Nplate, Amgen’s drug destined for patients suffering from a rare blood disorder called chronic immune thrombocytopenic purpura (ITP), was approved by the Food and Drug Administration on Friday. The administration labeled it as safe and effective and approved it to be sold in the United States.

ITP is an illness that causes a low number of platelets in humans. The platelets are blood components that play a key role in clotting. In the cases of chronic ITP, the platelets are removed by the human body’s immune system leaving the patient's bone marrow incapable of compensating the loss. The disease, which usually causes dangerous bleeding and bruises due to minor injuries as well, affects as much as 140,000 people. About 60,000 U.S. adults suffer from chronic ITP, according to Amgen estimations.

The role of the Nplate drug, also known as romiplostim, is to stimulate the bone marrow to generate more blood platelets. The FDA approved its use only for patients suffering from chronic ITP and only if other available treatments would have failed to cure the patient. Dr. Janet Woodcock, chief of the FDA's Center for Drug Evaluation and Research, described the Nplate as a new-approach, important product that helps patients with blood disorder recover from their illness.

The FDA said it took the decision to approve Nplate after consulting data from two studies which involved 125 patients who were treated with Amgen’s drug for six months. The studies showed that those who took Nplate showed "significantly higher platelet counts and maintained those higher counts compared to those who did not receive the drug.”

However, analysts do not expect Nplate to be a big seller for Amgen. The drug is expected to cash in from $66 million to $117 million in 2009 and go as high as $200 million at some point, but that’s a small figure compared to the international biotechnology company’s last year revenue of $14.7 billion.