On Thursday, an FDA panel recommended further study and more restrictive labeling for anemia drugs, including Johnson & Johnson's (NYSE:JNJ) Procrit, and Amgen (NASDAQ:AMGN) blockbusters Aranesp and Epogen, which produced combined sales of more than $6 billion for the company in 2006. This follows a black box warning from the agency in March, addressing concerns that anemia drugs are being used too aggressively in some patients and studies that showed an increased risk of death in cancer patients not receiving chemotherapy.

Shares of Amgen are trading at their lowest point in a few years on the news, although the Food and Drug Administration will have the final say on the class of related anemia drugs known as epoetins, which stimulate red blood cell production. These drugs are approved to treat anemia in cancer patients receiving chemotherapy and in patients with kidney failure. Critics contend that physicians are overusing the drugs to make more money, because the drugs are typically administered at the doctor's office. Another FDA panel meeting is scheduled for later this year to discuss the risks of the anemia drugs in patients with kidney failure.

Last week, the FDA panel voted unanimously (17-0) for more clinical testing, and 15-2 to recommend stronger warnings on the anemia drugs. Amgen is taking a hit on two fronts from the vote: First, it faces the increased cost, in time and money, of conducting additional clinical trials, and second, it faces the prospect of doctors using its anemia drugs less until the issues are resolved.

As Amgen's stock falls, the company is starting to resemble an aging big pharmaceutical company instead of a cutting-edge biotech. The $6.6 billion in combined sales last year for Aranesp and Epogen made up almost half of the company's total revenues. Future restrictions on these drugs could lead to the shares continuing to struggle, and Amgen might begin to search for promising acquisition targets to diversify and bolster its pipeline and growth prospects.

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Fool contributor Mike Havrilla, R.Ph., B.S., Pharm.D., is a Rite Aid pharmacist who lives, writes, works, and enjoys running on the streets and trails in Portage, Pennsylvania. He invites your comments and feedback. Mike does not have a position in any company mentioned in this article. Johnson & Johnson is an Income Investor selection. The Fool has a disclosure policy.