* FDA pushes back vandetanib decision 3 months to April 7
* Delay is latest in run of pipeline setbacks
* Vandetanib seen as niche product; shares down 0.7 percent (Adds detail on medullary thyroid cancer, background)
By Ben Hirschler
LONDON, Jan 7 (Reuters) - AstraZeneca's new thyroid cancer pill vandetanib faces a three-month delay in the United States after regulators extended the time needed to complete a review of the medicine.
The Food and Drug Administration (FDA) had been due to give its verdict by Jan. 7, but the company said on Friday the deadline had been pushed back to April 7 after it submitted a risk evaluation and mitigation strategy to the agency as requested.
Although vandetanib is not expected by analysts to become a top seller, the delay is a fresh setback for the Anglo-Swedish group, which has had a series of pipeline disappointments in recent weeks.
U.S. advisers to FDA last month urged further study of vandetanib after the drug reaches the market. The committee of outside specialists was not asked to vote specifically on whether to recommend approval, but most panel members said the drug offered benefits.
Vandetanib was once seen as a potential $1 billion-plus blockbuster for AstraZeneca, but suffered a major setback after failing to extend survival in patients with lung cancer.
The drug is now targeted at the niche market of treating patients with non-operable advanced medullary thyroid cancer (MTC), which accounts for about 4 percent of thyroid cancers.
While there is no treatment for MTC apart from surgery, the limited number of patients involved means analyst forecasts for vandetanib sales are a modest $188 million in 2015, according to Thomson Reuters Pharma consensus estimates.
AstraZeneca shares were 0.7 percent lower by 1515 GMT, underperforming a flat European healthcare sector, following news of the new FDA review date.
The London-based drugmaker, which is heading into a period of extensive patent expiries, has suffered a number of setbacks recently, including a delay in U.S. approval of blood thinner Brilinta, its most important new drug.
It has also dropped plans to develop motavizumab for the prevention of serious lung disease in infants and ditched Certriad, a combination heart drug it was working on with Abbott Laboratories.
(Editing by David Hulmes)