Stress Urinary Incontinence (SUI), the inability to control urine flow, occurs when the involved sphincter and support muscles become weak or do not function properly. These muscles lose their tone with age. Estrogen therapy (as part of Hormone Replacement Therapy, or HRT) in postmenopausal women can be helpful, but there is a concern with the use of estrogen therapy and the increased risk of uterine or breast cancer.
The muscles responsible for controlling urine flow have a high number of androgen receptors and require hormone binding for optimal function. As the amount of hormones produced by the ovaries decreases with age, these muscles can become atrophied.
GTx-024 (enobosarm, Ostarine®) has been shown, in preclinical work, to increase muscle mass in these same muscles responsible for SUI. The predominant SARM effect, in preclinical work, was on the levator ani muscle, the target for SUI muscle mass improvement.
We have an ongoing clinical trial of enobosarm in postmenopausal women with SUI to evaluate the drug’s ability to increase muscle mass and strength in the pelvic floor muscles to reduce involuntary urinary leakage or incontinence.