues and preventing them from migrating into the central nervous system, where they drive the inflammatory attacks that characterize multiple sclerosis. The drug itself has an elimination half-life of about 21 hours, but its major active metabolite lingers far longer, with a half-life of approximately 11 days. After discontinuation, blood lymphocyte counts return to normal after a median of 30 days, with 80 to 90 percent of patients back in the normal range within three months. True to that pharmacokinetic profile, relapses clustered at two to three months after stopping the drug, with a median onset of 61 days and a range of 3 to 141 days.

The granular breakdown is equally informative. Only five participants, 0.3 percent, relapsed within the first 28 days after discontinuation. Another 22 relapsed between days 29 and 60, representing 1.7 percent of those followed that long, and 26 more relapsed between days 61 and 90, or 2.2 percent of participants with follow-up beyond 60 days. Just two participants relapsed after 90 days, one of whom fell within the protocol’s permitted 10-day follow-up window and the other of whom had been nonadherent to follow-up because of COVID-19 travel restrictions. The pattern mirrors the waning of the drug’s immunological grip rather than any paradoxical overshoot.

Severity is where the rebound question is truly decided, and here the data lean strongly toward reassurance. Nearly all post-treatment relapses were judged mild or moderate by the treating investigators: 20 were mild and 34 were moderate, while only a single participant, 1.8 percent, had a relapse classified as severe. Even that case, the investigators concluded, did not represent higher-than-expected disease activity. The participant, a 44-year-old woman with a heavy pre-treatment disease burden, including 70 T2 lesions on MRI and substantial prior relapse activity, had already experienced a severe relapse while still taking ozanimod roughly a year before the post-treatment episode. Her disability worsened from an Expanded Disability Status Scale score of 7.5 to 8.0, she was not hospitalized, and she achieved partial recovery within 36 days.

Recovery outcomes across the relapsing group were similarly encouraging. Among the 55 participants with confirmed post-treatment relapse, 76.4 percent had completely recovered by their last safety follow-up, 20 percent had partially recovered, and only two participants had not recovered. Median relapse duration was 22 days, and the median increase in EDSS score at relapse was just one point. Four of the seven participants whose EDSS scores rose by two or more points went on to make complete recoveries. Notably, no MRI scans were performed at the time of relapse, and no tumefactive demyelinating lesions, the dramatic, mass-like brain lesions sometimes seen after fingolimod cessation, were ever reported during or after ozanimod treatment in the entire trial program.

The investigators went further, stress-testing their data against definitions of rebound used in earlier studies. Applying the criteria from the fingolimod FREEDOMS trials, where higher-than-expected disease activity rates of 4.0 and 3.5 percent were recorded but were matched by 4.4 and 4.1 percent in placebo groups, 1.4 percent of the ozanimod analysis population met the threshold. Of the 24 participants qualifying, 14 were hospitalized during relapse, but 11 of those hospitalizations occurred in Eastern Europe, where intravenous steroid treatment for relapses is routinely delivered on an inpatient basis regardless of severity, a practice pattern that inflates hospitalization counts compared with settings like the United States. An informal comparison of EDSS changes during relapse against historical data from untreated patients found no statistically significant difference, further supporting the conclusion that these episodes reflect ordinary disease reactivation, not rebound.

Who relapsed matters as much as how many. Participants who experienced post-treatment relapse were younger, diagnosed with multiple sclerosis at a younger age, and carried greater clinical and radiological disease burden, with more gadolinium-enhancing and T2 lesions at baseline and more relapses both during the trials and in the year before discontinuation. A multivariable logistic regression model identified three nominally significant predictors: younger age at diagnosis, a higher number of relapses during the extension trial, and a higher T2 lesion count at parent-trial baseline. This aligns with a consistent theme in the literature, that patients with more active disease before or during treatment face greater risk of relapse after stopping any disease-modifying therapy, and with the well-documented observation that relapse rates in multiple sclerosis peak in the twenties and thirties before declining with age.

The study’s limitations deserve honest acknowledgment. DAYBREAK was not designed to assess post-treatment relapse, the analysis is exploratory and post hoc, and the reported P values are nominal rather than confirmatory. Roughly one-fifth of the overall population lacked safety follow-up and was excluded, though their characteristics resembled those analyzed. About a quarter of the analysis population had fewer than 29 days of follow-up, meaning some relapses may have occurred after observation ended, and the strict requirement for objective neurological worsening may have undercounted milder episodes. The absence of MRI data limits conclusions to clinical activity. Still, the authors’ conclusion stands on a large, systematically assessed dataset: no case showed a pattern suggestive of rebound, and the return of disease activity after stopping ozanimod appears milder and less frequent than that reported after discontinuing natalizumab, where rebound rates of 8 to 22 percent have been reported, or fingolimod, where observational studies have ranged as high as 42.8 percent under varying definitions. For clinicians and patients weighing discontinuation, whether for family planning, side effects, or waning benefit, the message is clear: relapses cluster two to three months after the last dose, are usually mild to moderate, and usually resolve completely, which argues for prompt switching to another therapy and careful monitoring rather than fear of a pharmacological storm.

Subject of Research: Relapse activity and rebound risk after discontinuation of the multiple sclerosis therapy ozanimod in the DAYBREAK open-label extension trial

Article Title: Multiple Sclerosis Relapse Activity After Ozanimod Discontinuation in DAYBREAK Trial Participants

Article References: Gold, R., Selmaj, K. W., Berkovich, R., Cohen, J. A., Comi, G., Havrdová, E. K., Sheffield, J. K., Desai, H., Cheng, C.-Y., Riolo, J. V., Thorpe, A., DeBoer, E., & Cree, B. A. C. (2026). Multiple Sclerosis Relapse Activity After Ozanimod Discontinuation in DAYBREAK Trial Participants. Annals of Clinical and Translational Neurology, 13(10), 2017-2026. https://doi.org/10.1002/acn3.70366

Image Credits: AI Generated

DOI: 10.1002/acn3.70366

Keywords: multiple sclerosis, ozanimod, DAYBREAK trial, rebound, disease-modifying therapy, S1P receptor modulator, relapse, fingolimod, natalizumab, lymphocytes, pharmacokinetics, neurology