Impact of Continuous Ofatumumab Exposure During Pregnancy in Multiple Sclerosis

Anti-CD20 therapies are highly effective treatment options for patients with multiple sclerosis (MS), an inflammatory disorder of the CNS commonly affecting women of childbearing age. Anti-CD20 therapies are however unlicensed for use in pregnancy. Belonging to the IgG1 family, anti-CD20 monoclonal antibodies are likely to cross the placenta, especially after the 20th week of gestation. Our objective was to analyze the impact of ofatumumab (OFA), a subcutaneous anti-CD20 monoclonal antibody, during pregnancy.

We present the case of a woman with MS who accidentally administered OFA every 4 weeks until delivery. In addition to detailing the clinical and laboratory outcomes of both mother and child, we provide a summary of the available evidence regarding anti-CD20 treatment during pregnancy and breastfeeding.

Our patient gave birth to a healthy girl between estimated gestational weeks 32-35. Notably, at 3 months postpartum and 4 months after the last OFA administration, the mother remained fully B-cell depleted while the B-cell counts of the child were within the normal range.

Further data are necessary to confirm that OFA treatment during pregnancy does not affect neonatal B cells.