AstraZeneca's assault on GlaxoSmithKline’s position as the company selling the most-prescribed combination respiratory drug received a boost yesterday when it presented clinical data claiming Symbicort is superior to GSK’s Advair/Seretide for treating asthma and chronic obstructive pulmonary disease.

One of the studies found that a new flexible dosing regimen for Symbicort (budesonide/formoterol) – dubbed SMART - was more effective than Advair (fluticasone/salmeterol) in reducing asthma exacerbations.

The second study showed that Symbicort provided a faster onset of relief for symptoms of breathlessness in COPD sufferers than GSK’s drug. Both were presented at the European Respiratory Society annual congress in Munich, Germany.

The asthma study (COMPASS) found that in patients with poor control of asthma on moderate doses for inhaled steroids, Symbicort SMART achieved a 39% reduction in the number of exacerbations compared to a fixed dose of Advair/Seretide, without increasing the overall amount of corticosteroid used by patients.

The SMART dosing allows patients to increase the dose of Symbicort when their asthma is bad, helping them relieve symptoms more effectively and reducing the severity of attacks.

Meanwhile, the COPD study presented at the ERS meeting showed that Symbicort had an onset of action similar to salbutamol and better than Seretide/Advair in achieving an improvement in airway dilatation five minutes after inhalation.

"Speed of onset is as important in COPD as it is in asthma, especially in the morning when patients often require a rapid onset of bronchodilatory effect,” commented Prof Martyn Partridge of Imperial College London.

The study used a formulation of Symbicort based on a pressurised metered dose inhaler that is not yet cleared for marketing in the European Union.

Symbicort is firmly planted in second place in the combination respiratory drug market, with first-half sales of $585 million, compared to the $2.93 billion reported by GSK for Advair in the same period. But AstraZeneca can now compete on a level playing field with GSK, having recently won approval for Symbicort drug in the USA which accounts for a sizeable chunk of Advair revenues.