Benzinga | Mar 24, 2021 08:06AM EDT

Dar Bioscience Announces Initiation Of Phase 2b RESPOND Study Of Sildenafil Cream, 3.6% In Women With Female Sexual Arousal Disorder

Dar? Bioscience, Inc. (NASDAQ:DARE), a leader in women's health innovation, and Strategic Science & Technologies, LLC (SST), a Cambridge, MA based novel topical drug delivery company, today announced the initiation of the Phase 2b RESPOND clinical study of Sildenafil Cream, 3.6% for the treatment of female sexual arousal disorder (FSAD).



Sildenafil Cream is a proprietary topical formulation of sildenafil, a phosphodiesterase-5 (PDE-5) inhibitor, being developed as a first-in-category option for the treatment of FSAD. FSAD is the inability to reach or maintain a sufficient physical response to sexual stimulation and, of the various types of female sexual dysfunction disorders, FSAD is most analogous to erectile dysfunction (ED) in men. Sildenafil is the active ingredient in a tablet for oral administration currently marketed under the brand name Viagra(r) for the treatment of erectile dysfunction in men.

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. If clinical development is successful, Sildenafil Cream has the potential to be the first FDA-approved FSAD treatment option.

The Phase 2b RESPOND study will evaluate Sildenafil Cream compared to placebo cream in pre- and peri-menopausal women over 12 weeks of at-home use following both a non-drug and placebo run-in period. Patient reported outcome (PRO) instruments will be used to screen eligible women with FSAD and to measure achievement of the primary efficacy endpoint, namely improvement in localized genital sensations of arousal and reduction in the distress that women with FSAD experience.

"We are honored to commence the Phase 2b study of Sildenafil Cream. Commencing the study now positions us for a potential topline data readout by the end of 2021, and over the next several months we will provide updates on our progress toward that target. Women have suffered far too long without a viable intervention to address FSAD and we believe Sildenafil Cream has the potential to be the first prescription product for this condition," said Sabrina Martucci Johnson, President and CEO of Dar? Bioscience. "This study is a significant milestone for Dar? and our partner SST as we seek to bring to market a product that could address an important unmet need for women. The FSAD market is estimated to be as significant, if not more so, as the erectile dysfunction market in both the U.S. and the rest of the world."

Market research suggests that 16% of women in the U.S. ages 21 to 60, or approximately 10 million women, are distressed from experiencing symptoms of low or no sexual arousal and seeking a solution to improve their condition. To put the market opportunity for an FDA-approved FSAD treatment in context, the prevalence of complete ED in men is estimated to be about 5% of men at age 40, increasing to about 15% at age 70.

"This is an important milestone in the field of female sexual dysfunction," said Dr. Andrew Goldstein, Medical Advisor of Dar? Bioscience and Past President of The International Society for the Study of Women's Sexual Health, as well as co-editor of the Textbook of Female Sexual Function and Dysfunction: Diagnosis and Treatment. "It is exciting to be working at the cutting edge of research focused on women's sexual health and to advance a potential first-in-category treatment option for women suffering with FSAD."

About FSAD

FSAD is distinct from hypoactive sexual desire disorder (HSDD) in women, which is characterized primarily by a lack of sexual desire. FSAD is a condition characterized primarily by a persistent or recurrent inability to attain or maintain sufficient genital arousal (an adequate lubrication-swelling response) during sexual activity, frequently resulting in distress or interpersonal difficulty. As with erectile dysfunction in men, FSAD in women is associated with insufficient blood flow to the genitalia.

About Sildenafil Cream and the Phase 2b RESPOND Study

Sildenafil Cream is an investigational proprietary cream formulation of sildenafil, a PDE-5 inhibitor, designed for topical administration to the vulva and vagina to increase genital blood flow and provide improvements in the female genital arousal response, while avoiding systemic side effects observed with oral formulations of sildenafil. Sildenafil Cream 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 of dosing.

Prior to commencement of the Phase 2b RESPOND clinical study of Sildenafil Cream, Dar? previously 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 that study helped facilitate alignment with the FDA on acceptable efficacy endpoints for the Phase 2b RESPOND study and future Phase 3 program. The Phase 2b RESPOND study is expected to randomize 400 to 590 subjects into the double-blind dosing period from 40 to 50 sites in the U.S. to ensure a total of 300 (150:150) to 440 (220:220) subjects complete the 12-week double-blind dosing period. The final study sample size will be determined by a single interim analysis for unblinded sample size re-estimation, based on the study's adaptive design. An adaptive design implemented in accordance with the FDA's Guidance for Industry on adaptive designs for clinical trials of drugs mitigates the risk of the study being underpowered if the true treatment effect and variability are significantly different from estimates based on published data but are still clinically meaningful. The target timeline for topline data readout of the Phase 2b RESPOND study assumes an increase in sample size above 400 randomized subjects is not required. The primary efficacy endpoint of the study is a composite endpoint that includes patient-reported improvement in genital sensations of arousal and reduction in distress associated with FSAD.

About Dar? Bioscience