Senator has questions on Amgen anemia drug rebates

By Lisa Richwine

WASHINGTON (Reuters) - Sen. Charles Grassley asked Amgen Inc to explain why some doctors received higher rebates on purchases of the company's anti-anemia drug Aranesp, a letter released on Thursday said.

In a letter to the drugmaker, the Iowa Republican said data he obtained from Amgen indicated oncologists in some states had been given notably higher rebates than others for Aranesp, which is under scrutiny for safety concerns.

"The information raises questions," Grassley said in a statement.

Grassley said there were concerns doctors were profiting by getting reimbursements from the government and private insurers that were higher than their actual cost for Aranesp. Some critics have asked if rebate practices encourage overuse.

Aranesp is Amgen's top-selling drug with 2007 sales of $3.6 billion. The drug is used to treat anemia in patients with cancer and kidney disease, and is part of a family known as erythropoiesis-stimulating agents, or ESAs.

U.S. lawmakers have been investigating the marketing of ESAs by Amgen and Johnson & Johnson amid studies that found some patients given high doses died sooner or saw their cancers grow. A Food and Drug Administration advisory panel urged limits on use in cancer patients last month, and the FDA is considering that advice.

Amgen spokeswoman Kelley Davenport said the company would continue to cooperate with Grassley's inquiry.

She said Amgen, like other companies, provided rebates and discounts to customers and did not believe the practices led to inappropriate or excessive use.