Amgen Warns About Higher Doses of Anemia Drugs

Amgen Inc. has added a warning to its anemia drug, Aranesp, for kidney dialysis and cancer patients after studies on similar drugs showed higher doses can cause blood clots and death, the company said a letter released on Friday.

The world’s largest biotechnology company said the new warning stems from studies done outside the United States on two other anemia drugs — Eprex, made by Johnson & Johnson unit Ortho Biotech Products L.P., and NeoRecormon, made by Roche Holding AG .The studies revealed major complications, including blood clots and death, when doctors used anemia drugs to try to boost hemoglobin levels beyond what was recommended, the letter said.A U.S. 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. Some researchers had thought elevating hemoglobin might boost the effectiveness of chemotherapy and radiation to fight cancer.Amgen spokeswoman Trish Hawkins said the FDA asked the company to add the trial information and warning to Aranesp, which the company is also studying for use in improving cancer treatment through increased hemoglobin levels.”At this point, we know we have not observed this in our oncology trials,” Hawkins said of the blood clot problems.Amgen shares were off 26 cents at $63.63 in afternoon trading on the Nasdaq.”An increased incidence of thrombotic events has been observed in patients treated with erythropoietic agents,” the new label reads, adding that “a randomized controlled study with “another erythropoietic product” was “associated with a higher rate of fatal thrombotic events.”Along with Ortho Biotech’s drug Procrit, Aranesp is a bioengineered version of a human protein, erythropoietin, that stimulates production of red blood cells. The combined sales of the two anemia drugs amount to several billion dollars a year.Aranesp is the Amgen’s follow up to its earlier anemia drug called Epogen.Ortho Biotech in August sent physicians a letter similar to that of Amgen, which the FDA released in December.Anemia, a lower than normal number of red blood cells, is usually measured by a decrease in the amount of hemoglobin, a pigment in those cells that transports oxygen. Normal levels of hemoglobin are 12 to 18 grams per deciliter of blood.The studies allowed hemoglobin levels to rise above 12, Amgen said.Amgen, in its letter, said the new warning did not change its current recommendations on how doctors should use the drug. “Amgen continues to recommend that the target hemoglobin should not exceed 12 grams per deciliter,” the letter said.(Source: Reuters Health, January 2005)