Drug used in infertility support has risks.
TROUBLES IN CANCER THERAPY'S OTHER USE
WASHINGTON - A drug sometimes used to increase a woman's chances of becoming pregnant may cause birth defects and miscarriages, according to a safety alert issued Monday by Canadian health regulators.
The drug letrozole, marketed under the brand name Femara, is approved to treat breast cancer in women who have gone through menopause. But doctors in the United States and Canada often prescribe it ``off-label'' -- using FDA-approved drugs for purposes not approved by the agency -- to prompt ovulation as part of infertility treatments.
Health Canada, the government national health care agency, and Swiss drug maker Novartis have sent letters to Canadian doctors warning them about the unapproved use of the drug.
Although the U.S. Food and Drug Administration is not requiring it, Novartis will send a similar letter to U.S. fertility specialists reminding them that Femara is approved only to treat breast cancer, said Kim Fox, a Novartis spokeswoman. FDA officials were unavailable for comment Monday.
Femara's FDA prescribing information targeted at doctors warns that the drug may harm the fetus when prescribed to pregnant women, citing studies in rats. ``If there is exposure to letrozole during pregnancy, the patient should be apprised of the potential hazard to the fetus and potential risk for the loss of pregnancy,'' the warning states.
Yet the drug, which suppresses the hormone estrogen, is helpful in inducing ovulation and has found favor among some fertility specialists. While the FDA and Health Canada approve drugs as safe and effective for certain treatments, doctors can prescribe drugs any way they see fit.
Fox said Novartis does not know how many women have received the drug as an unapproved infertility treatment. She said Novartis has not promoted Femara or sponsored any studies of it for treatment of infertility.
Numerous Web sites for infertility clinics across the United States, however, discuss Femara as a treatment option.
Novartis has received 13 adverse reaction reports worldwide involving women exposed to Femara during pregnancy.
Of those, four involved harm to the baby, said Jirina Vlk, a Health Canada spokeswoman.
Posted on Tue, Nov. 29, 2005
By Alison Young