The Desire For Desire: On-Demand Female Sex Drive Drug Approved

He pops his little blue pill to treat erectile dysfunction. She injects her thigh with the antidote for low desire. And soon it's off to bed, with some help from modern medicine.

That's the scenario that came to mind with the news that a new drug aimed at boosting sex drive in women troubled by low levels of desire — a condition called hypoactive sexual desire disorder — has just been approved by the Food and Drug Administration.

If the idea of a drug to fan female sexual desire sounds familiar, that's because the "little pink pill" was thoroughly debated back in 2015, when a company called Sprout launched an everyday pill called Addyi. (The debate topic could be summarized as "Female Sexuality: Is is too complex to be treated with a drug?")

That pill has not done well, STAT reports.  A study found its effects underwhelming, and it didn't help that patients were not supposed to consume alcohol.

But there are significant differences between Addyi and Vyleesi, particularly that Vyleesi is injected before sex rather than taken every day. Could this attempt at a female desire drug turn out differently?

I spoke with Dr. Julie Krop, chief medical officer of AMAG Pharmaceuticals, the Waltham, Massachusetts-based maker of Vyleesi. Here are lightly edited excerpts of our conversation.

So what is this new drug, and what can it mean for women?

HSDD — hypoactive sexual desire disorder --  which basically means low sexual desire associated with distress — is a really important condition that one in 10 premenopausal women suffer from. They have little desire, associated with distress, and there's no other known cause — they're not taking a medication that can cause changes in desire, they're not depressed, and they're not in a bad relationship.

This is a condition that is largely unrecognized by women as well as by physicians, and partly that's because there just haven't been good treatments. It's similar to depression, which was stigmatized many years ago before there were good treatment options.

What's really exciting about Vyleesi is that it's an on-demand treatment. Women don't need to be taking a medication all the time. Being able to take a medication that is only as needed, and not be exposed unnecessarily to a drug when they don't need it, is a really strong step forward for women.

And what about the pushback the last time a pill for female desire came out? Is this different? 

This is an important moment in time in terms of thinking about empowering women to think about sexuality in their own way. I think it's a good time for us to be raising this type of awareness.

Previously, people sort of thought: This is not a real condition, this is something that pharmaceutical companies have made up. What's really amazing to me is speaking to women suffering from this condition. Hearing their stories and the significant impact it had on their lives, it's really just mind-boggling to me that this has been even questioned as a real condition.

There are also MRI as well as CT and PET scan data that shows that when women who suffer from this condition are given erotic material, they have different activation in the areas of sexual function than women who don't. So it's a real physiologic condition that women are suffering from.

And the argument that it's medicalizing normal female experience?

We're not trying to say that sexuality is not complex. There are some psychological components and then there are physiologic components. We're focusing on the physiologic causes, and they're related to an imbalance in the brain in either excitatory or inhibitory pathways that are associated with sexual desire.

When you don't want to have sexual desire — at work, for instance — you need those inhibitory signaling pathways. But when you want to have sexual desire, you need those stimulatory pathways as well. When there is an imbalance, you end up with issues of having sexual desire when you want it. So what we're trying to do is restore that balance.

All the women who have HSDD had normal sexual desire at one time, and we're trying to restore that. We're not trying to create a different state of sexual desire than already existed in these patients. Each patient has a different set point, if you will, for sexual desire, and we're trying to restore that so they're not distressed anymore.

In clinical trials, it sounds like the effects were significant but relatively modest, right?

In order to diagnose, and in order to to recognize effectiveness, you have to look at interviews, questions patients are asked. There's no blood test, there's no CT scan. We use a variety of different psychological tools to be able to evaluate them. And the differences we see in those responses between active and placebo, which we refer to as effect sizes, were very similar to drugs that are used to treat depression.

So these effects are real. They're impactful in women's lives. And we're not trying to make people have high desire. People don't want to have too much desire, and people don't want have too little desire. They just want to have something in the middle. So we're trying to restore that set point, and that doesn't require large changes in magnitude.

Could you compare Vyleesi to Viagra?

There are some similarities and some big differences. They're both targeted at sexual disorders and they're both taken as needed. That's kind of where the similarities end, because erectile dysfunction is really a disorder of plumbing, if you will — the issue is having a physiologic erection — and the issue with HSDD is really more one of wiring and related to desire.

And how is Vyleesi different from the previous drug, Addyi?

Addyi is very different in the sense that it is an oral medication that's taken daily, and like an antidepressant, it typically takes eight to 12 weeks in order to have its maximum benefit. Vyleesi is  given on an as-needed basis with rapid onset of action. It's given as an injection — it's a peptide delivered by a small, pen-like, self-administered auto-injector. It's very easy to use; it's given either into the abdomen or into the thigh. You don't see the needle, it's very small, and 90% of patients in our studies reported it was very easy to use.

How quickly does it act? 

We tell patients to take it at least 45 minutes prior to desired sexual activity. Women in our clinical trials had a broad duration of action; some women took it in the afternoon anticipating activity in the evening. When we asked a subset of women in the clinical trial how long it lasted — it's hard to describe when desire ends. So we don't really know exactly how long it lasts, but we know some women say it lasted up to 24 hours. It just depends on the person.

And side effects? 

There are always adverse events associated with any medication. With Vyleesi, nausea, headache and flushing were the three most common adverse events. There were small transient elevations in blood pressure — we had to go back and do some additional work for the FDA — and that's where it's so important that the drug is given intermittently, so you're not being exposed to it for long periods of time, making the blood pressure issue much less relevant.

I think the most important thing is that when our six-month study ended, we allowed patients to continue on if they wanted, and over 80% of the patients who completed the trial decided to continue on to the full year. And so I think that's testimony to the benefit that they saw.

What if a woman whose desire is not distressingly low just wants to enhance her sex life?

As a company, we can't comment on anything off label for the product. In the clinical trials, we only treated patients with diagnosed HSDD.