Emboldened by positive phase III data, AstraZeneca has said it will press on with plans to file its benralizumab candidate for severe asthma in the US and EU before the end of the year.
The UK pharma group reported the results of two studies at the European Respiratory Society (ERS) in London, which showed the interleukin-5 (IL-5) inhibitor was able to reduce attacks and improve lung function when used as an add-on therapy in individuals with severe asthma.
The SIROCCO and CALIMA trials – which have also just been published in The Lancet – showed that benralizumab could curb asthma exacerbations by up to 51% and improved lung function (as measured by forced expiratory volume) within four weeks of starting treatment.
The antibody was also shown to improve asthma symptoms such as wheeze, cough, chest tightness and shortness of breath, while side effects were similar to those seen in patients randomised to placebo in the two trials.
AZ is playing catch-up with benralizumab, as there are already two IL-5 inhibitors on the market – GlaxoSmithKline’s Nucala (mepolizumab) and Teva’s Cinqaero (reslizumab) – for asthma characterised by high levels of eosinophils in the blood, a biomarker for severe disease.
As a late entrant into the market AZ will be hoping for some data that differentiates its candidate from its rivals. An editorial in The Lancet accompanying the studies suggests that the three IL-5 inhibitors appear to demonstrate a consistent effect, which is encouraging as clinicians get used to treating asthma patients with the new class.
Nucala is expected to benefit from its first-to-market status, with analysts predicting sales of $500m to $1bn given the seriousness of uncontrolled asthma. Its dosing – by subcutaneous injection every four weeks – is seen as an advantage over Cinqaero, which has to be delivered intravenously.
Benralizumab is also dosed subcutaneously, and critically the new trial data suggest that it is equally effective when given every four or eight weeks, which could make it appealing for patients who dislike injections.
AZ could potentially also benefit from a decision to enrol a broader patient population into its pivotal trials, as it chose not to select trial subjects with elevated eosinophils, although this will depend on final labelling and whether healthcare payers opt to use eosinophil levels as a condition of treatment.
Interestingly, AZ’s press release to announce the SIROCCO and CALIMA results emphasises the efficacy of benralizumab “in severe asthma patients with an eosinophilic phenotype, as indicated by the presence of eosinophils in their blood”.
The drug can offer “a meaningful treatment option for patients as evidenced by reductions in exacerbations, improvement in lung function and symptoms, with the promise of fewer doses a year,” commented Sean Bohen, AZ‘s chief medical officer.
He also alluded to the fact that benralizumab has a slightly different mechanism of action to its rivals. The antibody binds to a subunit of the IL-5 receptor rather than targeting the IL-5 cytokine directly, which – in theory at least – could mean it works regardless of eosinophil levels in the blood.
How the drug fares against its rivals remains to be seen, but at the moment analysts are predicting sales in the region of $500m, well shy of AZ’s own forecasts of $2bn.