The recurrence of disease activity after ocrelizumab discontinuation in multiple sclerosis

Ocrelizumab (OCR) is a highly effective treatment of multiple sclerosis (MS), and B cell repopulation profiles suggest that it might be used as an immune reconstitution therapy. However, data on disease recurrence after stopping treatment with OCR are scarce. Our objective was to evaluate the recurrence of disease activity after OCR discontinuation.

In this multicenter retrospective cohort study, we included MS patients who discontinued OCR, without switching to another treatment, for twelve months or more, after having received at least one full dosage of 600 mg. We defined focal inflammation as the occurrence of a clinical relapse or significant MRI activity (≥3 new T2 lesions or ≥2 contrast-enhancing lesions).

We included 53 MS patients; 41 relapsing remitting (RRMS), 5 secondary progressive (SPMS) and 7 primary progressive (PPMS) patients. Median follow-up period after OCR discontinuation was 16 months. We only observed focal inflammation after discontinuation in RRMS patients; 2.4 % (1/41) patients presented with significant MRI activity and matching clinical symptoms, and 7.3 % (3/41) patients presented with a suspected clinical relapse without radiological activity: a total of 9.8 % (4/41) at a median time of 17 months after the last infusion.

We found focal inflammation after discontinuation of OCR in 4 (9.8 %) of the RRMS patients, of which 1 was radiologically confirmed. Our observations highlight that recurrence of focal inflammation seems low but discontinuation may not be appropriate for everyone. Further larger studies are important to determine the immune reconstitution therapy potential of OCR.