(Corrects to remove 'not' in first paragraph)

(Reuters) - Shares of Biogen Inc rose 4% in premarket trade on Monday as an unanimous backing of the company's Alzheimer's drug Leqembi by the U.S. regulator's advisers eased concerns that a traditional approval for the treatment will come with major new safety warnings.

The U.S. Food and Drug Administration had asked its panel of experts to weigh in on the side effects of Leqembi in certain patients, like those taking drugs that prevent blood clots.

But the advisers said that these could be managed and were balanced against the benefits provided by the drug, which was developed by Biogen and partner Eisai Co.

"We believe use will largely be left in the hands of physician-patient discussions," said William Blair analyst Myles Minter.

Minter added that he expected warnings listed in Leqembi's product information label under accelerated approval to remain largely unchanged if a regular approval is granted.

Traditional approval by the FDA, which is expected by July 6, is likely to expand Medicare payment for the treatment. That would also make Leqembi the first disease-modifying drug ever to achieve the regulatory milestone.

Biogen's shares trade at 4.71 times Wall Street's estimates for sales in the next 12 months, compared to 2.89 for rival Bristol Myers Squibb and 3.61 times for Gilead Sciences Inc.

(This story has been corrected to remove 'not' in paragraph 1)

(Reporting by Leroy Leo in Bengaluru; Editing by Shailesh Kuber)