The condition, formerly known as Churg-Strauss Syndrome, is characterised by asthma, high levels of eosinophils, and inflammation of small- to medium-sized blood vessels affecting various organ systems in the body, including lungs, skin, heart, gastrointestinal tract and nerves. Without treatment, the disease may be fatal.

Fasenra (benralizumab) induces rapid and near-complete depletion of eosinophils in the blood and has proven efficacy in severe, eosinophilic asthma, which suggests it may also benefit patients with EGPA.

It is also AstraZeneca’s first respiratory biologic and is currently approved as an add-on maintenance treatment for severe, eosinophilic asthma in the US, EU, Japan and several other regions.

"Our clinical trials for Fasenra in severe, eosinophilic asthma show it depletes eosinophils and we are exploring the potential of this medicine to address unmet medical needs in other eosinophil-driven diseases," noted Sean Bohen, AZ’ chief medical officer.

The FDA only grants ODD status to medicines intended for the treatment, diagnosis or prevention of rare diseases or disorders that affect fewer than 200,000 people in the US, or that affect more than 200,000 persons but are not expected to recover the costs of developing and marketing a treatment drug. ODD provides a incentive for sponsors to develop products for rare diseases.