Human therapeutics company Amgen (NASDAQ:AMGN ) and AstraZeneca (NYSE:AZN ) Thursday jointly announced the US Food and Drug Administration's (FDA) Breakthrough Therapy Designation to expedite the development and regulatory review of tezepelumab for the treatment of patients with severe asthma without an eosinophilic phenotype.

The US FDA's Breakthrough Therapy Designation is supported by the company's tezepelumab Phase 2b PATHWAY data, which were published in the New England Journal of Medicine and presented at the European Respiratory Society International Congress in 2017. The trial showed annual asthma exacerbation rate reductions of 62%, 71% and 66% in the tezepelumab arms receiving either 70 mg or 210 mg every four weeks or 280 mg every two weeks compared to placebo, respectively.

In conjunction, tezepelumab is currently in development in the Phase 3 PATHFINDER clinical trial programme, disclosed the companies.

According to the company, tezepelumab is a potential first-in-class medicine blocking TSLP, an epithelial cytokine, critical in the initiation of airway inflammation. Blocking TSLP may prevent the release of pro-inflammatory cytokines by immune cells resulting in the prevention of asthma exacerbations and improved asthma control.

Currently, the available biologic therapies only target T2 driven inflammation, revealed the companies.

Up to 10% of asthma patients have severe asthma, which may be uncontrolled despite high doses of standard-of-care asthma controller medicines and can require the use of chronic oral corticosteroids (OCS). Severe uncontrolled asthma is debilitating with patients experiencing frequent exacerbations and significant limitations on lung function. T2 inflammation-driven asthma, which includes eosinophilic phenotype, is present in over two-thirds of patients with severe asthma.