AstraZeneca and Amgen have received breakthrough therapy designation for tezepelumab to treat severe asthma, irrespective of an eosinophilic phenotype.

The indication allows use for patients on inhaled corticosteroids (ICS) and long-acting beta2-agonists therapy (LABA) with or without oral corticosteroids (OCS) and other asthma controllers.

Tezepelumab is designed to block thymic stromal lymphopoietin (TSLP), an epithelial cytokine associated with the initiation and persistence of airway inflammation.

Inhibition of TSLP is expected to prevent pro-inflammatory cytokines generation by immune cells, in turn preventing asthma exacerbations and allowing better disease control.

The activity of the drug in early stages of the inflammation cascade may allow treatment of wide patient populations with severe, uncontrolled asthma.

AstraZeneca chief medical officer and Global Medicines Development executive vice-president Sean Bohen said: "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.

"The breakthrough therapy designation will help us bring tezepelumab to patients as quickly as possible."

The FDA reviewed data from the Phase IIb PATHWAY clinical trial that assessed efficacy and safety of three tezepelumab dose regimens as an add-on therapy.

Data showed significant decrease in the annual asthma exacerbation rate, when compared with placebo. The rates were 62%, 71% and 66%, respectively, for 70mg, 210mg and 280mg doses.

Amgen Research and Development executive vice-president David Reese said: "The Phase IIb PATHWAY trial data demonstrated tezepelumab’s promise as a novel therapeutic option for a broad population of patients with severe asthma, including those ineligible for currently approved biologic therapies."

AstraZeneca and Amgen are currently evaluating tezepelumab in two studies in the Phase III PATHFINDER trial programme.

NAVIGATOR studies the efficacy and safety of regular administration of tezepelumab for 52 weeks in patients with severe asthma that cannot be adequately controlled by ICS.

SOURCE studies the drug’s efficacy for 48 weeks in patients who require continuous treatment with ICS in combination with LABA and chronic maintenance OCS therapy.