ROCKLAND, Mass., May 27, 2020 /PRNewswire/ -- EMD Serono, the biopharmaceutical business of Merck KGaA, Darmstadt, Germany, in the U.S. and Canada, announced today the U.S. Food and Drug Administration (FDA) has approved the inclusion of new safety data on pregnancy and breastfeeding in the prescribing information for Rebif® (interferon beta-1a), in accordance with the FDA's Pregnancy and Lactation Labeling Rule (PLLR). With a safety profile supported by 20+ years of combined clinical trial data and real-world patient experience, Rebif is indicated for the treatment of relapsing forms of multiple sclerosis (MS), to include clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease, in adults.3     

Consistent with the new PLLR requirements, the label for Rebif will no longer have the pregnancy category C designation and contains additional data to assist healthcare providers in assessing benefit versus risk and support counseling of pregnant women and nursing mothers. Patients should continue to notify their healthcare provider if they are pregnant or plan to become pregnant.

"At EMD Serono, we are dedicated to supporting women with MS at every stage of their life journey, including when planning to start or expand their families," said Maria Rivas, MD, Global Chief Medical Officer, SVP, EMD Serono. "Today's update provides physicians critical information to help inform women with MS in managing this chronic disease during a very important time in their lives." 

MS is a chronic disease affecting twice as many women as men and is often diagnosed between the ages of 20-40 years.1 Pregnancy is a key treatment consideration as more than 50 percent of female patients with relapsing MS are of childbearing age and an estimated one-third have discussed planning a pregnancy in the next three years with their healthcare provider.2

"Women with MS often have concerns and questions for their doctors about continuing disease modifying treatments as they are trying to conceive, or if they do become pregnant," said Maria Houtchens, MD, Associate Professor of Neurology, Brigham and Women's Hospital, Boston. "The inclusion of pregnancy outcomes and lactation data in the Rebif label provides valuable insights. I believe it will encourage discussions between physicians and their patients about MS treatment options when considering pregnancy."

The update was based on data from a Nordic register-based study of 2,831 women, as well as a European registry and other published studies over several decades, which have not identified a drug-associated risk of major birth defects with the use of interferon beta products during early pregnancy. Findings regarding a potential risk for low birth weight or miscarriage with the use of interferon beta products in pregnancy have been inconsistent.3

Previously, human data on breastfeeding during interferon beta treatment was not available. Now, new, albeit limited, data shows the presence of interferon beta-1a products in human milk at low levels, giving healthcare providers and their patients more information to assist with their decision making. There are no data on the effects of interferon beta-1a on milk production. Therefore, the developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for Rebif and any potential adverse effects on the breastfed child from Rebif or from the underlying maternal condition.3

For more information on Rebif, including prescribing information, visit

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