Study Finds Monoclonal Antibody Exposure Does Not Negatively Affect Breastfed Infants of Mothers With MS

Multiple sclerosis (MS) is typically diagnosed between the ages of 20 and 40 years, and it affects females at least two to three times more often than males. The disease is not known to affect fertility nor increase the risk of miscarriage. Because the onset of symptoms coincides with the span of reproductive years for females, family planning can present some challenges for people living with MS.

Advances in MS disease management have included the emergence of monoclonal antibodies as effective disease-modifying therapies (DMTs) for MS. FDA-approved treatments include Tysabri (natalizumab), Lemtrada (alemtuzumab), Ocrevus (ocrelizumab), and Kesimpta (ofatumumab).

Although there is evidence that MS disease activity may abate during pregnancy, the risk of relapse increases postpartum. The World Health Organization recommends exclusive breastfeeding for the first six months of a child’s life, and studies have found that doing so may lower the risk of postpartum MS relapses. For mothers seeking to resume their MS DMT after delivery, there is little research to determine whether their treatment is safe to use while breastfeeding. In many cases, patients are advised to discontinue breastfeeding after resuming treatment.

A study led by Laura Witt, Ph.D., from the department of neurology at Ruhr University in Bochum, Germany, looked at data from the German MS and Pregnancy Registry to investigate the effect of exposure to monoclonal antibodies through breast milk on development during the first three years of life in children born to mothers with MS. The study results will be presented at the American Academy of Neurology's 76th Annual Meeting being held in person in Denver and online on April 13 through 18, 2024.

The researchers identified 180 infants born to mothers with MS and three born to mothers with neuromyelitis optica spectrum disease (NMOSD), a rare demyelinating disease, who used monoclonal antibodies while breastfeeding. The cohort was matched with another 183 infants born to mothers with MS or NMOSD who did not use monoclonal antibodies while breastfeeding. Both groups were followed for a range of 6 months to 3 years, with a median follow-up of 1 year.

In the group exposed to monoclonal antibodies, 125 infants were exposed to Tysabri, 34 to Ocrevus, 11 to Rituxan (rituximab)*, and 10 to Kesimpta. The infants were exposed to MS treatment for an average of five and one-half months, with first exposure ranging from the day of birth to nine months of age.

The researchers compared the following parameters between the group of infants who were exposed to the monoclonal antibodies and those who were not: the children’s weight at follow-up visits during the first three years of life, systemic antibiotic use, number of hospital stays, delays in speech or fine motor skills development, and problems with social development.

Upon comparison, the study results found no significant differences in health or developmental parameters between the two groups.

“Our data show infants exposed to these medications through breastfeeding experienced no negative effects on health or development within the first three years of life,” study author Kerstin Hellwig, M.D. from St. Josef Hospital in Bochum, said in a press release.

*Rituximab is not FDA-approved for MS treatment, but it is often prescribed off-label for this use.