Pfizer Inc. says the Food and Drug Administration on Tuesday approved its new drug to treat a rare form of blood and bone marrow cancer.

Pfizer's Bosulif is a daily pill to treat patients with a specific genetic variation. The disease is one of four types of the blood cancer, and accounts for about 15 percent of leukemia cases.

The disease, which usually affects seniors, causes the bone marrow to produce unhealthy that do not grow and die like normal cells. Instead, the cells buildup in the bone marrow and crowd out healthy cells that are needed to fight off infections.

An estimated 5,430 people will be diagnosed with this year, according to the FDA.