Tysabri safe as treatment for MS during pregnancy, breastfeeding
Study suggests treatment doesn't harm mother or baby
Tysabri (natalizumab), an approved treatment for forms of multiple sclerosis (MS), can be safely used during pregnancy or while breastfeeding, a study showed.
“The findings of our observational study offer … relevant insight into the safety profile of [Tysabri] therapy not only during pregnancy but also during breastfeeding,” the researchers wrote, adding that their data “confirms the safety of [Tysabri] treatment for both mother and child.”
The study, “Long-term safety evaluation of natalizumab during pregnancy and lactation in patients with multiple sclerosis,” was published in Neurological Sciences.
MS predominantly affects women, and it often manifests in early adulthood. While many people with MS are interested in becoming pregnant and breastfeeding their babies, few treatments for MS have been rigorously studied in people who are pregnant or breastfeeding. The infusion therapy Tysabri, also available as the biosimilar Tyruko, is one for which there are minimal data relating to pregnancy or breastfeeding.
The therapy, widely approved to treat relapsing types of MS, works by preventing inflammatory immune cells from getting into the brain and spinal cord, thereby limiting disease-driving inflammation.
Study from Italy looks at 14 women
A trio of scientists in Italy reported on outcomes for 14 women who were treated with Tysabri during pregnancy. Ten of the patients continued on Tysabri while breastfeeding their babies; the others chose not to breastfeed. For all of the women, Tysabri was continued until midway through the third trimester, then paused a few weeks before birth and restarted a few weeks after birth.
None of the women experienced MS relapses during pregnancy, and markers of disease activity were generally stable throughout pregnancy and the postpartum period. One woman experienced a momentary worsening of MS symptoms after giving birth without signs of new disease activity on MRI scans, and two women had increases in numbers of MS lesions on MRI scans after giving birth but without worsening symptoms.
The data suggest “favorable disease control in the postpartum period after early resumption of treatment with [Tysabri],” the researchers said.
A total of 15 babies, including one set of siblings, were born to the 14 mothers. All of the babies showed normal signs of development, and no notable issues with the health of any of the children were reported.
“The absence of prematurity and normal birth weight and head circumference measurements confirm favorable neonatal outcomes after [Tysabri] exposure during pregnancy; the lack of developmental delays in children support the safety of [Tysabri] exposure during pregnancy in the long term,” the researchers wrote.
The study suggests that Tysabri can be safely used during pregnancy and while breastfeeding, the researchers said, though they noted that their study was limited by its small size.
“Continued vigilance and long-term follow-up are imperative to comprehensively evaluate the developmental trajectory and long-term health outcomes of children born to mothers receiving [Tysabri] during pregnancy and breastfeeding,” the scientists said.
Tysabri is marketed by Biogen, which was not involved in the study. The research was supported by project MNESYS, a European effort aiming to improve understanding of the nervous system in health and disease.
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