Ann Arbor biotech company QuatRx Pharmaceuticals is preparing to file a new drug application with the U.S. Food and Drug Administration after completing the final clinical trial for its top drug candidate.

Approval of QuatRx's post-menopausal sex drug would mark a significant accomplishment matched only by a few drug companies nationwide every year. It could also mean dozens or hundreds of new jobs for the Ann Arbor region if the company decided to market the drug itself.

QuatRx announced this morning that its drug candidate, Ophena, had successfully completed Phase 3 efficacy and safety studies. That's the final stage in the drug development process before a company can file a new drug application with the FDA.

Ophena would treat a condition called post-menopausal vulvovaginal atrophy, which causes dryness or irritation that can make sexual activity painful. The drug could also be used by women who experience such symptoms but aren't sexually active.

QuatRx officials could not be immediately reached for comment this morning. The company is likely to file its FDA application by early 2010.

“With the completion of our second pivotal Phase 3 study, we believe we have now fully confirmed the efficacy of Ophena according to the criteria established by FDA under the applicable guidance for this indication," QuatRx CEO Robert L. Zerbe said in a statement. "Based on this, we are working aggressively to move forward with our NDA submission and to bring this promising new treatment option to the millions of women affected by vaginal atrophy who want an alternative to estrogen therapy.”

Experts believe some 45 percent to 75 percent of post-menopausal women experience "chronic symptoms of vaginal atrophy," Ophena officials said.

The company has been hesitant to offer a specific estimate of the drug's potential market. But Viagra, which treats sexual dysfunction in men, boasts a market north of $1.8 billion.

To market a drug like Ophena, QuatRx could choose to sign a licensing deal with a major pharmaceutical company that would sell the drug itself. But it could also opt to market the drug itself, which would mean the company would have to hire sales workers to handle the task.

FDA approval for Ophena is far from guaranteed, however. Many drug companies, even major pharmaceutical companies, have a hard time convincing the FDA that their drug candidates are fit for the market.

Still, just getting past Phase 3 is a monumental moment for QuatRx.

"These findings provide substantial additional evidence indicating the potential of Ophena to be a first-in-class non-estrogen drug for the treatment of vaginal atrophy," Zerbe said in the release.

Contact AnnArbor.com's Nathan Bomey at nathanbomey@annarbor.com or (734) 623-2587 or follow him on Twitter.