Shares in SkyePharma have slipped this morning after the UK drug delivery specialist said that US approval for its asthma drug Flutiform will not happen for a couple of years at least.

The company said that it has held a previously-announced meeting with the US Food and Drug Administration which has confirmed that “additional clinical work will be required to provide more data on dosing” for Flutiform (fluticasone and formoterol). The news of extra trials comes as no surprise as the FDA told SkyePharma in June that “further clarification is required” concerning the treatment.

The London-headquartered company said it believes that “it is unlikely that Flutiform will, therefore, be approved in the USA before the second half of 2011”. Chief executive Ken Cunningham said that “we now have greater clarity from the FDA on its approach to our filing and we are working to address these issues as soon as possible”.

He added that the combo remains on track in Europe and Japan, “and we remain confident that, once approved and launched in its various markets, Flutiform will be a successful product for SkyePharma in terms of both revenues and cash flows." In Europe, partner Mundipharma is expected to file Flutiformby the first quarter of 2010.

The company's partner across the Atlantic, Abbott Laboratories, is responsible for paying for additional US clinical trials, and is entitled to recoup its costs out of up to 25% of any approval or post-approval milestones and royalties. News of the delay sent SkyePharma shares down 6.6% by 9.55 this morning.