April 19 (Bloomberg) -- Amgen Inc. said its anemia drug Aranesp didn't increase the risk of death for chemotherapy patients in a study, evidence that reported dangers from the medication may be limited.

Shares of Amgen, the world's biggest biotechnology company, rose 3.9 percent after the research showed no difference in survival between lung-cancer patients getting the drug and those on a placebo. Amgen sponsored the study of 600 patients, the company said in a statement today.

The results may reassure investors, doctors and patients that the drug, which generated 29 percent of the company's $14.3 billion in revenue in 2006, is safe when given for approved uses. The medication is cleared to treat anemia in chemotherapy and kidney disease patients. Research published this year linked Aranesp to deaths in patients receiving it for unapproved uses.

``It removes the worst-case scenario,'' Eric Schmidt, an analyst with Cowen & Co. in New York, said today in an interview. ``The drug isn't going away.''

The studies contributed to a 12 percent drop in the value of Amgen's stock this year through yesterday. The company, based in Thousand Oaks, California, delayed its report on first-quarter earnings, which were originally scheduled for today, so it could release the lung-cancer study. Amgen will announce financial results on April 23.

The shares of Amgen rose by $2.31 to $62.32 at 4:01 p.m. New York time in Nasdaq Stock Market composite trading. The gain was the biggest in 3 1/2 months.

Sales of $4.12 Billion

Aranesp, with $4.12 billion in sales last year, is Amgen's top-selling product.

In January, Amgen reported that cancer patients not getting chemotherapy or radiation had a higher risk of dying if treated with Aranesp. Full results from that study released last week showed that one in four cancer patients given Aranesp died after 19 weeks.

Higher deaths were also linked to Aranesp in a Danish study of head and neck cancer patients undergoing radiation. The December report was released in February.

``With many negative trial results in other oncology settings over the last few months, we think investors were largely extrapolating those experiences onto this study,'' said Christopher Raymond, an analyst with Robert W. Baird in Chicago, in an investment note. ``Today's news translates into a higher likelihood that Aranesp use in oncology stabilizes.''

Amgen's Aranesp and an older version, Epogen, and similar anemia medications, including Johnson & Johnson's Procrit, have come under scrutiny from lawmakers and regulators because of safety concerns raised in clinical trials.

Genetically Engineered

Procrit, Epogen and Aranesp are genetically engineered versions of a protein called erythropoietin that stimulates production of red-blood cells, which carry oxygen through the blood. People with anemia have low counts of red blood cells.

Studies have found that higher-than-approved doses of the drugs increased the risk of death, blood clots, strokes and heart attacks in those with chronic kidney failure, according to the U.S. Food and Drug Administration. On March 19, the FDA ordered stronger warnings on the drugs about health risks when the medications are given in ways not approved by the agency.

A panel of expert advisers to the FDA is scheduled to meet on May 10 to discuss the safety of anemia drugs.

Lawmakers' Questions

Research linking higher doses of anemia medications prompted lawmakers to question Medicare's policy on the medications. Last December, former Republican House Ways and Means Committee Chairman Bill Thomas convened a hearing on the subject.

A report in the Journal of American Medical Association this week found that for-profit dialysis centers prescribed Amgen's Epogen at higher levels than nonprofit centers. That spurred the committee's current chairman, Representative Pete Stark, a Democrat, to urge colleagues in a letter today to revise Medicare's payment system to eliminate the financial incentive of for-profit facilities.

Amgen's anemia drug sales may still be threatened by Medicare payment cuts, Geoffrey Porges, an analyst with Sanford C. Bernstein in New York said today in an investment note.

``The pressure on Medicare is clearly building and we expect significant changes to reimbursement for EPO in dialysis within the next 12 to 18 months,'' Porges said.

To contact the reporters on this story: Robert Greene in Washington at rgreene2@bloomberg.net; Angela Zimm in Boston azimm@bloomberg.net.

Last Updated: April 19, 2007 18:24 EDT