India, Sept. 28 -- The U.S. Food and Drug Administration approved the first drug to treat adults and children aged 12 years and older with hypereosinophilic syndrome (HES) for six months or longer without another identifiable non-blood related cause of the disease. GlaxoSmithKline's Nucala (mepolizumab) is the first FDA-approved drug in nearly 14 years to treat this group of rare and debilitating blood diseases and other rare conditions.

HES is a heterogeneous group of rare disorders associated with persistent eosinophilia (higher than normal levels of a type of disease-fighting white blood cell) with evidence of organ damage. Signs and symptoms vary significantly based on which parts of the body are affected.

Although any organ system ...