FDA Adds Pregnancy Safety Data to MS Treatment Betaseron's Prescribing Information

Mark Rametta, DO

The FDA has approved the inclusion of new safety data on pregnancy in the prescribing information for interferon ß-1b (IFN-ß; Betaseron) in the treatment of relapsing multiple sclerosis, manufacturer Bayer has announced.¹

In addition to observational studies submitted to the FDA, according to Bayer, it also provided data from its global and US pharmacovigilance database of IFN-ß, which included prospective data over several years on the risk of IFN-ß for women who were, or were planning to become, pregnant. Those data showed a similar rate of birth defects and spontaneous abortions in those exposed to IFN-β in comparison with available general population worldwide estimates.

"Young women diagnosed with RRMS often have many questions about whether to continue treatment when they want to start a family or are concerned when an unplanned pregnancy happens while on treatment," said Mark Rametta, DO, FACOI, FACP, the medical director of neurology at Bayer. "We hope information included in the FDA label update will encourage discussion between physicians and their patients and provide answers for doctors to discuss with women who plan to start a family or who have a recently confirmed pregnancy."

The data included came from a 2016 study of 251 pregnancies, which showed that IFN-ß exposure in early pregnancy did not influence mean birth weight, risk of preterm birth, or other adverse pregnancy outcomes. Ultimately, 98.01% of those pregnancies (n = 246) discontinued the treatment during their first trimester.

Birth weight was 3272.28 g (±563.61) for the group of women exposed to disease-modifying therapy compared to 3267.46 g (±609.81) for the matching controls, while mean birth length was 50.73 m (±3.30) for the exposed group and 50.88 cm (±3.45) for the unexposed group. There were no differences between preterm birth (P = .187), spontaneous abortion (P = .304), and congenital anomalies (P = .197) were observed between groups.²

Previously, the FDA’s label for Bayer’s treatment indicated that despite no well-controlled studies in pregnant women, the available data, including prospective observational studies, overall indicated a general, drug-associated risk of major birth defects with IFN-ß during pregnancy. Although, the label also noted that “the majority of the observational studies reporting on pregnancies exposed to [IFN-ß] did not identify an association between the use of IFN-ß during pregnancy and an increased risk of major birth defects.”³

Animal data has indicated, in studied doses ranging from 0.028 to 0.42 mg/kg/day, that when administered in gestation days 20 to 70, a dose-related abortifacient effect was observed. This low- effect dose was approximately 3 times the recommended human dose of 0.25 mg on a body surface area (mg/m²) basis. A no-effect dose for embryo-fetal development toxicity in the rhesus monkeys studied was not established.

According to the FDA, in the United States’ general population, the estimated background risk of major birth defects is between 2% and 4% and of miscarriage is between 15% and 20% in clinically recognized pregnancies. The agency notes in IFN-ß’s label information that background risk of major birth defects and miscarriage for patients with relapsing multiple sclerosis is unknown.

IFN-ß was originally approved for use by the agency in July 1993. In controlled clinical trials, the most common adverse events (AEs) occurring in ≥5% were injection site reaction, lymphopenia, flu-like symptoms, myalgia, leukopenia, neutropenia, increased liver enzymes, headache, hypertonia, pain, rash, insomnia, abdominal pain, and asthenia.

REFERENCES

1. Bayer Updates Betaseron (interferon beta-1b) Prescribing Information in Accordance with the U.S. Food and Drug Administration's Pregnancy and Lactation Labeling Rule [press release]. Whippany, NJ: Bayer; Published December 17, 2018. prnmedia.prnewswire.com/news-releases/bayer-updates-betaseron-interferon-beta-1b-prescribing-information-in-accordance-with-the-us-food-and-drug-administrations-pregnancy-and-lactation-labeling-rule-300764975.html. Accessed December 18, 2018.

2. FDA. Betaseron Prescribing Information Label. Updated August 2018. accessdata.fda.gov/drugsatfda_docs/label/2018/103471s5193lbl.pdf. Accessed December 18, 2018.

3. Thiel S, Langer-Gould A, Rockhoff M. Interferon-beta exposure during first trimester is safe in women with multiple sclerosis-A prospective cohort study from the German Multiple Sclerosis and Pregnancy Registry. Mult Scler. 2016;22(6):801-9. doi: 10.1177/1352458516634872