A turbulent week for GlaxoSmithKline has ended on yet another sour note with the news that US regulators will not fast-track the firm’s cervical cancer vaccine Cervarix, leaving Merck & Co’s Gardasil competition-free for a while longer.

The US Food and Drug Administration has declined to grant a priority review for Cervarix, which would have significantly accelerated the approval process for the vaccine and got it onto the all-important US market quicker. A drug is given a priority review if the treatment being evaluated is deemed by the FDA to address unmet medical need and offer a major improvement on current therapy.

Instead, Cervarix will go through a standard 10-month review, rather than six months if fast-tracked and GSK expects to get it to reach the US market sometime in 2008 rather than later this year. In Europe, the picture looks rosier, as the company is expected to get a positive recommendation for the vaccine from the European Medicines Agency's Committee for Medicinal Products for Human Use in the next month. Last week, the Therapeutic Goods Administration of Australia gave it the thumbs-up.

Analysts were not overly surprised by the FDA’s decision and Prudential Equity's Timothy Anderson said in a research note that it now appears likely that Merck's cervical cancer vaccine Gardasil will not have a competitor in the USA until the first quarter of 2008 at the earliest. Dresdner Kleinwort’s Ben Yeoh agreed that said while “there was a small chance” that a fast-track review would be granted, nevertheless “this is a slight negative for sentiment”.

Any further negative sentiment is the last thing GSK needs after the buffeting its share price has suffered since the study published in the New England Journal of Medicine last week that indicated that the diabetes blockbuster Avandia (rosiglitazone) increased the risk of heart attacks and death. The company has gone to great lengths to present evidence which indicates that the drug's safety is comparable to other therapies on the market and the letter sent to The Lancet a couple of days ago extolling the virtues of Avandia helped stem the decline the stock was being subjected to.

GSK will now be hoping to focus investors’ attention on its cancer therapies at the American Society of Clinical Oncology meeting, starting in Chicago later today. The company is making some 30 presentations and highlights are expected to include good news about recently-approved Tykerb/Tyverb (lapatinib) for breast cancer and its promising new angiogenesis inhibitor pazopanib.