AstraZeneca and Amgen’s tezepelumab has won breakthrough therapy status in the US for its potential to treat severe asthma without an eosinophilic phenotype.

The therapy is being developed for use in patients who are receiving inhaled corticosteroids/long-acting beta2-agonists with or without oral corticosteroids and additional asthma controllers.

The breakthrough designation is based on data from the Phase IIb PATHWAY trial, which, according to the firms, showed “a significant reduction in the annual asthma exacerbation rate compared with placebo in a broad population of severe asthma patients irrespective of patient phenotype including Type 2 (T2) biomarker status”.

T2 inflammation-driven asthma, which includes the eosinophilic phenotype, accounts for around two-thirds of severe asthma cases and is typically characterised by elevated levels of T2 inflammatory biomarkers. However, around one-third of patients do not present with increased T2 inflammation and are in need of new treatment options.

Current biologic therapies only target T2-driven inflammation, but tezepelumab has a different mode of action in that it blocks thymic stromal lymphopoietin (TSLP) - an upstream modulator of multiple inflammatory pathways.

“Tezepelumab is exciting because it has the potential to treat a broad population of severe asthma patients, including those ineligible for currently-approved biologic therapies,” said Sean Bohen, executive vice president, Global Medicines Development and chief medical officer at AZ.

“The Breakthrough Therapy Designation will help us bring tezepelumab to patients as quickly as possible.”