Health regulators warned again Friday that Roche and Novartis drugs prescribed to organ transplant patients can cause miscarriages and birth defects when used by pregnant women.
The Food and Drug Administration last October said it received reports of miscarriages and infants born with ear and mouth birth defects after their mothers took Roche's CellCept. At the time, FDA added its most serious warning to CellCept and a similar Novartis AG drug, Myfortic.
FDA spokesman Christopher Kelly said the agency has not received any new reports of pregnancy-related problems, but was concerned some doctors may not have seen the initial warning.
CellCept and Myfortic are used to suppress the body's immune system to avoid organ rejection in transplant patients.
In a notice posted online Friday, FDA said that before prescribing the drugs doctors should confirm their transplant patients are not pregnant, and are using effective contraception.
FDA said most of the reported problems came from mothers who were taking CellCept before their pregnancies were detected. Some of the patients were taking the drug for conditions it was not approved to treat — including rheumatoid arthritis and lupus.
A spokesman for Roche said it has not received any new reports of miscarriages or birth defects since updating the drug's labeling. The company previously reported 25 miscarriages among 77 women exposed to the drug between 1995 and 2007.
The agency said it will continue working with Roche and Novartis to reduce use of the drugs by pregnant women.
Friday's FDA warning was the second in less than two months for Roche's CellCept, which was the Swiss drugmaker's sixth best-selling drug last year with revenue of nearly $2 billion.
Last month FDA said it was investigating 16 patients who developed a rare neurological disease while taking the drug.
The disease, known as progressive multifocal leukoencephalopathy, attacks the brain and central nervous system and is usually fatal. Symptoms include vision problems, loss of coordination and memory loss. Patients who survive are often permanently disabled, according to the FDA.
Shares of Novartis AG rose 8 cents Friday to $51.27.