Satisfying sexual events as outcome measures in clinical trial of female sexual dysfunction

Assessing the sexual response in women with female sexual dysfunctions (FSDs) in clinical trials remains difficult. Part of the challenge is the development of meaningful and valid end points that capture the complexity of women's sexual response.

The purpose of this review is to highlight the shortcomings of daily diaries and the limitations of satisfying sexual events (SSEs) as primary end points in clinical trials of women with hypoactive sexual desire disorder (HSDD) as recommended by the Food and Drug Administration (FDA) in their draft guidance on standards for clinical trials in women with FSD.

Clinical trials in women with HSDD using SSEs as primary end points were reviewed.

The agreement between three outcome measures (SSEs, desire, and distress) was assessed to illustrate to what degree improvements in SSEs were in agreement with improvements in sexual desire and/or personal distress.

Nine placebo-controlled randomized trials in women with HSDD were reviewed: seven with transdermal testosterone and two with flibanserin. In four trials, all using transdermal testosterone 300 µg/day had agreement between changes in SSEs, desire, and distress. In five studies (testosterone 300 µg/day, n = 2; testosterone 150 µg/day, n = 1; flibanserin n = 2), changes in SSEs did not correlate with changes in desire and/or distress and vice versa. It should be noted that in the flibanserin trials, SSEs did correlate with desire assessed using the Female Sexual Function Index but not when it was assessed using the eDiary.

Findings in the literature do not uniformly support the recommendations from the FDA draft guidance to use diary measures in clinical trials of HSDD as primary end points. Patient-reported outcomes appear to be better suited to capture the multidimensional and more subjective information collected in trials of FSD.