Amgen and AstraZeneca’s (AZ) experimental asthma drug tezepelumab has scored a phase III win in severe, uncontrolled asthma.

Tezepelumab is designed to block the action of thymic stromal lymphopoietin (TSLP), an epithelial cytokine that is believed to play a key role across the spectrum of asthma inflammation.

In the NAVIGATOR trial, tezepelumab added to standard of care (SoC) resulted in a statistically significant and clinically meaningful reduction in the annualised asthma exacerbation rate (AAER) over 52 weeks in the overall patient population compared to placebo plus SoC.

In a subgroup of patients with baseline eosinophil counts of less than 300 cells per microlite, the trial also met the primary endpoint – Tezepelumab demonstrated a statistically significant and clinically meaningful reduction in AAER.

Also, similar reductions in AAER were observed in the subgroup of patients with baseline eosinophil counts of less than 150 cells per microlite.

Overall, tezepelumab was found to be well tolerated in patients with severe asthma in the NAVIGATOR trial, with preliminary analyses showing no clinically meaningful differences in safety results between the treatment and placebo groups.

“Tezepelumab works differently from any other asthma biologic medicine and targets multiple inflammatory pathways that contribute to asthma symptoms and exacerbations,” said Mene Pangalos, executive vice president, BioPharmaceuticals R&D, AZ.

“Building on the broad efficacy previously seen with tezepelumab, these are exciting data that bring us one step closer to delivering a medicine to severe asthma patients, including those with low eosinophil counts,” he added.

The results from the NAVIGATOR trial are set to be presented at a forthcoming medical meeting, although AZ did not disclose which one.