AstraZeneca’s tralokinumab has failed to significantly reduce the rate of annual exacerbations in patients with uncontrolled asthma taking part in a late-stage trial.

The Phase III STRATOS 1 study did not meet its primary endpoint of a significant reduction in the annual asthma exacerbation rate (AAER) in the overall population of severe, uncontrolled asthma patients, compared with placebo.

However, there could still be path forward for the drug - an anti-IL-13 human immunoglobulin-G4 monoclonal antibody that blocks binding and signalling of IL-13 to IL-13 receptors - in this setting.

In a planned analysis of data from STRATOS 1, a clinically-relevant reduction in AAER was observed in a sub-population of patients with an elevated biomarker associated with increased IL-13 activity.

This sub-group of patients will now be the focus for the future analysis of STRATOS 2, the second ongoing pivotal Phase III trial in the programme, a readout from which is expected in the second half of this year.

Also on the plus side, the safety and tolerability profile of tralokinumab in STRATOS 1 was found to be consistent with that observed in previous trials.

Asthma affects 315 million individuals around the globe, with up to 10 percent having severe forms of the disease, which may be uncontrolled despite high doses of standard-of-care asthma controller medicines and can require the use of chronic oral corticosteroids.