USE OF OMALIZUMAB IN PREGNANCY

Omalizumab is a monoclonal humanised IgG1 antibody which binds to IgE and is used in the treatment of moderate-to-severe allergic asthma and chronic spontaneous urticaria (CSU).

The published data specific to omalizumab during pregnancy consist of case reports and small cohort studies collectively describing at least 300 unique omalizumab-exposed pregnancies. While a pharmacovigilance disproportionality analysis includes over 3,000 reports of omalizumab exposure, the study design limits the conclusions that can be drawn, and data from this source do not permit assessment of absolute risks of adverse pregnancy outcomes. Monoclonal antibodies (mAbs) do not actively cross the placenta in the first trimester and are therefore not expected to result in direct fetal exposure; this may lead to a lower risk of teratogenic/embryotoxic effects.

It is important to ensure that maternal asthma is well-controlled in pregnancy. Where asthma is well-controlled with omalizumab, particularly when conventional treatments have been ineffective, the risks and benefits of continuing treatment during pregnancy should be assessed on a case-by-case basis and discussed with the patient as part of a shared decision-making process. Effective control of CSU is also important to protect maternal health and wellbeing, including reducing the risk of poor sleep and associated mental health problems.

Guidance from the UK Health Security Agency (UKHSA) [issued 2017] advises that live vaccines should be avoided until the infant is at least 6 months of age following in utero exposure to biologic immunosuppressant therapies. While omalizumab is not broadly immunosuppressant, the effects of in utero exposure on the neonatal or infant immune system are largely unknown. Please contact UKTIS for an individualised risk assessment where BCG vaccination is indicated in an infant under 6 months of age with prenatal omalizumab exposure.

Exposure to omalizumab at any stage in pregnancy would not usually be regarded as medical grounds for termination of pregnancy or any additional fetal monitoring. However, other risk factors which could independently increase the risk of adverse pregnancy outcome may be present in individual cases. Such factors are important to consider when performing case-specific risk assessments.