US health regulators have delayed their decision on whether to approve Sanofi-Aventis' highly anticipated weight loss drug, Acomplia.

The French company said the new action date by the US Food and Drug Administration for Acomplia, also known by the chemical name rimonabant, would now be July 27.

The company had initially expected to be able to begin selling the drug in the United States in the second quarter of 2006. But the FDA asked for additional information last year, pushing the expected approval decision date on the once daily pill to April of 2007 prior to last Monday's announcement of a further delay, Reuters report said.

The U.S. Food and Drug Administration removed the requirement that Amylin's Byetta be refrigerated, but analysts are split on whether this will lead to a boost in sales of the diabetes medication.

The FDA's decision means the Byetta pen, which still has to be refrigerated until first use, can now be kept at room temperature after that.

Sanofi aventis' Acomplia -- if it wins FDA approval -- could also impact Byetta. Sanofi is seeking an obesity indication for the drug, but if it gets approved for type 2 diabetes, it could steal some share from Byetta because it too offers the advantage of weight loss.

A lingering question, however, is Acomplia's association with depressed mood in some patients, Osborne said. "So we'll see how that plays out once it's on the market," he added.

Sanofi said last week the FDA pushed back its timeframe for making a decision on Acomplia from April 26 to July 27. The company did not divulge the reasons for the delay. Acomplia, which has been launched in 12 countries so far, generated 31 million euros in sales last year.