Biogen’s Plegridy or Avonex Use Possible in Pregnancy, Breastfeeding, FDA Says

Plegridy (peginterferon beta-1a) and Avonex (interferon beta-1a), both by Biogen, may be used — if necessary — by women with relapsing multiple sclerosis who are pregnant or breastfeeding, the U.S. Food and Drug Administration (FDA) announced in updating prescribing information for these MS treatments.

Due to the limited nature of data supporting their use under these circumstances, however, patients should continue to notify their healthcare provider if they are pregnant or planning a pregnancy.

“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,” Bernd Kieseier, MD, Biogen’s executive director, head of global MS and worldwide medical, said in an email reply to Multiple Sclerosis News Today.

The FDA’s decision follows a similar ruling by the European Medicines Agency for interferon beta (IFN-beta) therapies, which also include Rebif (interferon beta-1a) by Merck KGaA. That ruling, announced last year, followed the favorable opinion of its Committee for Medicinal Products for Human Use (CHMP). (Merck KGaA is known as EMD Serono in North America.)

Both decisions were based on data from the European Interferon Beta Pregnancy Registry, and the national health registers of Finland and Sweden. These studies included more than 1,800 real-world pregnancies in women with MS who used IFN-beta in the three months immediately before conception, or during their pregnancy.

A comparison between outcomes for these women and MS patients who went without treatment before or during a pregnancy showed no association between IFN-beta-based therapy use during the first trimester of pregnancy and an increased risk of major birth defects.

A recent Nordic study also found no link between IFN-beta exposure and fetal growth or gestational age among infants of MS patients.

“The majority of observational studies reporting on pregnancies exposed to interferon beta products did not identify an association between the use of interferon beta products during early pregnancy and an increased risk of major birth defects,” the FDA label for both Avonex and Plegridy now states in section 8.

But data on IFN-beta exposure duration the first trimester — and particularly in later stages of pregnancy — remains limited. During the studies cited, stopping IFN-beta treatment was still recommended during pregnancy.

Therefore data so far do not allow reliable conclusions to be drawn on the risk of spontaneous abortions in women with MS treated with IFN-beta. Available evidence, however, suggests no increased risk.

Similarly, limited data suggest that the levels of IFN-beta excreted in human milk are negligible, and that these treatments pose no health risk to the breastfed newborn or infant.

As a result of FDA’s decision, the updated label for Avonex and Plegridy no longer has the “pregnancy category C” classification. This classification indicated that animal studies showed adverse effects on fetuses, and that well-controlled studies in patients were lacking. But the therapy’s potential benefits could warrant its use, despite its potential risks.

The labels for Plegridy and Avonex now provide human and animal studies data on the use of IFN-beta therapies during pregnancy and breastfeeding, so that more informed decisions can be made when analyzing the benefits and potential risks of these therapies.

Women with MS, however, are strongly urged to continue to notify their healthcare provider if they are pregnant or plan on becoming pregnant.

Further studies and the information being recorded in registry databases may help to clarify these potential risks, aiding expecting parents and their medical team in making treatment decisions.