UPDATE 2-U.S. FDA warns Gilead, Biogen over drug promotions

* Letters target Gilead’s Truvada, Biogen’s Tysabri

* FDA objects to print ad, Web video (Adds company comment, background)

WASHINGTON, April 7 (Reuters) - U.S. health regulators warned Gilead Sciences GILD.O, Biogen Idec BIIB.O and other drugmakers on Wednesday over misleading promotions for various products.

In letters to the companies, the U.S. Food and Drug Administration warned Gilead over a direct-to-consumer print advertisement for its HIV drug, Truvada. It also warned Biogen over a webcast touting its multiple sclerosis therapy, Tysabri.

The FDA cited a multiple-page ad for suggesting “that Truvada is better or more effective than has been demonstrated.”

The ad shows photos of a woman taking the drug at various stages of life who “appears to be happy and in good health,” according to the letter. But the FDA said those claims could lead people to think they can manage their disease on a long-term basis when the drug was studied for three years.

While small text in the ad mentions the study, it “does not mitigate the overwhelming impression created by the prominent images,” the FDA wrote.

A webcast video for Biogen’s Tysabri “is false or misleading because it minimizes important risks associated with the use of Tysabri and omits the drug’s approved indication.”

“We are particularly concerned with this webcast because it presents numerous statements that seriously minimize the risk of PML (progressive multifocal leukoencephalopathy),” a known issue with the drug, the FDA said.

The agency also issued a letter to privately held Aton Pharma Inc as well as a previously released warning letter to Salix Pharmaceuticals SLXP.O.

Gilead spokeswoman Erin Rau said the company took the warning seriously and would respond to the FDA directly.

Representatives for Biogen did not return a phone call seeking comment.

Shares of Gilead and Biogen closed down less than 1 percent on Nasdaq.

Reporting by Susan Heavey; Editing by Richard Chang