Female Libido Drug Flibanserin Gets Mixed Reviews

Treatment shouldn’t be routinely prescribed until further results are in, authors say

Flibanserin (Addyi, Valeant Pharmaceuticals), a drug designed and approved to boost women’s sex drive, shouldn’t be recommended in treatment guidelines or routinely prescribed until future studies are conducted to prove its benefits in a wider range of women, according to a new study published in JAMA Internal Medicine. The quality of the information currently available is “very poor,” and additional details are needed for women with other health concerns, those who have undergone a hysterectomy, or those who are taking other medications, the authors say.

In August 2015, the FDA approved flibanserin as a treatment for hypoactive sexual desire disorder (HSDD) in premenopausal women. In the new study, researchers at Erasmus University Medical Center in Rotterdam, the Netherlands, conducted a systematic review and meta-analysis of randomized clinical trials that assessed the efficacy and safety of flibanserin in the treatment of HSDD in women. The authors searched medical databases from inception to June 17, 2015. Randomized clinical trials assessing the treatment effects of flibanserin in premenopausal and postmenopausal women were eligible for analysis. Primary efficacy outcomes included the number of satisfying sexual events (SSEs), eDiary sexual desire, and Female Sexual Function Index (FSFI) desire. Safety outcomes included four common adverse events: dizziness, somnolence, nausea, and fatigue.

The researchers evaluated five published and three unpublished studies involving a total of 5,914 women. Pooled mean differences for the change from baseline in SSE were 0.49 between flibanserin (100 mg) and placebo; 1.63 for eDiary desire; and 0.27 for FSFI desire. The risk ratio for study discontinuation because of adverse events was 2.19. The risk ratio for dizziness was 4.00 for flibanserin compared with placebo; 3.97 for somnolence; 2.35 for nausea; and 1.64 for fatigue. The women’s Mean Global Impression of Improvement scores indicated minimal improvement or no change.

The authors reported that treatment with flibanserin, on average, resulted in only one-half additional SSE per month while significantly increasing the risk of dizziness, somnolence, nausea, and fatigue compared with placebo. Overall, the quality of the clinical evidence was graded as “very low.”

The authors concluded: “Before flibanserin can be recommended in guidelines and clinical practice, future studies should include women from diverse populations, particularly women with comorbidities, medication use, and surgical menopause.”

Flibanserin has failed to gain a sizable following since its approval by the FDA, according to the BloombergBusiness website. Valeant Pharmaceuticals, the drug’s marketer, is facing intense scrutiny over its drug pricing, accounting, and distribution practices, and has lost more than two-thirds of its market value since August, Bloomberg says.

The International Society for the Study of Women’s Sexual Health, a physician group, has disputed the new study findings, pointing a finger at the way the investigation was conducted.

The JAMA report included studies that weren’t published and that used doses that aren’t currently approved, the society said in a statement. In addition, the study didn’t take into account the women’s distress levels from their condition. Nonetheless, the report found a benefit for flibanserin over placebo, the society said.

Sources: BloombergBusiness; March 1, 2016; and JAMA Internal Medicine; February 29, 2016.