Pfizer Inc. urged a U.S. panel to recommend approval of Fablyn, an experimental treatment for women with weak bones, saying increases in deaths during clinical trials weren't caused by the drug.

The once-a-day tablet's ability to prevent broken bones outweighs the risk of side effects seen in studies, Pfizer told outside advisers to the Food and Drug Administration meeting today in Rockville, Maryland. The agency is asking the panel whether the drug should be approved for the 10 million Americans living with osteoporosis, mostly older women.

An overall increase in deaths during clinical trials wasn't statistically significant, according to Pfizer. A low dose of Fablyn was linked to more deaths from cancer and stroke in an FDA staff review released last week, though Pfizer said the drug wasn't likely to be the cause. Pfizer is seeking approval to sell a higher, 0.5-milligram dose that wasn't linked to a statistically significant increase in mortality, according to the company.

"It is generally safe and well-tolerated," said Roisin Armstrong, senior director of Pfizer's Fablyn development team, during the drugmaker's presentation.

Pfizer, the world's biggest drugmaker, needs new products to offset generic competition by 2011 to its cholesterol pill Lipitor, the world's top-selling medicine with $12.7 billion in sales last year. Analysts have said Fablyn may have as much as $500 million in annual sales if approved.

The FDA should act on the companies' new-drug application by October, based on the December filing disclosed in Pfizer's annual report. The agency usually follows the recommendations of its advisers, though it isn't required to do so.

Pfizer, of New York, would pay San Diego-based Ligand Pharmaceuticals Inc. a lump sum upon approval and payments based on sales. Ligand's technology was used during discovery of the drug.

Pfizer rose 49 cents, or 2.7 percent, to $19 at 11:28 a.m. in New York Stock Exchange composite trading. Ligand rose 2 cents to $3.23 on the Nasdaq Stock Market.

Fablyn, or lasofoxifene tartrate, was rejected by the FDA in September 2005 as a medicine to prevent osteoporosis because the agency had concerns that it may cause cancer in the lining of the uterus, according to Pfizer. The drug also was rejected in January 2006 as a treatment for vaginal atrophy. The companies decided to try again for approval after re-examining safety data.

There were no increases in uterine cancer in the most recent study, called Pearl, although at the lower dose of 0.25 milligrams there was a rise in combined fatalities from all forms of cancer. The previously unreported study followed more than 8,000 patients for five years.

Patients taking a 0.5-milligram dose of Fablyn were 41 percent less likely to have new or worsening vertebrae fractures compared with patients taking a dummy pill, the FDA review found.

Demand for new treatments for osteoporosis has increased as the U.S. population ages. Fablyn works similarly to Eli Lilly & Co.'s Evista. The drug would also compete with Novartis AG's Reclast, Roche Holding AG's Boniva, Procter & Gamble Co.'s Actonel and Merck & Co.'s Fosamax, the market leader before it went generic in February. Amgen Inc.'s experimental denosumab has also been shown to strengthen bones and reduce fractures.