Schering-Plough had cause for celebration yesterday after the US Food and Drug Administration approved its once-daily asthma treatment, Asmanex Twisthaler (mometasone furoate dry powder inhaler).

Asmanex is specifically approved for the first-line maintenance treatment of asthma as preventative therapy in patients 12 years of age and older. S-P claims it is the only inhaled asthma controller therapy approved for once-daily initiation and management of asthma in patients previously treated with bronchodilators alone or inhaled corticosteroids. Clinical studies with Asmanex have shown substantial improvement in lung function, decreased use of rescue medication, decreased incidence of nighttime awakenings and significant improvements in daytime symptoms such as coughing and wheezing.

However, Industry reports question the product’s actual market potential, given that it was originally filed with the FDA back in 1998 and will have to compete with rival offerings that have been launched in the intervening years. Reuters suggests that Asmanex will no longer fulfill analysts’ expectations of annual sales in excess of $1 billion dollars, and instead believe the product will generate sales of around $350 million per year. Competing offerings include GlaxoSmithKline’s number one product, Seretide/Advair (salmeterol and fluticasone), which brought £2.5 billion in 2004 – up 19% [[11/02/05a]] – and AstraZeneca’s Symbicort (budesonide and formoterol), which saw 2004 sales increase by 32% to $797 million [[28/01/05b]].