Comparisons and correlations of 1-month recall vs 24-hour recall in patient-reported outcomes of an exploratory, phase 2b, randomized, double-blind, placebo-controlled clinical trial of sildenafil cream, 3.6% for the treatment of female sexual arousal disorder.

Background: Efficacy assessments in clinical trials of treatments for female sexual arousal disorder (FSAD) and other female sexual dysfunction (FSD) diagnoses rely on various patient-reported outcomes (PROs).

Aims: We sought to compare 1-month recall PRO measures among participants enrolled in a clinical trial who provided these data without (test population) vs with (control population) use of an at-home, 24-hour recall electronic diary (eDiary), capturing similar data.

Methods: Preplanned subset analysis as performed during a phase 2b, exploratory, randomized, placebo-controlled, double-blind study of sildenafil cream, 3.6% (sildenafil cream) among healthy premenopausal women with FSAD. Preliminary product efficacy was assessed via 1-month recall and 24-hour recall questionnaires. A subset of the participants, the Evaluation of Recall Subset [ERS] provided PROs via the 1-month recall instruments but did not provide data via the 24-hour recall eDiary.

Outcomes: Responses to the 1-month recall instruments were compared among ERS (test) vs non-ERS (control) participants. Among the non-ERS population, correlations between 1-month and 24-hour recall endpoints were calculated.

Results: There were no significant differences in the study co-primary 1-month recall efficacy endpoints, the Arousal Sensation (AS) domain of the 28-item Sexual Function Questionnaire (SFQ28) and the Female Sexual Distress Scale - Desire, Arousal, Orgasm question 14, among ERS vs non-ERS participants during the initial 1-month no-drug run-in period or the 1-month single-blind placebo run-in period (P values > .47). Scores on these 1-month recall PROs continued to be similar after randomization for sildenafil cream (P values > .30) and placebo cream (P values > .20) assigned ERS and non-ERS participants during the 3-month double-blind dosing period. There were strong correlations between the SFQ28 AS and eDiary AS scores during the no-drug run-in (R = 0.79, P < .01) and the single-blind run-in (R = 0.73 P < .001). During the double-blind dosing period, the SFQ28 AS score continued to be highly correlated with the eDiary AS score among sildenafil cream users (R = 0.83; P < .001) and placebo cream users (R = 0.8; 2 P < .001).

Clinical implications: There was no evidence that 1-month recall PRO instruments introduce recall bias; assessing arousal sensations with 24-hour vs 1-month PRO instruments is similar and either method could be used to assess efficacy depending on study objectives.

Strengths and limitations: This preplanned subset analysis compared efficacy of PROs based on recall duration. While the subset was preplanned, the study was powered to detect significant differences in the primary efficacy objectives, not among this subset analyses.

Conclusion: These data will be used in planning future efficacy assessments of sildenafil cream for FSAD.

Clinical trial registration: This clinical trial was registered with ClinicalTrials.gov, NCT04948151.