UPDATE 2-Cadence says FDA delays painkiller review, shares fall

* Extended action date on the painkiller is Feb 12, 2010

* Co says now planning for a launch early in Q2, 2010

* Shares fall as much as 10 pct (Adds analyst comments, updates share movement)

Nov 13 (Reuters) - Drug developer Cadence Pharmaceuticals Inc (CADX.O) said the U.S. health regulators delayed the review date on its experimental painkiller by three months as certain additional data submitted by the company were considered a major amendment by the regulators.

Shares of the company were down as much as 10 percent at $8.61, before paring some of their losses to trade down 66 cents at $8.89 Friday morning on Nasdaq. About 570,000 shares changed hands in intra-day trade, more than twice the 50-day moving average volume of the stock.

"Most observers including ourselves had anticipated approval today. Hence the delay is a disappointment that may lead to a modest weakness in Cadence shares," Cowen and Co analyst Eric Schmidt said in a note.

"Nonetheless, we remain confident in Acetavance's approvability," he added.

The U.S. Food and Drug Administrator had earlier set an action date of Nov. 13 to decide on the drug acetaminophen, which had received a priority review status in July.

The priority review status typically means the agency would aim to complete its analysis of the application within six months, rather than within the standard 10-month review period.

The intravenous formulation of the pain reliever acetaminophen -- called Acetavance -- intends to treat acute pain and fever in adults and children.

The company was expecting to launch the drug early in the first quarter of 2010.

"We are now planning for a launch early in the second quarter of 2010 and continuing to move forward with all of our commercial readiness activities, including recruitment of our sales force," Chief Executive Ted Schroeder said in a statement.

Cowen's Schmidt, who has an "outperform" rating on the stock, said the company may not generate meaningful revenue until second half of 2010, but it is in a good financial condition.

As of Sept. 30, Cadence had cash, cash equivalents and short-term investments of $96.6 million. (Reporting by Krishnakali Sengupta in Bangalore; Editing by Pradeep Kurup)