AstraZeneca will take a financial hit after announcing that it has discontinued development of the infant lung drug motavizumab for the prevention of serious respiratory syncytial virus disease.

The Anglo-Swedish drugmaker is taking a $445 million impairment charge in the fourth quarter and revealed that it has requested withdrawal of the Biological License Application pending at the US Food and Drug Administration in the aforementioned indication. The news is not terribly surprising seeing as how the agency issued a second complete response letter on the monoclonal antibody in September and requested evidence from an additional clinical trial "that supports a satisfactory risk/benefit profile in the population(s) for which the prophylaxis indication is being requested".

In June, the FDA’s Antiviral Drugs Advisory Committee voted 14 to 3 to recommend that motavizumab, developed by AstraZeneca's MedImmune biologics unit, should not be approved, claiming that the data provided merely shows that motavizumab is only as effective in reducing RSV hospitalisations as the company’s older treatment Synagis (palivizumab). The latter treatment, which is expected to lose patent protection in 2015, had sales last year of around $1.1 billion in 2009.

AstraZeneca still has some faith in the drug and noted that motavizumab "remains in development for other RSV treatment". The firm added that the charge will not affect its earnings per share guidance for the year of $6.50-$6.65.