As reported in GSK, the FDA has just granted priority review to Nucala (mepolizumab), a targeted biological treatment to help patients with hypereosinophilic syndrome (HES). If the medication is accepted, it will be the first targeted biologic therapy approved for the potentially fatal disease.

Hypereosinophilic Syndrome

Hypereosinophilic syndrome (HES) is a rare blood disorder characteristically causing patients to have too many eosinophils, a type of white blood cell.  Symptoms can include skin rashes, fever, respiratory issues, fatigue, memory loss, brain damage, diarrhea, lung disease, cardiac problems, and nerve damage. The disease is progressive, and if unaddressed can be fatal. Because the disease is under diagnosed, it’s hard to know the true prevalence, but it’s estimated to effect 1 to 2 in a million people.

Nucala

The drug will additionally benefit from receiving Fast Track and Orphan Drug designations, which are intended to help drugs targeting rare disease which otherwise may be unaffordable. They are reserved to boost potential options that could help patients with an unmet need.

The phase 3 study was randomized, double-blind, and placebo controlled. It was conducted on 108 patients over six months, who took either the drug or a placebo every four weeks. The scientists met the goal they set out to achieve- with patients experiencing a statistically significant reduction of flare ups or withdrawal following the study. 

Nucala has already been approved by the FDA to treat severe eosinophilic asthma and eosinophilic granulomatosis with polyangiitis (EGPA), though only as additional medication. However, the drug is now being looked at to treat a host of eosinophil-driven diseases. Now, it could potentially meet the high unmet needs of patients with HES.