Campaigners for flibanserin claim that 26 drugs have been FDA-approved for male sexual dysfunction and none for women.
In the 1990s, Pfizer began development on a drug called UK-92480, intended as a treatment for angina and high blood pressure. The drug worked by inhibiting an enzyme that causes the inside of blood vessels to contract. The theory was, if this process was disrupted, then the cells would relax, improving blood flow and relieving blood pressure.
However, UK-92480 did not work quite as intended. Trials found that the drug amplified the effect of nitrates - the standard treatment for angina - causing blood pressure to fall too low. Side effects of UK-92480 included muscle aches and - amongst male volunteers - increased erections for several days following the initial dose.
Faced with the reality that UK-92480 was not a viable angina treatment, Pfizer took an interest instead in its unintended effects. As a treatment for erectile dysfunction, UK-92480 was much more effective than a placebo. In 1998, the drug was approved for this use by the Food and Drug Administration (FDA), and it was rechristened Viagra.
In the 17 years since, drugs acting as variations on Viagra's mechanism have also made it to market as erectile dysfunction treatments. What has been conspicuous in its absence, however, has been "a Viagra for women."
Following the FDA's second decision not to approve flibanserin, in fall 2014, two well-funded media campaigns - Even The Score and Women Deserve - set about engaging women's groups, starting up petitions and lobbying policymakers on the issue. A mantra of these campaigns is the figure "26-0."
What 26-0 relates to is a claim made by Cindy Whitehead, the CEO of Sprout Pharmaceuticals (who now own flibanserin) - and reportedly the creative mind behind Even The Score and Women Deserve - that 26 drugs have been FDA-approved for male sexual dysfunction and none for women.
Watch Women Deserve's Viagra parody video below:
"Women have waited long enough," write Even The Score, of their pro-flibanserin petition, which is reported to have attracted more than 40,000 signatures. "In 2015, gender equality should be the standard when it comes to access to treatments for sexual dysfunction."
Accusations of data manipulation
However, critics have claimed that Even The Score's campaign is built on misinformation. The 26 products for male sexual dysfunction are actually different regional brands of the four main erectile dysfunction treatments, which themselves adhere to a similar mechanism.
Do 43% of American women really have a sexual dysfunction?
Another statistic wielded by the campaigns - the claim that 43% of American women have a sexual dysfunction - has also come under fire. The figure is drawn from a contentious 1994 survey that gave its female respondents the option of answering yes or no to whether they had any sort of sexual problem, but the survey did not collect any data on what the nature of the problem was - even the senior author of that study has reportedly claimed the statistic is misused.
A claim published on womendeserve.org that "a biological lack of desire to have sex negatively impacts 1 in 10 American women" was questioned in a high-profile LA Times piece by Kinsey Institute research fellow and sexologist Prof. Ellen Laan, and Leonore Tiefer, professor of psychiatry at NYU School of Medicine and founder of the New View Campaign.
"No diagnostic test has identified any biological cause - brain, hormone, genital blood flow - for most women's sexual problems," the pair wrote. Rather, they claim that low sexual desire in women more likely reflects a difference in desire between the two partners.
"It is unethical and unscientific to attribute a couple's discrepancy in desire to the woman's biological deficit," they continue, pointing out that studies have shown women's response to both test medications and placebo drugs is high. "These repeated findings do not support the 'unmet medical need' theory."
What Laan and Tiefer's article and the New View Campaign emphasize is that Viagra and flibanserin are false equivalents. Viagra treats erectile dysfunction, while Sprout claim that flibanserin is an antidote for low sexual desire in women. Viagra does not increase male libido; rather it acts on the mechanism that allows an erection to happen.
What flibanserin is concerned with - boosting sexual desire - is more amorphous and complex. New View even argue that male and female sexual dysfunctions are also not equivalents, so a female Viagra would therefore not be appropriate for women.
'Hypoactive sexual desire disorder' and the DSM
The New View Campaign take issue with the current sexual dysfunction classification implemented by the American Psychiatric Association (APA) in its 1980 edition of the Diagnostic and Statistical Manual of Disorders (DSM), which envisions male and sexual "dysfunction" as equivalents across four categories: sexual desire disorders, sexual arousal disorders, orgasmic disorders and sexual pain disorders.
The illness that flibanserin is purported to treat - hypoactive sexual desire disorder - was removed from the DSM in 2013.
They consider that this has led to a reductive, mechanistic perception of how female sexuality works in relation to male sexuality. They argue that women's sexual problems are less physiological and genital-focused than men's, that "women generally do not separate 'desire' from 'arousal,' women care less about physical than subjective arousal, and women's sexual complaints frequently focus on 'difficulties' that are absent from the DSM."
"The DSM takes an exclusively individual approach to sex, and assumes that if the sexual parts work, there is no problem; and if the parts don't work, there is a problem," summarize the campaigners.
Instead, the campaigners say, it has fostered a commercial drive to produce "a female Viagra" - a pharma sensation that will repeat the massive success of that drug for a new audience, regardless of whether pharmacology is the correct intervention, or to what extent there is a problem that requires treatment.
In fact, the specific illness that Sprout argue flibanserin treats - hypoactive sexual desire disorder (HSDD) - was removed from the DSM in 2013.Medical News Today spoke to Thea Cacchioni, an assistant professor of women's studies at the University of Victoria in British Columbia, who testified against flibanserin the first time it was unsuccessfully submitted for FDA approval in 2010. She asserted bluntly of flibanserin's position in the modern pharmaceutical landscape: "there is no recognized illness it treats."
"There are many problems with the HSDD disorder, as I mentioned in the hearing," Cacchioni told us, "how could we ever come up with a baseline level of normal desire? Norms of desire vary from era to era and culture to culture. Also, research shows that most desire problems are caused by external factors - interpersonal, relationship issues, social judgements and pressures related to especially women's sexuality, feelings of inadequacy, work stress, etc."
As fascinating as the cases for and against the idea of a pharmaceutical intervention for female sexual dysfunction are, the issues that Cacchioni and others expressed the greatest concern about when testifying in 2010 were much less philosophical and more to do with hard data.
Does flibanserin work and is it safe?
Firstly, does flibanserin work? The evidence presented to the FDA was perceived as being somewhat subjective - clinical trial found that it produced an additional 0.7 "sexually satisfying events" per month.
Secondly, is flibanserin safe? The drug's clinical trials saw a 14% drop-out rate due to adverse effects. The full data were not reported on what these adverse effects were, but what is known is that women taking flibanserin had 10 times the risk of dizziness and four times the risk of sleepiness compared with a control group.
"These may sound minor," explained Cacchioni, "but since this drug was tested on a highly select group of women, there is concern over what would happen if a wide population of women take this drug on a daily basis? What drug interactions will we see? Is there a risk of impaired driving?"
Whether or not Sprout will be "third-time lucky" in today's quest for FDA approval hinges on new evidence the agency has requested the pharma company submit regarding the possibility of impaired driving.
Cacchioni, who has also written a book on the issue - "Big Pharma, Women, and the Labour of Love," out in August - is not convinced the new data will be enough to swing an FDA approval, despite the intense media attention and public interest the case has received.
"Clearly, Sprout is hiding something," she told us, "since they have followed up on this important request by submitting evidence from only 25 volunteer participants, 23 of whom are men! They claim they could not find any more women who were moderate drinkers."
"I have faith that the FDA will stand its ground and not approve flibanserin. If they do, they are sending a very dangerous message - that drug companies and their marketing machines can pressure them into approving drugs that are unsafe and ineffective."
In a recent blog for Science 2.0, Josh Bloom - director of chemical and pharmaceutical sciences at The American Council on Science and Health in New York City, NY - says that while the statistical significance of improvement in sexual arousal was excellent in flibanserin's trial, a "statistically significant improvement in a study is not the same as a significant clinical improvement." He elaborates that, in terms of evidence of improvement, "there are no 10-fold differences as was the case with adverse effects. The differences in efficacy are roughly in the 1.5-fold range."
"Which brings up the exact same question that the FDA is faced with every time it decides whether a drug gets approved or not," Bloom writes. "Do the benefits outweigh the risks? The FDA has already said no three times. This should have been over with long ago."
So why are Sprout persisting with flibanserin? The company was founded in 2011 by Cindy and Robert Whitehead, who raised $50 million to save the drug from the scrapheap, after it was first declined by the FDA.
The drug's creators, the German pharma company Boehringer Ingelheim, gave up on flibanserin. Like Viagra, the drug was not developed to be a treatment for sexual dysfunction - it was a prospective antidepressant. Antidepressants that increase serotonin have a side effect of dampening sexual response. However, flibanserin seemed to improve it - possibly by raising the levels of the neurotransmitters dopamine and norepinephrine while decreasing serotonin.
Flibanserin as sexual equality battlefield
Sprout, via the Even The Score and Women Deserve campaigns - coordinated with the largely big pharma-funded International Society for the Study of Women's Sexual Health - have painted the battle to get flibanserin to market as an ideological struggle against a patriarchal and discriminatory regulatory system that is not fit for meeting the health needs of women.
Despite support from the National Council of Women's Organizations, the Black Women's Health Imperative, Jewish Women International and the Association of Reproductive Health Professionals, the emotive pro-flibanserin campaign has not washed with everyone. Ellen Laan and Leonore Tiefer were scathing in their dismissal of its rhetoric:
"As professional sexologists and advocates of women's sexual rights, we were horrified by the campaigns' use and abuse of the language of equality to pressure the FDA to approve a potential billion-dollar blockbuster 'pink Viagra.' The only two drugs for women's sexual dysfunctions that have come to the FDA in the 16 years since Viagra was approved were rejected. [...] The drugs for women didn't work and were unsafe. Not approving them isn't sexism, it's proper regulation."
Cacchioni concurs, suggesting that perhaps the reason why no drugs have been shown to be safe or effective "is that most sexual problems are related to interpersonal, psychological, and social factors, including the social construction of sexual norms."
"Perhaps," she concludes, "we are putting too much pressure on ourselves to realize a level of desire that is not realistic for everyone across the life course."
With several FDA rejections and $50 million of investment already behind them, it will be interesting to see how Sprout and Even The Score will continue to frame the debate for "a female Viagra" if approval today is not forthcoming.
If it does succeed in winning approval, however, the Whiteheads could have a blockbuster drug on their hands with a market value of billions.
'Female viagra' August 2015 update
The first drug to treat sexual dysfunction in premenopausal women - dubbed the "female Viagra" - has since received approval from the US Food and Drug Administration.