These two studies firm up our knowledge regarding anti-TNF therapy during pregnancy. They confirm that the IgG1 monoclonal antibodies infliximab and adalimumab have substantial transplacental transfer that increases during the third trimester. Infants born to women who continue these medications during the third trimester will have detectable drug concentrations that persist for 2-7 months.
No serious infectious events occurred in these studies. However, there is a previous report of an infant whose mother took infliximab during the third trimester who was vaccinated with the live organism BCG [Bacille Calmette Guerin] and developed disseminated BCG, which ultimately led to death (J. Am. Acad. Dermatol. 2011;65:870). This case report demonstrates that infants who are born with detectable infliximab or adalimumab levels are at risk for opportunistic infections. In contrast, certolizumab pegol does not cross the placenta.
The studies also show that interruption of infliximab or adalimumab at the end of the second trimester substantially reduces the amount of antibody transferred to the infant and shortens the time required for the infant to clear the antibody. Finally, discontinuation of infliximab and adalimumab during the third trimester appears to be associated with a low risk of relapse.
Altogether, these findings would appear to support the discontinuation of infliximab and adalimumab during the third trimester. Discontinuation of certolizumab pegol is not necessary.
William J. Sandborn, M.D., AGAF, is chief of the division of gastroenterology and director of the UCSD IBD Center in the University of California San Diego Health System. He has consulted for and received research grants from Janssen and consulted for AbbVie (previously Abbott Laboratories) and UCB Pharma.
