Amgen Inc. has added a warning to its anemia drug Aranesp after studies showed high doses of similar drugs can cause blood clots and death. Aranesp is widely used to treat anemia in adult cancer patients as well as chronic kidney disease. Some researchers had thought elevating hemoglobin might boost the effectiveness of chemotherapy and radiation to fight cancer. The company said in a Jan. 11 letter to health professionals that two clinical studies revealed the complications when similar drugs were used to raise hemoglobin levels above recommended levels. A Food and Drug Administration panel of outside experts last year called for more study of the risks of the anemia drugs, including faster tumor growth and more blood clots. The company said it would not change its dosage recommendations. Story here.