Is Xolair (omalizumab) safe to use during pregnancy?

Xolair (Omalizumab) Use During Pregnancy

Xolair (omalizumab) can be used during pregnancy when conventional medications fail to secure asthma control, but should not be considered first-line therapy due to limited safety data. 1

Safety Profile

Omalizumab's safety profile during pregnancy is characterized by:

• Limited data suggest no significantly increased risk of malformations, but the number of exposed women is insufficient to ensure complete safety for the fetus 1
• Case reports of limb reduction defects have been reported 1
• The EXPECT pregnancy registry data shows:
  • Prevalence of major congenital anomalies was 8.1% among singleton infants exposed to omalizumab, similar to 8.9% in a disease-matched comparator cohort 2
  • 99.1% of pregnancies resulted in live births 2
  • Premature birth rate of 15.0% (compared to 11.3% in the comparator group) 2
  • Small for gestational age rate of 9.7% (compared to 15.8% in the comparator group) 2

Mechanism and Placental Transfer

• Monoclonal antibodies like omalizumab cross the placenta, with transport increasing as pregnancy progresses 1
• Potential fetal effects are likely to be greater during the second and third trimesters 1
• Animal reproduction studies have shown no evidence of embryo/fetal adverse effects 1

Treatment Algorithm for Asthma During Pregnancy

1. First-line therapy: Inhaled corticosteroids (particularly budesonide) 3
2. Second-line therapy: Add long-acting beta-agonists if needed
3. Third-line therapy: Consider montelukast for recalcitrant asthma not adequately controlled with inhaled medications 3
4. Fourth-line therapy: Consider omalizumab only when conventional medications fail to secure asthma control 1

Breastfeeding Considerations

• No data available on omalizumab use during breastfeeding 1
• Antibody excretion into breast milk is likely minimal 1
• Gut absorption of antibodies is small except in the first few days of life or in pre-term infants 1

Important Clinical Considerations

• The benefits of controlling maternal asthma generally outweigh the potential risks of medication 3
• Undertreated asthma can result in maternal hypoxia with adverse effects on the fetus 3
• Maintain close monitoring of asthma symptoms and lung function during pregnancy
• Omalizumab should be reserved for cases where conventional therapies are insufficient 1

Potential Risks and Monitoring

• Monitor for signs of allergic reactions after administration
• Schedule regular prenatal visits to assess fetal development
• Consider ultrasound monitoring for fetal growth and development
• Be vigilant for any signs of limb reduction defects or other congenital anomalies

While the observational nature of the EXPECT registry cannot definitively establish an absence of increased risk with omalizumab 2, the current evidence does not show a clear pattern of increased adverse pregnancy outcomes compared to women with similar disease severity not treated with the medication.