A BTD is designed to expedite the development and review of medicines that are intended to treat a serious and have shown promise in early-stage clinical trials.
Tezepelumab was awarded the designation after data from a phase IIb trial showed a significant reduction in the annual asthma exacerbation rate compared with a placebo.
Current treatments only target a certain subset of patients but Astra reckons its drug can treat all sufferers.
Chief medical officer 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.”
AstraZeneca shares edged 0.2% to 5,645p on Friday morning.