Prospects for drugs targeting interleukin-13 for asthma treatment have taken another knock after AstraZeneca’s tralokinumab failed a phase III trial.
The first of two late-stage studies of the IL-13 inhibitor – STRATOS 1 – failed to meet its primary objective of showing a significant reduction in the number of asthma attacks suffered over a year compared to placebo in patients with severe, uncontrolled asthma, despite the use of anti-inflammatory therapies such as corticosteroids.
IL-13 is thought to be involved in the onset of asthma attacks as elevated levels of the cytokine seem to tally with severe, frequent attacks and impaired lung function in patients.
The Anglo-Swedish pharma group is now waiting for the results of the second phase III trial (STRATOS 2), due later this year to gauge whether there is any point in pursuing development of tralokinumab for severe asthma. It says it will look at the totality of data from both studies to see if there is a patient group that can benefit from the drug, such as those with elevated levels of IL-13 at enrolment.
It looks increasingly like a lost cause as AZ already reported disappointing phase IIb data with tralokinumab, and last year Roche reported disappointing results with its anti-IL-13 candidate lebrikizumab, with one trial meeting its objectives but a second identical study failing to show a significant impact on asthma attacks. Meanwhile Pfizer also had an anti-IL-13 drug called anrukinzumab in asthma trials but killed off that project in 2014.
With tralokinumab looking decidedly shaky, AZ’s biggest hope of a new launch in its respiratory portfolio is benralizumab, an anti-IL-5 drug for severe asthma currently awaiting regulatory approval but will have to play catch-up in the market with two already-marketed IL-5-targeting drugs – GlaxoSmithKline’s Nucala (mepolizumab) and Teva’s Cinqaero (reslizumab).
Last year AZ’s respiratory pipeline took a further knock when it halted a phase IIa trial of a Synairgen-partnered inhaled interferon beta formulation (AZD9412) for asthma after deciding it was unlikely to give conclusive results.