New York, California, and 13 other states are accusing biotech giant Amgen Inc. of offering kickbacks to medical providers to boost sales across the country of its anemia drug Aranesp. In a suit filed in federal court in Massachusetts, the states accuse Amgen sales representatives of encouraging doctors and other healthcare providers to bill insurers for Aranesp that the practitioners received free from the company, according to a statement issued by New York Attorney General Andrew Cuomo. The practice allegedly cost taxpayer-funded Medicaid programs and other insurers millions of dollars in overpayments.