GlaxoSmithKline announced that the US Food and Drug Administration (FDA) has issued a not approvable letter for the supplemental drug application for the 500/50 strength of Advair Diskus (fluticasone propionate and salmeterol inhalation powder) in the treatment of patients with chronic obstructive pulmonary disease (COPD).

The FDA questioned how Advair 500/50 compared to the currently approved 250/50 strength in order to allow for appropriate dosing recommendations. GSK will be meeting with FDA to discuss this request in more detail and determine next steps, including discussion of data GSK has recently generated on the reduction of exacerbations with the Advair 250/50 strength.

"We are very surprised and disappointed by this FDA decision particularly given the outcome of the FDA advisory committee meeting earlier this year," said Katharine Knobil, MD, vice-president of respiratory clinical development for COPD at GSK. "The advisory committee voted unanimously that Advair 500/50 demonstrated a significant reduction in the risk of exacerbations. We believe in the strength of the data; this application is based on the results of the largest COPD study conducted in more than 6,000 patients over three years. We are committed to working with the FDA to address any questions they have and to pursue a way forward."

Advair 250/50 is currently indicated for the maintenance treatment of airflow obstruction in patients with COPD associated with chronic bronchitis. Advair does not replace fast-acting inhalers to treat sudden symptoms. Lower respiratory tract infections, including pneumonia, have been reported following the inhaled administration of corticosteroids, including fluticasone propionate and Advair Diskus.