FDA Drops Pregnancy Contraindications for Interferon Beta Products

April 4, 2020

Both the Plegridy and Avonex drug labels no longer contain the "Pregnancy Category C" classification with the report of human pregnancy registry data.

US FDA

The FDA has approved updated prescribing information for both interferon beta-1a (Avonex; Biogen) and peginterferon beta-1a (Plegridy; Biogen), including the removal of contraindications for pregnancy.

The decision follows a similar judgement in Europe that was approved last year.

“Many women with MS are diagnosed during their childbearing years. With this important update for PLEGRIDY and AVONEX, healthcare providers have more data to inform appropriate treatment paths for patients who may be pregnant or planning for pregnancy,” said Bernd Kieseier, MD, MHBA, Executive Director, Head of Global MS, Worldwide Medical at Biogen, in a statement.

The drugs, which are approved for the treatment of relapsing forms of multiple sclerosis, including clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease, were shown to not have a deleterious effect on pregnancy outcomes. The decision was made based on data from more than 1000 real-world pregnancies that showed there was no association between treatment with the drugs during early pregnancy and risk for major congenital anomalies.

Specifically, the drug labels no longer contain the “Pregnancy Category C” classification. Data from observational studies in humans show no association between use of interferon beta products during early pregnancy with an increased risk for major birth defects. Specifically, a population cohort study conducted in Finland and Sweden on 2831 pregnancy outcomes in women with MS showed no increased risk of birth defects in women exposed to interferon beta products compared to those who were unexposed to any non-steroid MS therapy. While there were no increased risks observed for miscarriages or ectopic pregnancies, it was difficult to obtain complete data on these outcomes and therefore cautious interpretation of those findings is encouraged.

Notably, data from 2 smaller cohort studies suggest that exposure to interferon beta products during pregnancy may be associated with a decrease in mean birth weight, however those findings have not been confirmed in larger observational studies. In addition, findings from other small studies suggest an increased prevalence of miscarriage and preterm birth; however, neither of those outcomes have been confirmed in larger studies.

In animal studies, subcutaneous injection of interferon beta products during early pregnancy in monkeys was not associated with any adverse effects on embryo-fetal development, however an increase in abortion activity was observed following 3 to 5 doses of interferon beta at 100 times the recommended weekly human dose.