Is Infliximab (chimeric monoclonal antibody) safe to use during pregnancy?

Infliximab Use During Pregnancy

Infliximab should be continued during the first and second trimesters of pregnancy to maintain disease remission, but should be discontinued after 30 weeks of gestation when possible due to placental transfer and potential risks to the infant. 1

Safety Profile During Pregnancy

• Infliximab crosses the placenta primarily during the late second and third trimesters 2
• FDA labeling indicates no clear association with adverse pregnancy outcomes 3
• The drug can be detected in infant serum for several months after birth due to active placental transfer 3, 2
• Available evidence from registry studies involving more than 300 pregnancy outcomes suggests infliximab carries low fetal risk 2

Management Algorithm for Infliximab During Pregnancy

1. Pre-conception and First Trimester:

   • Continue infliximab therapy to maintain disease remission 1
   • Ensure adequate folic acid supplementation (2 mg/day) if combined with sulfasalazine 1

2. Second Trimester:

   • Continue infliximab therapy to maintain disease remission 1
   • Monitor disease activity closely

3. Third Trimester:

   • If disease is well-controlled: Discontinue infliximab after 30 weeks of gestation 1, 2
   • If active disease is present: Consider continuing therapy, weighing maternal benefits against potential fetal risks 1

4. Postpartum Considerations:

   • Infants exposed to infliximab in utero should not receive live vaccines for at least 6 months after birth 3, 4
   • Monitor infants for potential hematologic abnormalities (60% may have anemia) 1

Special Considerations and Cautions

• A fatal case of disseminated BCG infection has been reported in an infant who received the BCG vaccine at 3 months after in-utero exposure to infliximab 4
• The British Association of Dermatologists recommends avoiding infliximab infusions after 30 weeks if possible due to its relatively long half-life (8-9 days) and evidence of placental transfer 1
• The Toronto Consensus Statement recommends continuation of anti-TNF therapy throughout pregnancy to maintain remission 1

Breastfeeding Considerations

• Limited evidence indicates that infliximab is not excreted in significant amounts in breast milk 1, 5
• The FDA states that available information is insufficient to determine the amount of infliximab in human milk 3
• The benefits of breastfeeding should be weighed against potential risks, though case reports suggest minimal risk 6, 5

Key Pitfalls to Avoid

1. Stopping therapy prematurely: Discontinuing infliximab early in pregnancy may lead to disease flares, which can negatively impact pregnancy outcomes
2. Administering live vaccines to exposed infants: Postpone live virus vaccines until infliximab is undetectable in infant serum (may take >6 months) 3, 2, 4
3. Failing to monitor for infant anemia: Consider complete blood count testing for exposed newborns 1

Remember that maintaining disease remission during pregnancy is crucial for both maternal and fetal outcomes, and the risks of active disease may outweigh the potential risks of continuing infliximab therapy.