Elisabeth Maillart

Background: Late-onset neutropenia (LON), defined as an absolute neutrophil count (ANC) < 1500/mm 3 that develops between 4 weeks and 6 months after the last drug administration, is a rare side effect of anti-CD20 drugs including ocrelizumab. Although continuation of ocrelizumab after LON is not contraindicated, the risk of LON recurrence is not well known. Cases: We report three cases of recurrent symptomatic agranulocytosis (ANC < 500/mm 3 ) occurring under ocrelizumab. Conclusion: Given the risk of recurrence of symptomatic agranulocytosis and the availability of other treatments, a therapeutic switch may be discussed after the first episode of LON.