Health Canada Warns of Birth-Defect and Miscarriage Potential for Transplant Anti-rejection Drugs

Canada’s health regulatory agency has issued a warning that CellCept (mycophenolate mofetil) and Myfortic (mycophenolate sodium), drugs given to prevent organ rejection in transplant patients, can cause miscarriage and congenital malformations if taken during pregnancy.

The agency warns against using CellCept and Myfortic during pregnancy because of their potential to change the DNA (mutagenicity) or interfere with the normal development of the fetus (teratogenicity). The drugs should not be taken by a woman who could become pregnant unless she is using highly effective contraceptive methods. Further, because of the drugs’ potential to alter DNA, women who are breastfeeding should not take them.

Congenital malformations—sometimes multiple—have been reported in children of patients who took mycophenolate mofetil in combination with other immunosuppressants during pregnancy.

The most frequently reported malformations are:

  • facial malformations such as cleft lip, cleft palate, undersized jaw, increased distance between the eyes;
  • abnormalities of the ears and eyes;
  • malformations of the fingers;
  • cardiac abnormalities such as atrial and ventricular septal defects;
  • esophageal malformations;
  • nervous system malformations (such as spina bifida).

CellCept is given to prevent organ rejection in adult patients who have received kidney, heart, or liver transplants. CellCept is also prescribed for pediatric patients (2 to 18 years of age) who have received kidney transplants. Myfortic is prescribed for kidney transplant patients. These drugs are administered in combination with cyclosporine and corticosteroids.

Health Canada says physicians should ensure that women and men taking mycophenolate drugs understand the risk of harm to the baby, the need to use effective birth control, and the need to immediately consult a physician if there is a possibility a woman might be pregnant.

Health Canada made these recommendations based on a cumulative review of birth defects that confirmed that mycophenolate is a human teratogen (i.e., causes birth defects). The evidence showed an increased rate of congenital malformations and miscarriages associated with mycophenolate in comparison with other immunosuppressant drugs.

According to Health Canada, evidence from the medical literature indicates that malformations occurred in 23 to 27 percent of live births in women exposed to mycophenolate mofetil during pregnancy, compared to 2 to 3 percent of live births in the overall population and approximately 4 to 5 percent in organ transplant patients treated with immunosuppressants other than mycophenolate mofetil. Spontaneous abortion (miscarriage) has been reported in 45 to 49 percent of patients exposed to mycophenolate mofetil during pregnancy, compared to a reported rate between 12 and 33 percent in organ transplant patients treated with other immunosuppressants.

Health Canada says that women and men taking either CellCept or Myfortic should receive information about the risk of harm to the baby, the need for effective contraception, and the need to consult a doctor immediately if there is the possibility of pregnancy. Women who could become pregnant should be aware of the increased risk of pregnancy loss and congenital malformations and must be counseled about pregnancy prevention and planning.

The health agency advises women who could become pregnant to use two reliable forms of contraception simultaneously before they begin taking mycophenolate, during mycophenolate therapy, and for six weeks following discontinuation of therapy, unless abstinence is their method of contraception.


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