Researchers in the University of Florida College of Pharmacy have determined that mycophenolate, a common drug used to weaken the immune system, is approximately two times more likely to cause miscarriage among women exposed to the drug during their pregnancy. They compared the risk to azathioprine, which is considered a safer alternative for women of child-bearing age depending on their medical condition.
Mycophenolate was approved by the U.S. Food and Drug Administration in 1995, and became the mainstay of the post-transplantation regimen. Currently, it is prescribed for several other indications that are caused by over activation of the immune system, including systemic lupus (an inflammatory disease of skin and internal organs), psoriasis (an inflammatory condition of skin and joints) and autoimmune hepatitis (an inflammatory disease of liver).
The risk of miscarriage and birth defects was discovered in the early 2000s by several medical case reports, and the FDA took action in 2008 to update the label with a strong warning against maternal exposure. In 2012, the FDA required drug sponsors to start a risk management plan called REMS to inform the doctors and patients about the risk. The program involves training and requirements to perform routine pregnancy testing and contraception use during treatment.
To date, no studies had quantified the amount of increased risk of miscarriage compared to a safer treatment option. Although the net number of exposed pregnancies does not appear to be high in the U.S., the outcome of a miscarriage or infant malformations could be devastating. Our study findings support the rationale for the REMS program to inform patients and health care providers about the significant risk and the requirement for pregnancy check and full adherence to reliable contraception methods, if the treatment could not be avoided due to potential medical benefits.
The lead authors, Thuy Thai and Amir Sarayani, conducted the study under supervision of Almut Winterstein, Ph.D., R.Ph., who serve as a professor and the Dr. Robert and Barbara Crisafi Chair of Pharmaceutical Outcomes and Policy in the UF College of Pharmacy. A previous study by the same team has investigated the effectiveness of the REMS program for mycophenolate.
The peer-reviewed paper titled, “Risk of pregnancy loss in patients exposed to mycophenolate compared to azathioprine: A retrospective cohort study,” was originally published in the journal of Pharmacoepidemiology and Drug Safety.