Respiratory medicine company GlaxoSmithKline plc (LSE:GSK)(NYSE:GSK) reported on Tuesday the receipt of approval from the US Food and Drug Administration (FDA) for Nucala (mepolizumab) for the first targeted treatment for eosinophilic granulomatosis with polyangiitis (EGPA), previously known as Churg-Strauss syndrome.

EGPA is a chronic rare disease that is caused by inflammation in the walls of small-to-medium sized blood vessels (vasculitis). The mean age of diagnosis is 48 years and can result in damage to lungs, sinuses, skin, heart, gastrointestinal tract, nerves as well as other organs.

According to the company, mepolizumab is an interleukin-5 (IL-5) antagonist and a targeted biologic therapy developed to treat diseases which are driven by inflammation linked to higher-than-normal eosinophils (a type of white blood cell), being present in the blood.

This US FDA approval for the treatment of EGPA is based on results from the company's pivotal, 52-week, Phase III MIRRA study that was conducted in collaboration with the National Institute of Allergy and Infectious Diseases, part of the US National Institutes of Health.

Additionally, the MIRRA study evaluated the efficacy and safety of 300mg of mepolizumab administered subcutaneously every four weeks versus placebo as add-on therapy to standard of care (corticosteroids plus or minus immunosuppressants) in 136 patients with relapsing and/or refractory EGPA, said the company.

Both co-primary endpoints (accrued time in remission and proportion of patients achieving remission at both weeks 36 and 48) and all six secondary endpoints (investigating relapse, remission and corticosteroid use) were statistically in favour of mepolizumab. Nucala is now available in the US for EGPA, concluded the company.