An experimental therapy being developed by AstraZeneca and its biologics research and development arm MedImmune has failed to hit key targets in two Phase III trials.

In the Stratos 2 trial, tralokinumab, an anti-interleukin-13 (IL-13) human monoclonal antibody, failed to significantly reduce the annual asthma exacerbation rate (AAER) in patients with severe, uncontrolled asthma and elevated levels of a biomarker for airway inflammation compared to placebo.

In the TROPOS study, tralokinumab failed to achieve a statistically-significant reduction in oral corticosteroid (OCS) use when added to the standard of care, in patients dependent on OCS.

Earlier this year, AZ said the Phase III STRATOS 1 study did not meet its primary endpoint of a significant reduction in the AAER in the overall population of severe, uncontrolled asthma patients, compared with placebo.

However, it had been hoping that the drug would show efficacy for the sub-population of patients with the elevated biomarker associated with increased IL-13 activity tested in Stratos 2.

Sean Bohen, AZ’ chief medical officer and vice president, Global Medicines Development, said the results were disappointing. “We had hoped that tralokinumab would benefit patients with severe asthma, which is a complex disease with limited treatment options today.”

On the plus side, safety and tolerability findings in the two trials were consistent with those observed in previous trials with tralokinumab, AZ said, and also noted that full data will be presented at a forthcoming medical meeting.

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.