AUA 2018: Oral Enobosarm Shows Promising Activity in Post-Menopausal Women with Stress Urinary Incontinence: Results of a Phase 2 Study 

San Francisco, CA ( This session featured several studies that demonstrated possible complications of synthetic mesh mid urethral slings, a mainstay of treatment for stress urinary incontinence. The AUA/SUFU guidelines on treatment of SUI recommend continence pessaries, vaginal inserts, and pelvic floor muscle exercises as non-surgical treatment options. 1 There are no effective pharmacologic agents for the treatment of SUI. Testosterone can induce skeletal muscle hypertrophy in the pelvic floor and low serum testosterone levels are associated with an increased likelihood of SUI in women.2 

Enobosarm is a selective androgen receptor modulator (SARM), which was initially tested in clinical trials for use in the treatment of muscle wasting for patients with lung cancer, and has been used safely in over 1700 patients for other conditions. SARMs are designed to modulate the androgen receptor, promoting anabolic effects on skeletal muscle, without the unwanted side effects of androgen therapy. The authors present a phase 2 study of the use of oral enobosarm in the treatment of SUI in women. 

18 patients were enrolled, and enrollment was closed early due to highly positive results in the initial patients. Patient were all post- menopausal. They received one 3mg pill daily for twelve weeks, at which the primary endpoints were measured. The subjects were then followed for 40 weeks. Primary outcome was number of stress incontinence episodes per day on 3-day voiding diary. The secondary endpoints were daily voids, pad weight, bladder stress test, change in pelvic floor muscles by MRI, and quality of life (QOL) assessed by questionnaires. 

The 18 patients were an average age of 61.4 years, with mean BMI of 31.8. Mean stress leaks per day decreased from 5.7 to 1.0 per day.  Mean pad weight decreased by 71%.  Durability was assessed at 40 weeks, and and 16/18 patients maintained 50% improvement from baseline in the primary outcome of leaks per day. There was improvement in QOL by all measures (PGI-S, UDI-6, PGI-I,IIQ-7). In addition there was improvement in sexual function as measured by the Female Sexual Function Index Questionnaire; specifically, 1/18 patients had normal sexual function prior to treatment, and 8/18 had normal sexual function after treatment. MRI showed an increase in levator ani muscle thickness and urethral inner and outer diameter after treatment. There were no serious adverse events. 

Overall, enobosarm is a promising treatment for women with SUI. While the results demonstrate dramatic improvement in symptoms and quality of life, caution is needed in their interpretation due to the lack of placebo group for comparison.  However, much of the controversy surrounding the use of mesh will be obsolete if an effective, safe medical treatment for SUI becomes available. Many in the audience were excited for future studies of the use of SARMs for treatment of SUI. 

Presented by: Kenneth Peters, MD; Beaumont Hospital 

1. Kobashi KC, Albo ME, Dmochowski RR, et al. Surgical Treatment of Female Stress Urinary Incontinence: AUA/SUFU Guideline. J Urol. 2017;198(4):875-883. doi:10.1016/j.juro.2017.06.061 
2. Kim MM, Kreydin EI. The Association of Serum Testosterone Levels and Urinary Incontinence in Women. J Urol. 2018;199(2):52

Written by: Dena Moskowitz, MD; Fellow, Female Pelvic Medicine and Reconstructive Surgery, Virginia Mason Medical Center Twitter: @demoskowitz at the 2018 AUA Annual Meeting - May 18 - 21, 2018 – San Francisco, CA USA