Responder Analyses from a Phase 2b Dose-Ranging Study of Bremelanotide

J Sex Med. 2019 Aug;16(8):1226-1235. doi: 10.1016/j.jsxm.2019.05.012. Epub 2019 Jul 2.


Background: Responder analyses are used to determine whether changes that occur during a clinical trial are clinically meaningful; for subjective endpoints such as those based on patient-reported outcomes (PROs), responder analyses are particularly useful.

Aim: To identify the minimal clinically important difference (MCID) for selected scores on questionnaires assessing female sexual functioning and to use these differences to analyze the response in a large, controlled, phase 2b, dose-finding study of bremelanotide in premenopausal women with hypoactive sexual desire disorder (HSDD) and mixed HSDD/female sexual arousal disorder (FSAD).

Methods: The responder analyses were performed for the change from baseline to end of study for a total of 7 endpoints. Each PRO endpoint was assessed using at least 1 of 4 types of responder analyses: a planned analysis anchored to MCIDs based on expert estimates (historical anchors); post hoc analyses based on self-reported global benefit; receiver operating characteristic (ROC) curves; and cumulative distribution function. The prespecified analysis groups were all female sexual dysfunction (FSD)-based diagnoses (all study participants), those with HSDD alone, and a combined group of those with FSAD alone plus those with mixed HSDD/FSAD. Post hoc analyses were also performed for subjects with mixed HSDD/FSAD with a primary diagnosis of HSDD.

Outcomes: MCIDs based on the ROC curves for changes in Female Sexual Function Index-desire domain, Female Sexual Distress Scale-Desire/Arousal/Orgasm (FSDS-DAO) total score, FSDS-DAO item 13 and 14 scores, and number of satisfying sexual events.

Results: Outcomes matched those based on input from clinical experts. For all 7 endpoints, responder rates at the 1.75 mg dose in the overall modified intention-to-treat population achieved statistical significance compared with placebo (P ≤ .03).

Clinical implications: These responder definitions were subsequently used in the bremelanotide phase 3 registration studies (RECONNECT) that evaluated the safety and efficacy of the bremelanotide 1.75 mg subcutaneous dose in premenopausal women with HSDD.

Strengths & limitations: MCIDs for this study were based on changes from a single-blind phase to account for changes due to the placebo effect. These analyses were restricted to a study population composed only of premenopausal women with a clinical diagnosis of HSDD and/or FSAD and were based on data from the same clinical trial.

Conclusion: Bremelanotide was safe and well tolerated and demonstrated significant improvement in efficacy vs placebo in the phase 2b trial. The multiple responder analyses offer a valuable approach for determining clinically important effects of bremelanotide for HSDD and FSAD. Althof S, Derogatis LR, Greenberg S, et al. Responder Analyses from a Phase 2b Dose-Ranging Study of Bremelanotide. J Sex Med 2019;16:1226-1235.

Keywords: Bremelanotide; Female Sexual Dysfunction; Hypoactive Sexual Desire Disorder; Minimal Clinically Important Difference; Responder Analyses.

Publication types

  • Clinical Trial, Phase II
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Double-Blind Method
  • Female
  • Humans
  • Libido / drug effects
  • Peptides, Cyclic / administration & dosage*
  • Premenopause*
  • Sexual Dysfunction, Physiological / drug therapy*
  • Sexual Dysfunctions, Psychological / diagnosis
  • Sexual Dysfunctions, Psychological / drug therapy*
  • Single-Blind Method
  • Surveys and Questionnaires
  • alpha-MSH / administration & dosage*


  • Peptides, Cyclic
  • alpha-MSH
  • bremelanotide