UPDATE 3-Amgen, Amerisource sued over drug kickback scheme

* 14 states, Washington D.C., allege Aranesp kickbacks

* States say Medicaid overcharged, weekend retreats given

* AmerisourceBergen says complies with Justice subpoena

* Amgen, AmerisourceBergen to defend themselves

* Shares of Amgen, AmerisourceBergen fall (Adds background, details from lawsuit)

By Jonathan Stempel

NEW YORK, Oct 30 (Reuters) - Biotechnology giant Amgen Inc (AMGN.O) and drug wholesaler AmerisourceBergen Corp (ABC.N) were sued on Friday by 14 U.S. states and the District of Columbia over an alleged kickback scheme designed to boost sales of Amgen's popular anemia drug, Aranesp.

New York Attorney General Andrew Cuomo announced the lawsuit, which was filed in federal court in Boston.

It joins a related whistleblower lawsuit filed in the same court in 2006 and is one of many lawsuits accusing drugmakers of illegally marketing their products.

"Drugs should be prescribed to patients on the basis of need, effectiveness, and safety, not on a corporate giant's promise of an all-expense paid vacation," Cuomo said in a statement.

He said Amgen's bribing of doctors "left taxpayers footing the bill for free drug samples."

The lawsuit alleges Amgen and two AmerisourceBergen units, International Nephrology Network and ASD Healthcare, conspired to encourage doctors to bill third party payers such as Medicaid for Aranesp that was provided at no cost.

It said this resulted in "thousands of false claims to be paid by the state Medicaid programs that were ineligible for payment," causing millions of dollars of damages.

The lawsuit also alleges that kickbacks, including "sham consultancy agreements and weekend junkets," were made to medical providers to induce them to buy and prescribe Aranesp.

ARANESP SALES FALLING

Amgen spokesman David Polk said the allegations lack merit and that Thousand Oaks, California-based Amgen expects its employees to follow a code of conduct.