Femara appears safe as fertility agent

NEW YORK (Reuters Health) - Findings from a new study should help reassure doctors and their female patients that Femara (letrozole), an inexpensive, easy-to-use fertility agent, is just as safe as clomiphene citrate, a drug that has been used for more than 40 years.

These drugs increase fertility in women who have difficulty producing eggs or "ovulating." They are typically given for several days during each cycle, and most women do ovulate when they take the drugs.

Despite being the first-line therapy for ovulation problems, clomiphene citrate is associated with rather low pregnancy rates. So drugs called aromatase inhibitors, especially Femara, have been tried to stimulate ovulation, the authors explain. Reports have suggested that pregnancy rates are, in fact, slightly higher with aromatase inhibitors than with clomiphene citrate.

However, the findings of a small study presented at a reproductive medicine meeting in 2005 suggested a link between Femara use and birth defects in the newborn. This led the manufacturer, Novartis Pharmaceuticals, to issue a statement advising against the use of Femara in premenopausal women.

In the present study, reported in the journal Fertility and Sterility, Dr. Robert F. Casper and colleagues reexamined this concern by analyzing data from 911 infants born to women who had used Femara or clomiphene citrate for ovulation induction.

The rate of birth defects was not significantly different between the groups and was actually slightly higher among infants of clomiphene citrate users than Femara users: 4.8 versus 2.4 percent. The corresponding rates of major defects were 3.0 and 1.2 percent.

As for heart defects, a concern that was raised in the 2005 study, clomiphene citrate was associated with a significantly higher rate of these abnormalities than was Femara: 1.8 versus 0.2 percent.

"The concern that Femara use for ovulation induction could be (harmful to the baby) is unfounded based on our data," the authors conclude.

SOURCE: Fertility and Sterility, June 2006.