WASHINGTON (AP)  On Friday, federal regulators approved a biotechnology drug from Amgen that treats a rare blood-clotting disorder.

The Food and Drug Administration approved the drug, Nplate, for patients with a disorder that causes the body to attack its own platelets, tiny components of blood that help with clotting. The condition, which can cause bruising and bleeding after minor injuries, affects about 140,000 people.

Regulators said Nplate is the first drug that directly encourages platelet production by stimulating the patient’s bone marrow.

The F.D.A. approved the drug based on two studies that showed that it increased patients’ platelet count over six months. Patients received weekly injections of Nplate, a genetically engineered version of the protein that encourages platelet production.