UPDATE 2-U.S. calls for new warnings on Genentech skin drug

(Adds company comment, updates shares, adds background, byline)

By Susan Heavey

WASHINGTON, Oct 16 (Reuters) - U.S. health regulators have ordered strong black-box warnings for Genentech Inc's DNA.N psoriasis drug, Raptiva, saying patients given the once-weekly injections are at risk for life-threatening infections.

The U.S. Food and Drug Administration said the new warnings, announced on Thursday, will alert doctors and patients to the risk of a rare brain infection known as progressive multifocal leukoencephalopathy (PML) and other serious infections.

Raptiva, which is approved to treat moderate to severe forms of the scaly skin condition in adults, can also increase the risk of bacterial sepsis, viral meningitis and invasive fungal disease, the FDA said in a statement.

"Doctors and other prescribers should carefully evaluate and weigh the risk/benefit profile of Raptiva for patients who would be more susceptible to these risks," Janet Woodcock, head of the FDA's Center for Drug Evaluation and Research, said.

The agency called for the new warnings after receiving reports of Raptiva patients who were hospitalized, some of whom died, it said. FDA spokeswoman Rita Chappelle said she could not say how many reports the agency had received.

Genentech spokeswoman Krysta Pellegrino said the biotech was only aware of one reported case of PML that the company announced earlier this month. That patient, a 70-year-old who received Raptiva for more than four years, has since died, Pellegrino said.

She added the warning would immediately be added to the drug's packaging and that the company would send doctors a letter notifying them of the change.

Analysts have said they did not expect the reported case to significantly impact sales of Raptiva, also known by its chemical name efalizumab.

The drug saw third-quarter sales of $28 million, or about 1 percent of the company's sales, Pellegrino said.

After the FDA announcement, which happened minutes before U.S. financial markets closed, shares of Genentech were off more than 2 percent in after-hours trading after earlier closing up 0.5 percent, or 43 cents, at $81.93 on the New York Stock Exchange.

Shares of Xoma Ltd. (XOMA.O), which helped develop the drug and received sales royalties, were down 16 percent in after-hours trading after earlier closing up more than 19 percent at $1.49 on the Nasdaq.

Last month Genentech revised a warning on another drug, Rituxan, to include information about a rheumatoid arthritis patient who died from PML. The brain infection was already noted as a possible risk with that drug, also known as rituximab. (Editing by Andre Grenon and Bernard Orr)