Comparable Pregnancy and Infant Milestones With Infliximab Biosimilars vs Originator in IBD

A study evaluating pregnancy outcomes and infant developmental milestones found similar outcomes between pregnant women with inflammatory bowel disease (IBD) who received reference infliximab and those who received a biosimilar. There were no significant differences between groups for pre-term birth, small for gestational age, and low birth weight, and infant developmental milestones up to 12 months.

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The authors said it is important to understand how to manage IBD during pregnancy because the peak reproductive years are also the peak years for diagnosis of IBD, which includes Crohn disease (CD) and ulcerative colitis (UC). They cited large prospective studies demonstrating the safety of anti-tumor necrosis factor (TNF)-α biologics such as infliximab for IBD treatment during pregnancy, but noted that these were primarily conducted with originators, not biosimilars. They added that for many years after biosimilars became available, insurance plans in the US offered an exception allowing the use of originators during pregnancy due to limited data on biosimilars and pregnancy outcomes.

Although infliximab crosses the placenta during the second and third trimesters and can be detected in infants for up to 9 months after birth, the authors said no increase in infections, differences in vaccine response, or other complications have been reported in infants.

The study compared pregnancy and neonatal outcomes as well as developmental milestones for children at 1 year in 100 women with IBD receiving the infliximab originator and 20 women receiving a biosimilar between 2017 and 2024.

Approximately two-thirds of the participants had CD. Of those treated with biosimilars, 13 (65%) received infliximab-dyyb (CT-P13) and 7 (35%) received infliximab-axxq. Characteristics of the two groups were “generally similar,” however the biosimilars group had a significantly longer median disease duration compared to the reference product group (17 vs 10 years; IQR, 7-21 vs 6-15).

Of the women on biosimilars, 63% continued therapy through delivery compared to 87% of those on the originator. None of the women on the biosimilar and 5 (5%) on the originator had active disease during pregnancy.

Adverse pregnancy outcomes other than caesarean section were “generally rare” and incidence was similar in both groups, including spontaneous abortion (2% and 0% in originator and biosimilar groups), preterm birth (5% and 5%), intrauterine growth restriction (2% and 5%), small for gestational age (5% and 4%), and low birth weight (9% and 5%).

Thirty-five percent of women in the originator and 25% in the biosimilar group had caesarean sections. There was no difference in the incidence of any pregnancy complication other than caesarean section between groups (48% vs 35%; P = .29). Infant milestones, such as communication, fine and gross motor skills, personal social skills, and problem solving at one year were also not significantly different between groups.

According to the authors, as of yet there have only been small, retrospective studies without a comparator group of biosimilar use during pregnancy, and their study is the largest to date of pregnant women with IBD on biosimilar infliximab products. Infliximab biosimilar use was not associated with any adverse pregnancy or infant outcomes. The authors said their results can help inform shared decision making for patients with IBD who are contemplating pregnancy.

Reference

Long MD, Kane S, Beaulieu D, Abraham B, Zhang X, Mahadevan U. Use of biosimilars to infliximab during pregnancy in women with inflammatory bowel disease: results from the Pregnancy in Inflammatory Bowel Disease and Neonatal Outcomes Study. Clin Transl Gastroenterol. 2024;15(12):e00795. doi:10.14309/ctg.0000000000000795