The warnings approved by the Food and Drug Administration state that the company's drugs increased death and accelerated tumor growth in patients with early stage breast cancer and cervical cancer. Earlier labeling warned of similar risks in other types of cancer.
The changes apply to Thousand Oaks, Calif.-based Amgen's Aranesp and Epogen, as well as Johnson & Johnson's Procrit. The drugs treat the blood-disorder anemia in patients with kidney failure and those on chemotherapy. Amgen manufacturers all three, though New Brunswick, N.J.-based J & J sells Procrit.
The language states that the problems occurred when doctors treated patients with elevated levels of the drugs, which increase red blood cell levels.
The action came less than a week before a meeting where government advisers are scheduled to review the risks of the blockbuster medications.
Since FDA began scrutinizing the drugs last March, shares of Amgen have sunk 27 percent. U.S. sales of its anemia treatments fell more than 10 percent to $6.3 billion for the year.
Wall Street analysts expect sales to fall further in 2008 following next week's review by FDA's cancer experts. The panel could recommend halting use of the drugs for certain types of cancers, or in all cancer patients. Recommendations will not apply to Amgen's Epogen, which is used almost exclusively by kidney failure patients on dialysis.
If FDA removes only some cancer indications, Amgen's anemia drug sales could lose between $150 million to $250 million for 2008, according to estimates by Goldman Sachs' analyst May-Kin Ho.