March 7 (Bloomberg) -- Amgen Inc. said U.S. regulators approved a revised warning for use of the anemia drugs Aranesp and Epogen after studies showed cancer patients on the drugs may die sooner.

The updated precaution, which also applies to Johnson & Johnson's Procrit, said the drugs ``shortened overall survival'' time in patients with certain tumors when dosed to a target level of 12 grams or more of hemoglobin for each deciliter of blood, Amgen said today in a statement. The warning also says that tumors may spread more quickly for patients on the drugs.

The warning, the most strict used by regulators, cites new evidence from a breast cancer study, called Prepare, which showed patients had a higher risk of death on Aranesp. It also notes danger for patients with cervical cancer, based on results in December from a study called GOG-191. The U.S. Food and Drug Administration has scheduled an advisory panel on March 13 to discuss risks and benefits of the products.

``It was a foregone conclusion that the FDA would have to change the label to reflect that data,'' said Bret Holley, an analyst with Oppenheimer & Co. in New York, in a telephone interview.

Although the FDA took action before the advisory meeting, Amgen and J&J may face further restrictions, such as a recommendation to lower the dose or that doctors stop prescribing the drugs for certain cancers, Holley said.

``The discussions at the panel can still take on a life of their own,'' Holley said.

Shares

Thousand Oaks, California-based Amgen rose $1.02, or 2.3 percent, to $45.20 in extended trading after the announcement. Earlier, Amgen fell 6 cents to $44.18 at 4 p.m. in Nasdaq Stock Market composite trading. J&J, based in New Brunswick, New Jersey, dropped $1.12, or 1.8 percent, to $61.51 in New York Stock Exchange composite trading.

The new warning for the anemia drugs is being added to precautions outlined in a black box at the top of prescribing information for the medicines. Amgen and J&J are also sending a letter to doctors informing them of the added warning.

Amgen, the world's largest biotechnology company, lost $29 billion in market value last year after Aranesp, its top seller, and Epogen were tied to higher risks of heart attack, stroke and death at high doses. The FDA urged doctors a year ago to use the lowest doses possible after dangers were seen in patients with kidney disease and head and neck cancer.

The anemia drugs are used to treat the weakness and fatigue of patients who have chronic kidney disease or are undergoing cancer chemotherapy. The medicines stimulate production of oxygen-carrying red blood cells.

Drug Sales

Aranesp generated $3.61 billion in worldwide sales in 2007, a 12 percent decline from the previous year. Epogen, marketed for patients on kidney dialysis, generated $2.49 billion in U.S. sales in 2007, down less than 1 percent from the prior year.

Procrit, manufactured by Amgen and identical chemically to Epogen, is marketed by J&J in the U.S. under a license. Procrit had $1.69 billion in U.S. sales in 2007, an 18 percent drop from the previous year. It is sold for people with cancer and kidney patients not on dialysis.

To contact the reporter on this story: Luke Timmerman in San Francisco at ltimmerman@bloomberg.net

Last Updated: March 7, 2008 18:01 EST