Patients with poorly controlled asthma are a step closer to a new treatment option after Phase III data showed that Boehringer Ingelheim's lung drug tiotropium significantly reduced exacerbations and improved both lung function and quality of life.

Results from the PrimoTinA-asthma Phase III clinical programme revealed that tiotropium, delivered by the Respimat SoftMist inhaler, cut the risk of severe asthma exacerbation by 21% in patients who remain symptomatic despite receiving treatment for the disease.

The risk of any asthma exacerbation was also slashed by 31%.

"While we were anticipating improvements in lung function when adding tiotropium to usual care, the significant reduction in the risk of exacerbations came as a surprise – especially given that all patients were already receiving optimal maintenance treatment as defined by the GINA guidelines," commented study author Professor Huib Kerstjens of the University Medical Centre, Groningen.

The German drugmaker said there were also significant improvements in lung function, asthma control and asthma related quality of life, lending further weight to the case for its use in controlling the disease.

The need for new and effective asthma treatments is great because a significant proportion of patients remain symptomatic and may experience asthma exacerbations despite current therapies, the firm said.

Tiotropium is a long-acting inhaled anticholinergic bronchodilator that works by opening narrowed airways and helping to keep them open for 24 hours.

Blockbuster for COPD

Approved as a treatment for chronic obstructive pulmonary disease under the tradename Spiriva and co-marketed by drug giant Pfizer, the product pulled in sales of more than 3 billion euros last year, and an extra indication in asthma could significantly boost its turnover.

However, there remain concerns over the drug's risk in patients with heart disease. Last year, an analysis published by the British Medical Journal found that the use of Spiriva delivered in a mist form (via Respimat) was linked with a 52% increase in the risk of death. 

BI said it did "not agree with the authors’ conclusion that there is an increased mortality risk for Spiriva Respimat in COPD,” and that its risks and benefits were included in its label, Bloomberg reported at the time.

Nevertheless, the company is currently conducting a huge study, with more 17,000 patients, comparing Spiriva Respimat with the Spiriva Handihaler (powder form) to confirm both the efficacy and safety of the product, data from which are now reportedly expected in 2014.