Ocrelizumab-induced neutropenia: severity, recurrence, and management. A French national pharmacovigilance study

Ocrelizumab, an anti-CD20 monoclonal antibody, has proven effective in reducing relapses and disease progression in multiple sclerosis. While neutropenia is a known adverse effect of anti-CD20 therapies, data on the clinical severity, recurrence risk, and management of ocrelizumab-induced neutropenia (OIN) remain limited.

Describe clinical severity, recurrence risk and management of OIN.

We performed a retrospective observational study based on OIN reports from the French Pharmacovigilance Database. A questionnaire was sent to clinicians who had reported cases. Patients with moderate or severe neutropenia (< 1.0 G/L) were included.

Thirty-four cases of OIN were analysed. Neutropenia was mostly late-onset (>4 weeks post-cycle, 94.1 %) and occurred mainly after the first (32.4 %), second or third cycle (26.5 %). Most patients (55.9 %) were asymptomatic, 32.4 % developed infections and 11.8 % presented agranulocytosis symptoms. Ocrelizumab was reintroduced in 15 patients, with recurrence in 4 cases (26.6 %). Two cases of recurrent neutropenia were reported after switching to ofatumumab.

OIN is an intermittent adverse event, often discovered incidentally and generally not severe. Most cases are likely to go undetected as asymptomatic. With a recurrence rate of 25 %, rechallenging with ocrelizumab should be considered based on MS condition of the patient and available alternative treatment.