Sildenafil Cream, 3.6%
Female sexual arousal disorder (FSAD) is the inability to reach or maintain a sufficient physical response to sexual stimulation. Market research suggests that 16% of women ages 21 to 60, or approximately 10 million women in the U.S., are distressed from experiencing symptoms associated with FSAD, including low or no sexual arousal, and are seeking a solution to improve their condition. To put the market opportunity for an FDA-approved FSAD treatment in context, the prevalence of complete erectile dysfunction (ED) in men is estimated to be about 5% of men at age 40, increasing to about 15% at age 70.
There are currently no FDA-approved therapies for FSAD. Orally administered sildenafil, a phosphodiesterase-5 (PDE-5) inhibitor, received FDA approval in 1998 for the treatment of erectile dysfunction in men and is marketed under the brand name Viagra®. Given the underlying pathophysiologic similarities of ED and FSAD, using sildenafil to direct blood to the genitals before sexual activity could provide a potential improvement in genital arousal response and overall sexual experience for women as it does in men.
Sildenafil Cream, 3.6% is an investigational proprietary topical formulation of sildenafil being developed as a first-in-category option for women for the treatment of FSAD. Unlike the oral formulations of PDE-5 inhibitors, Sildenafil Cream is applied locally to the vaginal tissue and is designed to facilitate vasodilation and increased blood flow directly to the genital tissue to improve the physical arousal response symptoms commonly associated with FSAD while avoiding systemic side effects observed with oral formulations of sildenafil.
Sildenafil Cream, 3.6% has been previously evaluated in Phase 1 and Phase 2a clinical studies. In a Phase 1 clinical study in 20 healthy post-menopausal women, topical sildenafil cream was safe and well tolerated at clinically relevant doses, and study subjects reported favorable product characteristics: easy to use and readily absorbed. In a Phase 2a study in women with FSAD (15 pre-menopausal and 16 post-menopausal), Sildenafil Cream increased measurable blood flow to the genital tissue compared to placebo cream. Further, data from a thermography study in healthy women demonstrated significantly greater increases in genital temperature after administration of Sildenafil Cream compared to placebo cream, indicating a positive impact on genital blood flow during the 30-minute testing session, with statistical separation from placebo within the first 15 minutes after dosing.
We also completed a content validity study designed to identify and document the genital arousal symptoms that are the most important and relevant to women with FSAD. The findings of this study helped facilitate alignment with the FDA on acceptable efficacy endpoints for the Phase 2b RESPOND study and a future Phase 3 program.
Sildenafil Cream, 3.6% is currently being evaluated in an exploratory Phase 2b study in which the study participants use Sildenafil Cream and placebo cream over 12 weeks in their home setting, following both a non-drug and placebo cream run-in period. The Phase 2b RESPOND clinical study is a multi-center, double-blind, placebo-controlled study to evaluate the efficacy and safety of Sildenafil Cream, 3.6% in premenopausal patients with FSAD. A total of approximately 160 to 170 subjects are expected to complete the study for inclusion in the topline data assessment targeted for the second quarter of 2023.
The Phase 2b RESPOND study is a first of its kind Phase 2b study that includes patient reported outcome (PRO) instruments to screen eligible women with FSAD and a number of primary, secondary, and exploratory PRO assessments to measure improvement in localized genital sensations of arousal and reduction in the distress that women experience with FSAD. There are no FDA-approved treatments for FSAD and thus there are no efficacy endpoints that have been previously validated in Phase 3 pivotal studies for potential treatments for FSAD. The RESPOND study is designed to test the sensitivity of several efficacy endpoints and their ability to determine a treatment effect of Sildenafil Cream compared to placebo to inform the ongoing development program. The primary efficacy endpoint of the Phase 2b RESPOND study is a composite endpoint that includes patient-reported improvement in genital sensations of arousal and reduction in distress associated with FSAD. (ClinicalTrials.gov Identifier: NCT04948151)
Read more about the ongoing Phase2b clinical study here.
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