AstraZeneca

(AZN) - Get Report

began running full-page ads in major newspapers Tuesday defending its cholesterol drug Crestor.

The company said it was acting in response to comments made by an FDA official Nov. 18 during a Senate Finance Committee hearing focusing on how the Food and Drug Administration and

Merck

(MRK) - Get Report

handled the withdrawal of the arthritis drug Vioxx from the market.

During the course of questioning, the FDA official, Dr. David J. Graham, who had conducted studies on Vioxx, also said that five other drugs now on the market merited greater scrutiny by the companies and the FDA. One of those drugs was Crestor, which was approved by the FDA in August 2003.

"There was a great deal of misinformation," said Emily Denney, a spokeswoman for AstraZeneca, on Tuesday. "The safety profile is in line" with other cholesterol drugs known as statins.

Despite comments last week from higher-ranking FDA officials repudiating Dr. Graham's comments about the safety of Crestor and the other drugs, Denney said her company "felt compelled to communicate the facts about this medicine ... and encourage patients to talk to their doctors."

Other FDA officials said last week that Dr. Graham was speaking only for himself, adding that the agency views Crestor as safe when taken as directed. AstraZeneca fired off two statements within 24 hours of Graham's testimony. "We have been assured today at senior levels in the FDA that there is no concern in relation to Crestor's safety," the company said Nov. 19.

Tuesday's advertisement says, in part: "You can be assured that at AstraZeneca, patient safety is our No. 1 priority. ... The scientists at the FDA who are responsible for the approval and ongoing review of Crestor have, as recently as last Friday, publicly confirmed that Crestor is safe and effective."

The advertisement continues that "the concerns that have been raised have no medical or scientific basis."

Crestor's competitors include the market leader Lipitor, made by

Pfizer

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; Zocor, from

Merck

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; Pravachol from

Bristol-Myers Squibb

(BMY) - Get Report

; and Vytorin from Merck and

Schering-Plough

(SGP)

. Vytorin combines Merck's Zocor and Schering-Plough's Zetia.

At the hearing last week, Graham suggested that Crestor patients might have had a higher rate of kidney problems and a rare, potentially dangerous muscle disorder. He alluded to an upcoming article in the

Journal of the American Medical Association

as containing new information about Crestor and statin safety. But that article, which was released online Monday, didn't address Crestor.

The article, of which Graham was the lead author, concluded that three statins -- Lipitor, Zocor and Pravachol -- had equally very low rates of the muscle disorder called rhabdomyolysis. The article said the risk of the muscle disorder was approximately a dramatic 1 in 10 for patients who took Baycol, which was pulled from the market three years ago.

Baycol was made

Bayer,

(BAY)

. The FDA received reports linking 31 deaths from the muscle disease to the drug. Baycol was launched in the U.S. in 1997.

AstraZeneca has been the subject of frequent criticism by the Public Citizen Health Research Group, which has called on the FDA to ban Crestor, alleging that the drug has been linked to an unacceptable rate of side effects. The company has repeatedly defended itself against the group's claims.

AstraZeneca's stock was recently off 16 cents, or 0.4%, to $40.07.