GlaxoSmithKline’s Nucala has been approved by the US Food and Drug Administration (FDA) for the treatment of hypereosinophilic syndrome (HES), making it the first biologic approved in this indication.

Nucala (mepolizumab) has been indicated for use in the US for the treatment of adult and paediatric patients aged 12 years and older with HES for six months without an identifiable non-haematologic secondary causes.

The FDA approval is based on data from a clinical development programme that included positive results from a pivotal phase 3 study. The study showed 50% fewer patients experienced a HES flare when treated with Nucala, compared to placebo, when added to standard of care treatment over the 32-week study period.

HES is a rare and under-diagnosed disorder which is characterised by persistent and market overproduction of eosinophils, a type of white blood cell.

Complications from HES range from fever and malaise to respiratory and cardiac problems, and if left untreated, the symptoms become progressively worse and can become life-threatening.

“HES is a complex, life-threatening condition that impacts nearly 5,000 patients in the US. Today’s approval gives these patients access to a biologic treatment for the first time and demonstrates our commitment to maximising Nucala’s impact on eosinophil-driven diseases,” said Hal Barron, chief scientific officer and president R&D at GSK.

Nucala is already approved as an add-on maintenance therapy for severe eosinophilic asthma and for the treatment of eosinophilic granulomatosis with polyangiitis (EGPA), and is also being investigated in several eosinophil-driven diseases.