Yaz ingredient not properly tested, FDA warns Bayer

The U.S. Food and Drug Administration has admonished German drug manufacturer Bayer for failing to test a vital ingredient used in Yaz and other birth control drugs according to American standards.

The “deviations,” as the FDA called them, were cited in a letter dated September 9th and sent to Dr. Franz-Josef Renneke, the Site Manager of Bayer’s plant in Bergkamen, Germany. The FDA published the letter on its website this week.

The FDA found that Bayer tested the quality of some drug ingredients, including drospirenone, a main ingredient in Yaz, using a method the U.S. does not accept. The method involves averaging a group of several samples, rather than providing test results for each ingredient batch. The U.S. requires foreign pharmaceutical manufacturers to conform to American standards when testing the quality of its U.S.-bound exports.

Earlier this year, the FDA warned Bayer that it exported ingredients to the U.S. between 2007 and 2009 yet failed to test them using U.S.-approved methods. Bayer responded in April that it had analyzed all relevant batches and concluded that their quality “was not affected.”

That’s beside the point, the FDA’s letter last week said.

“Your firm concluded that these … results were within the accepted variation of the analytical method and that the quality of these batches was not affected,” the FDA letter stated. “We disagree with your rationale and conclusion. An assay test is used to determine potency, not method variability.”

Yaz and Yasmin were Bayer HealthCare’s best-selling drugs last year, with sales reaching $1.8 billion worldwide.

The FDA has not discovered quality problems in the German imports and does not advise consumers taking Yaz to stop. The FDA’s warning is meant to prevent quality problems from occurring in the future.

According to the Associated Press, “The FDA regularly issues warning letters to companies that do not follow regulations for manufacturing and marketing. The letters are not legally binding, but the agency can take companies to court if they are ignored.”