Amgen data debate.

Amgen Inc., skilled in using post-approval clinical studies to promote wider usage of its products, may get stung by a recent study that questions the safety of higher dosing for its flagship anemia treatment.

Thousand Oaks-based Amgen and Johnson & Johnson separately sell a red blood cell-boosting drug, known generically as epoetin, under the respective brand names Epogen and Procrit for treating anemia caused by kidney disease and chemotherapy. Worldwide sales of Amgen's anemia line, which includes an extended-use version called Aranesp, are expected reach around $10 billion this year.

A New England Journal of Medicine study last month suggested that kidney patients who received higher does of epoetin than advised on the drug's government-approved label were more likely to die or suffer heart problems than those receiving lower doses.

Though drug companies cannot market products for uses and doses beyond the U.S. Food and Drug Administration-approved label, physicians regularly experiment in both areas based on post-clinical studies, often company sponsored, that are published in medical journals or presented at professional meetings.

An expert panel of doctors for the National Kidney Foundation is expected to review its epoetin dosing guidelines early next year, based on the New England Journal study. The foundation's guidelines encourage more aggressive treatment than FDA recommendations, and some doctors have suggested that Amgen had unduly influenced the panel in the past, an allegation the company denies.

The company said in a statement that while it does provide unrestricted medical education grants to groups like the foundation, Amgen itself promotes use of its drugs in accordance with FDA guidelines. The FDA issued a new dosing warning to doctors following the journal article.

Staff reporter Deborah Crowe can be reached at [phone], ext. 232, or at [e-mail].