GlaxoSmithKline said yesterday its combination asthma drug Seretide had become the first drug to reduce the risk of death in patients with chronic obstructive pulmonary disease (COPD).

The results of the 6,100-patient TORCH study reveal that Seretide (salmeterol and fluticasone), sold as Advair in the USA, reduced all-cause mortality by 17% in COPD patients over a three-year period compared to a placebo, although this narrowly missed achieving statistical significance.

The drug also reduced the rate of COPD exacerbations by 25% and improved patients’ quality of life, both of which were statistically significant results, said GSK.

“This is the first study that demonstrates a benefit of drug therapy on survival in COPD,” said GSK, noting that to date that apart from surgery, the only other interventions to reduce the death rate in these patients have been stopping smoking and long-term oxygen therapy for patients with low blood oxygen.

The formulation used in the study included 50mcg salmeterol and 500mcg of fluticasone, which is approved for COPD in Europe and other world markets, but not in the USA.

GSK said it would work with regulatory authorities to incorporate the new data into prescribing information for the product, although analysts said that the lack of statistical significance for the mortality result made it hard to predict how those negotiations would go.

Seretide/Advair is GSK’s top-selling product, adding £3 billion ($5.2bn)to the company’s coffers last year, a rise of 22%.

However, it fell under something of a shadow last November after the US Food and Drug Administration (FDA) said it planned to restrict its use to patients who fail to respond to other treatments after an increase in asthma-related deaths was seen in a clinical trial.

Analysts have suggested that the label change in asthma will have little impact on Seretide’s growth, and ahead of the publication of the top-line data from TORCH said a good result in the study could boost peak sales of the drug, with forecasts coming in at £5 billion to nearly £7 billion by the end of the decade.