The US Food and Drug Administration has agreed to review GlaxoSmithKline’s New Drug Application for its investigational antibacterial retapamulin, a member of a new group of antibiotics that is being developed as a topical treatment for uncomplicated skin and skin structure infections due to susceptible strains of Staphylococcus aureus and Streptococcus pyogenes.

The UK drugmaker submitted its application - based on Phase III clinical trial data involving more than 712 patients in the USA - to the FDA in November 2005, and is expecting to gain the seal of approval to market the product later this year.

Laboratory studies have demonstrated that the agent can provide a highly-effective weapon against the key pathogens responsible for skin and skin structure infections and, importantly, retapamulin has shown no target-specific cross-resistance to other established classes of antibiotics in vitro, the firm says.

This is significant, as the widespread use of antibiotics has fuelled the spread of antibiotic resistance, costing the US between $4 billion and $5 billion each year and creating an urgent need for antibacterials with no known cross-resistance.

Meanwhile, GSK also reported that it has started a late-stage trial of its investigational drug, eltrombopag, assessing the agent as a once-daily, orally-administered option for patients with previously-treated idiopathic thrombocytopaenic purpura, an autoimmune disorder characterised by low platelet count.

According to industry experts, eltrombopag has the potential to become one of the company’s key growth drivers, particularly as there are no effective treatments for low platelet count on the market. The condition can lead to all sorts of complications, such as interfering with the action of other drugs. Analysts have targeted peak sales in the £3-£5 billion range if it makes it to market.