GlaxoSmithKline says it has resubmitted its New Drug Application to regulators in the USA for Solzira, the restless legs syndrome treatment it has developed with Xenoport.

The firms withdrew their NDA for Solzira (gabapentin enacarbil) extended-release tablets in November after the US Food and Drug Administration requested that the data in a single study be reformatted. In addition, GSK has conducted a review of other clinical studies taking this input into account and noted that the withdrawal was not related to the content of the filing.

Solzira is a new chemical entity designed to improve upon the pharmacokinetics of gabapentin, the active ingredient in Pfizer’s blockbuster epilepsy drug Neurontin, which is off-patent. GSK said that the extended-release formulation, which has also been developed along with Japan’s Astellas Pharma, “takes advantage of high-capacity transport mechanisms in the gastrointestinal tract to improve absorption”.

Meantime, GSK chief executive Andrew Witty has told the Wall Street Journal that the company is cutting back on its advertising campaigns on US television.

In an interview with the newspaper, Mr Witty declined to say by how much the company will reduce its expenditure on advertising, an area that companies have been criticised for spending heavily on. However he added that the concept of consumer advertising is still valid in many cases, for instance in promoting drugs for sexually transmitted diseases.

The WSJ claimed that GSK spent $279.1 million on consumer advertising in the USA in the first half of 2008, second behind Pfizer’s expenditure of $462.5 million.