The first 'female Viagra' is now available in the US - here's the story of how it got here

For the 34-employee company Sprout Pharmaceuticals, August marked the end of long and difficult battle that began when the company was first founded in 2011.

On August 18, the FDA gave a green light on the company's sole drug, flibanserin, which comes in the form of a little pink pill designed to spark sexual desire in women suffering from hypoactive sexual desire disorder (HSDD), where they have a chronically low desire to have sex.

And as of today, October 17, the drug is available for use in the US, with a prescription.

Business Insider spoke to Sprout Pharmaceuticals CEO Cindy Whitehead back when the drug was approved in August about the obstacles she faced to get this drug approved.

'For the women'

Since Viagra's approval in 1998, 24 drugs for male sexual dysfunction have been approved. Seventeen years later, women have their first to treat a similar condition.

"It's breaking up their marriages, it's really having them feel lesser," she said of women with hypoactive sexual desire disorder, the condition flibanserin is approved to treat. "I think the possibility of providing women access to a treatment really meant a lot to me."

The disparity from a scientific standpoint makes sense: Men get aroused when blood flows into their genitals. Women don't respond that easily. For women, researchers have to look at how to get the brain stimulated to increase sexual desire. But that's easier said than done.

Pharma giant Boehringer Ingleheim was the first to start developing flibanserin back in 2006, when a antidepressant drug actually increased libido instead of suppressing it, a common side effect for antidepressants.

The FDA rejected the pill in 2010 because it didn't show a significant change in women's labedo over placebos. That's when Whitehead swooped in and snatched it up.

She still thought the drug had the potential to be useful for women with HSDD.

"I saw this spectacular science that was going to be abandoned," Whitehead said. "And I thought it was going to be abandoned frankly because of a society unwilling to have a frank discussion about sex for women."

It took another rejection from the FDA in 2013 before Sprout could figure out how to meet with the agency's criteria and move the drug along toward approval, which it finally achieved last week.

"The FDA rules on science," she said. "And on Tuesday, they ruled on science."

A Valeant acquisition and the future

Just days after FDA approval, Valeant announced its plans to pick up Sprout for $1 billion, with future milestone payments that haven't been disclosed.

For Whitehead, an acquisition of her small Sprout team made a lot of sense.

"I think what this affords us is to do that in a way that we as a 34-person company wouldn't have otherwise been able to," she said. "I think that means ... affordable access for more women."

Whitehead said the acquisition's been in the works since the FDA panel ruled in favor of Addyi - the market name for flibanserin.

Now that the drug's approved, Whitehead said the next step is to focus on the short term goals of trying to get it on the market right way.

"I'd love to see this usher in a new era of interest in terms of investment and research for conditions like HSDD that uniquely impact women," she said.

Serious warnings

But there's still skepticism about how well the drug works, and at what cost. The drug carries some rather serious warnings. And it can cause severe side effects like a drop in blood pressure and fainting when consumed with alcohol.

What's more, although it was effective in trials in raising the number of times a woman has satisfying sex (which the scientists label "satisfying sexual episodes"), it didn't improve sexual desire - the very thing the drug was designed to do.

Women in the trials taking flibanserin saw an increase in the number of times they had satisfying sex from roughly 2.8 times a month to an average of 4.5 times a month, an increase of about 1.7 times.

Here's the problem: Women taking just a placebo in drug trials had more SSEs too, albeit by a slightly smaller number. Women taking a placebo saw their number of SSEs rise from an average of 2.7 per month to 3.7, an increase of 1.

In other words, controlling for the placebo effect, flibanserin's effectiveness amounted to roughly one extra episode of satisfying sex each month, David Kroll reports in Forbes. This was most likely one of the reasons the FDA has rejected pharma companies' petitions for it twice, according to FierceBiotech.

Yet the company making the drug, Sprout Pharmaceuticals, says this is enough of an increase to make it available to women.

And now the FDA appears to have agreed.

"The FDA strives to protect and advance the health of women, and we are committed to supporting the development of safe and effective treatments for female sexual dysfunction," said Janet Woodcock, M.D., director of the FDA's Center for Drug Evaluation and Research at the time of Addyi's approval.