Omalizumab and Treatment of Severe Refractory Asthma in Pregnant Women
Omalizumab is commonly recommended for the treatment of severe refractory asthma. A special group of patients are pregnant women with asthma, for whom the risks of inadequately treated asthma must be weighed against the risks of biological treatment for the fetus. EXPECT is a pregnancy registry that has served since 2006 as a prospective observational study; its aim is to collect data on women treated with omalizumab during pregnancy and compare it with data from asthmatic women who did not receive omalizumab.
Omalizumab and asthma treatment during pregnancy
The incidence of asthma is currently rising, and at the same time, the number of women of childbearing age diagnosed with asthma is increasing. The question of adequate asthma treatment during pregnancy is thus receiving increasing attention. On one hand, there is the negative impact of uncontrolled asthma during pregnancy on the fetus. The fetus is at risk from maternal hypoxia, impaired placental perfusion, and the action of inflammatory mediators due to insufficiently controlled asthma. All these factors can lead to developmental disruptions and perinatal complications. On the other hand, there are the safety and risks of anti-asthmatic treatment. Information on the safety of a specific drug during pregnancy is obtained from animal studies, case reports, case-control studies, and data from prospective cohorts.
Omalizumab is a humanized monoclonal antibody against immunoglobulin E (IgE), which plays a significant role in the pathogenesis of asthma. It has been registered in the Czech Republic since 2005. Omalizumab therapy is recommended for patients with severe persistent allergic asthma who, despite adequate treatment with high doses of inhaled corticosteroids (ICS) and long-acting beta2-agonists (LABA), suffer from frequent exacerbations, reduced lung function, and frequent symptoms during the day or night.
Omalizumab crosses the placenta and also into breast milk. Genotoxic studies in animals do not indicate direct or indirect harmful effects.
EXPECT Study
EXPECT is a pregnancy registry that since 2006 has served as a prospective observational study of women treated with omalizumab during pregnancy. The aim is to collect and evaluate the perinatal outcomes of women who received omalizumab during pregnancy. Given that severe asthma per se can affect perinatal outcomes, the data from the registry were compared with data from a comparative cohort. This cohort consisted of pregnant women with severe or moderate asthma who were not treated with omalizumab during pregnancy.
Results
A total of 250 women were enrolled in the EXPECT study, with data collected up to 18 months postpartum. The comparative cohort included 1153 women. The prevalence of major congenital anomalies was comparable between the EXPECT study group and the control group (8.1% vs. 8.9%). The incidence of stillbirths or fetal deaths (0.9% vs. 0.9%) and preterm births (15.0% vs. 11.3%) were also similar.
Conclusion
No association was observed between omalizumab therapy during pregnancy and an increased incidence of major congenital anomalies or thrombocytopenia in the children of treated women. Perinatal outcomes for women with asthma treated with omalizumab and for those with moderate to severe asthma who did not use omalizumab during pregnancy were comparable. Given the observational nature of the EXPECT registry, a detrimental effect of omalizumab on the fetus cannot be entirely ruled out. Currently, the administration of omalizumab to pregnant women may be considered when clinically indicated.
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Sources:
1. Heribanová L. Perinatal outcomes of pregnant women with asthma treated with omalizumab compared to a cohort of pregnant women with moderate and severe asthma without omalizumab – EXPECT registry: Commentary on the study. Farmakoterapie 2019; 15(4): 557−559.
2. SPC Xolair. Available at: www.ema.europa.eu/en/documents/product-information/xolair-epar-product-information_en.pdf
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