VIENNA — Dupilumab (Dupixent) was not associated with an increased risk for major structural birth defects or other adverse pregnancy and infant outcomes in a prospective registry involving women treated for atopic dermatitis or asthma.

Notably, the association held regardless of the comparison group being used: pregnant women with atopic dermatitis who had not taken dupilumab; pregnant women with asthma, with or without atopic dermatitis, who had or had not taken dupilumab; and healthy pregnant women who had neither disease.

“The main take-home is that the data are generally very reassuring,” Christina Chambers, PhD, MPH, University of California, San Diego (UCSD), told Medscape News Europe.

Chambers, who presented the final findings from the Dupilumab Pregnancy Exposure Registry here at the European Academy of Dermatology and Venereology (EADV) 2026 Congress, added they were important because drug studies are rarely done in pregnant women, or pregnant women are actively excluded. 

“We have drugs on the market that might be the very best drug for a woman to take, but if she’s pregnant, she and her clinician have a difficult decision to make because they just don’t have any data,” Chambers added.

Dupilumab Pregnancy Exposure Registry

An estimated 10%-12% of women of reproductive age have atopic dermatitis or asthma, and some may require advanced treatment for moderate-to-severe disease during pregnancy, Chambers said during her presentation.

Although dupilumab “might be one of those treatments,” there are limited published data on the safety of its use during pregnancy, which is why Chambers and her team set up the Dupilumab Pregnancy Exposure Registry in 2018.

Run as part of the MotherToBaby Pregnancy Studies program at UCSD and registered with ClinicalTrials.gov, the aim of the registry is to evaluate the effect of dupilumab exposure on pregnancy rates and infant outcomes in exposed pregnancies compared with unexposed disease-matched pregnancies and healthy unexposed pregnancies.

Between October 2018 and January 2024, 539 pregnancies were included in the registry. Dupilumab was used during 238 pregnancies in women with active disease (95 with atopic dermatitis and 143 with asthma, with or without atopic dermatitis). Of the remaining pregnancies, 175 were in women with active disease who had not received dupilumab (33 with atopic dermatitis and 142 with asthma, with or without atopic dermatitis), and 126 were in a healthy comparison group.

Chambers said that women had been recruited into the registry while pregnant and that data such as dupilumab use were collected prospectively. This was done via medical records and maternal interviews during pregnancy at set timepoints and up to 1 year postpartum, with a few specialized physical examinations undertaken of liveborn infants. 

Dupilumab Use and Pregnancy Outcomes

Across all the dupilumab-treated pregnancies, 197 (82.8%) resulted in a live birth. Similar results were seen in the unexposed groups, with 141 (80.6%) live births occurring in the active comparator group and 102 (81.0%) in the healthy comparison group. Conversely, stillbirth rates were very low at 0.8%, 0.6%, and 1.6%, respectively.

Spontaneous abortion occurred in nine of 160 (5.6%) dupilumab-exposed pregnancies, three of 91 (3.3%) unexposed active-disease pregnancies, and four of 113 (3.5%) unexposed healthy pregnancies.

The primary outcome was major structural birth defects among liveborn infants. The proportion of liveborn infants with major structural birth defects was 7.6% (14/185) in the dupilumab-exposed group and 9.2% (13/141) in the disease-matched unexposed group. After adjustment for potential confounders, risk ratios ranged from 0.61 to 0.77, but the differences were not statistically significant.

“Pretty similar results were found in comparison to the healthy comparison group,” she added. Compared with the healthy unexposed group, the adjusted risk ratio for major structural birth defects was 1.17 (95% CI, 0.51-2.69), also indicating no statistically significant difference.

There was also no pattern of minor malformations associated with dupilumab. “So no evidence of human teratogenicity in this study,” Chambers said.

As for other neonatal adverse outcomes, there was no statistically significant evidence of an increased risk with dupilumab treatment in comparison to the disease-matched group. Outcomes included preterm delivery, birth weight, and postnatal weight; serious and opportunistic infections; and hospitalizations up to 1 year of age.

Compared with the healthy pregnancy group, dupilumab exposure was associated with an approximately threefold higher estimated risk for birth weight below the 10th percentile. Chambers suggested this might reflect the underlying maternal disease rather than the treatment itself.

She concluded that the findings were consistent with the “limited existing published literature, and we think provide at least some reassuring data to patients and providers who wish to use this drug for appropriate treatment in pregnancy.”

These data were observational, and “no single study is going to be the answer to everything,” Chambers acknowledged. “We’ll need more data from other types of study designs.” One limitation of the study was the relatively small number of dupilumab-exposed pregnancies (n = 238), particularly among women treated for atopic dermatitis alone (n = 95), which limits the certainty of the findings.

‘Encouraging’ Data on Dupilumab Safety in Pregnancy

Robert Smith, MD, assistant professor of dermatology at the Johns Hopkins University School of Medicine in Baltimore, called the data “really encouraging” when interviewed by Medscape News Europe after the meeting.

“Whenever we’re talking about a drug in pregnancy, we always like to remind people that there’s a background rate of birth defects and birth anomalies that happen in the general population, and so there’s always this concern that a medication given during pregnancy could induce or increase them,” Smith said.

“That’s why it’s so important to have the dupilumab – exposed group compared to the dupilumab – unexposed group and the healthy controls, and to see that the rates of major birth defects look not significantly different across the board is just very encouraging.”

Almost 70% of the women exposed to dupilumab had taken the drug from the first trimester and throughout their entire pregnancy, which “bolsters the results,” said Smith.

There was another side to it all, however. “A lot of times people are thinking, ‘Is this safe for the baby?’ But we also have to think about, ‘Well, is it safe for mom to not be on this medication?’”

Smith explained that increased itch, lack of sleep, and increased use of topical steroids that could result from not using a biologic “could have a secondary impact. We don’t know what the impact of that has on the developing fetus.”

The study was funded by Regeneron Pharmaceuticals and Sanofi Aventis. Chambers reported receiving research funding from Amgen, Bristol Myers Squibb, Glaxo Smith Kline, Janssen, Leo, Novartis, Pfizer, Sun, Takeda, and UCB. Smith reported having no relevant financial relationships.

Sara Freeman, MSc, is a freelance medical journalist based in London, UK. She has been reporting for specialist healthcare news organizations for more than 20 years.