HOUSTON – Babies born to mothers who took omalizumab just before or during pregnancy exhibited birth defects that are in line with the general population, according to data from the EXPECT registry.
EXPECT (the Xolair Pregnancy Registry) is an ongoing, prospective observational study of pregnant women who received at least 1 dose of omalizumab within 2 months of conception or during their pregnancies.
Dr. Jennifer Namazy of the Scripps Clinic in La Jolla, Calif., presented data from women enrolled between September 2006 and November 2013 at the annual meeting of the American Academy of Allergy, Asthma, and Immunology. The registry aims to enroll 250 women.
Dr. Namazy reported on 186 of the 207 expectant mothers for whom outcomes are recorded. Asthma severity was available for 164. Most (105 or 64%) had severe asthma, while 55 (34%) had moderate asthma, and 4 (2.4%) had mild disease. Each received omalizumab during the first trimester of pregnancy.
A total of 178 births were recorded, 174 of which were live. Of the 170 singletons, 24 (14%) were born at less than 37 weeks’ gestation and of those 3 (13%) were considered small for gestational age (weight less than 10th percentile for gestational age).
Of 140 single-born infants who were carried to full term and also had relevant weight data, 4 (3%) had low birth weight (less than 2.5 kg) and 16 (11%) were considered small for gestational age. Overall, 27 (15%) infants had confirmed congenital anomalies and 11 (6.2%) had a major birth defect.
“This is all very reassuring data,” Dr. Namazy said in an interview. “In terms of the outcomes – major defects and conditional defects – these results are not too unusual, [compared with] the general population. But when we’re looking at infant outcomes, it’s not too different from the severe asthma population.”
She noted, however, that “it’s hard to make large-scale conclusions from this sample size. When you’re talking about congenital malformations, they’re so rare and uncommon that you need a very large population in order to reach any kind of conclusion. But looking at these [data], we’re reassured because there isn’t any consistent information that’s disconcerting; it’s all over the spectrum, and so there’s no significant increase in the rate of birth rate defects that we’re seeing.”
Omalizumab is marketed by Genentech as Xolair. The EXPECT study is funded by Genentech and Novartis Pharma AG. Dr. Namazy is affiliated with Genentech.