LINCOLNSHIRE, Ill. ( TheStreet) -- BioSante Pharmaceuticals ( BPAX) will tell us soon whether or not its testosterone gel improves the sex lives of certain women.

A scheduled presentation Wednesday by BioSante executives at an investor conference was cancelled this morning. No reason was provided but it's not a stretch to assume BioSante has results in hand from two phase III efficacy studies of Libigel.

BioSante is likely to announce the results of the Libigel studies this afternoon or tomorrow morning. That's an educated guess given that data were expected to be ready mid-December.

Here's what you need to know about Libigel as we wait for the data to be announced:

What is Libigel?

Libigel is a low-dose testosterone gel, designed for daily use by post-menopausal women to improve their sex drive. These women -- in menopause due to surgery or for natural reasons -- suffer from female sexual dysfunction (FSD) or hypoactive sexual desire disorder (HSDD).

Libigel is female Viagra, right?

Not exactly. Pfizer's ( PFE - Get Report) Viagra works mechanistically by boosting blood flow in men "down there." Libigel is a hormone. How or why boosting testosterone blood levels improves female sex drive has not been entirely explained but large, previously published medical studies have backed up the effect.

To date, no testosterone product has been approved for this indication, which gives BioSante the opportunity -- or burden -- to be first.

Burden, why would selling a female Viagra be a burden?

The legitimacy of FSD and HSDD as real diseases is still up for debate. Some accuse drug companies of disease mongering -- making up the disorders to sell unnecessary drugs to women who aren't really "sick."

Selling Libigel, if it's ultimately approved, will also require a large marketing budget, including money for consumer advertising. BioSante doesn't have the money, talent or resources to handle the job on its own, so it's going to need a Big Pharma partner. To date, none have stepped up.

More than efficacy, the safety of therapies like Libigel is the real regulatory hurdle. BioSante will be announcing efficacy results from two phase III studies of Libigel now but a large cardiovascular safety study of the product is still underway and will not yield data until next year. BioSante can't see approval for Libigel unless the safety study comes back clean.

Describe the Libigel phase III studies.

Two phase III efficacy studies, nicknamed "Bloom" each enrolled 500 women aged 30-65, all of who are menopausal due to the surgical removal of their ovaries. The women are randomized to receive daily treatment with Libigel or a placebo gel for 24 weeks.

The goal of both studies is show that Libigel can improve sex drive compared to placebo using two different measures: An increase in the number of sexually satisfying events (SSEs) from baseline to weeks 21-24 and an increase in the Inventory of Sexual Events and Desire (ISED), a score of sexual desire.

In order for the Libigel studies to be positive, both co-primary endpoints must be met with statistically significance.

What are the odds that the Libigel studies work?

High. Investor sentiment definitely leans toward positive Libigel efficacy results. This isn't just guesswork. BioSante conducted randomized phase II study demonstrating a statistically significant, +3.4 increase in sexually satisfying events at three months for Libigel over placebo at the same dose being used in the phase III studies.

The phase III "Bloom"studies use the same dose of Libigel and are powered to be statistically positive if Libigel-treated women show an improvement of a single sexually satisfying event over placebo.

Also note that Procter & Gamble ( PG - Get Report) ran a series of successful clinical trials of Intrinsa, a testosterone patch (not a gel) for women with FSD and HSDD. The FDA rejected Intrinsa due to the concerns that testosterone therapy in post-menopausal women could raise heart-safety risks. It's these potential safety risks that forced BioSante to run its own large Libigel safety study to assuage FDA concerns.

What's the major risk with the phase III studies? The placebo effect in trials like these can be high, which may trip up Libigel's efficacy. The Libigel dose chosen by BioSante better be right on target. In the phase II study, lower and higher doses of Libigel also tested failed against placebo.

Any other stocks to be affected by BioSante's imminent release of the Libigel efficacy data?

Antares Pharma ( AIS) will receive a royalty on Libigel sales, if approved.

--Written by Adam Feuerstein in Boston.

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Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.