AstraZeneca's self-styled 'blockbuster' benralizumab tanks in severe COPD study

AstraZeneca's headquarters in London--Courtesy of AstraZeneca

AstraZeneca was forced to concede a clinical defeat on Monday, noting that one of its top respiratory drugs in the clinic failed a study for severe chronic obstructive pulmonary disease. But while investigators also flagged a higher rate of adverse events for benralizumab than the placebo arm, the pharma giant ($AZN) shows no signs of backing away from a treatment it's billed as a potential $2 billion per year product.

COPD is a big disease target for AstraZeneca and its biologics unit MedImmune, which have been pushing hard to overcome a long record of failure in the clinic. But in the Phase IIa study with 101 patients benralizumab failed to improve the rate of acute exacerbations. And there was also a higher rate of severe treatment-emergent adverse events in the drug arm. 

Investigators, though, focused on the positive signs of an improvement in lung function, noting that an analysis of the data demonstrated improvements for patients with higher levels of eosinophils--a white blood cell linked to greater severity of attacks in COPD patients.

Eosinophils may point to a future for this drug in COPD, a crowded field in which GlaxoSmithKline ($GSK), Teva ($TEVA) and Novartis ($NVS) play a big role. GlaxoSmithKline started a Phase III study for mepolizumab in COPD patients last April as it wrapped a successful late-stage effort in asthma. And Teva's reslizumab also did well in Phase III for asthma, a related field that highlighted its potential for COPD. But AstraZeneca has a history of polishing up fragments of data on patient subsets when faced with a setback. The company chose to assign a peak sales value to its drugs when Pfizer came calling with a takeover bid, and now may be forced to explain to investors at some point why some of these spotlighted blockbusters aren't living up to high expectations.

That day, though, won't be today. AstraZeneca pushed benralizumab into Phase III over the summer, and it is still voicing enthusiasm for the IL-5 antibody.

"COPD is a highly heterogeneous disease and we are working to better understand patient subtypes, identify potential biomarkers and tailor therapies to achieve the best outcomes for patients," said Bing Yao,the head of MedImmune's respiratory, inflammation and autoimmunity innovative medicines unit. "Respiratory disease is a core therapeutic area for AstraZeneca and we are encouraged by these results indicating benralizumab's potential to help certain groups of patients. We look forward to the further development of this promising new biologic as we progress our Phase III programs in both COPD and severe asthma."

- here's the release