GTx, Inc. (Nasdaq:GTXI) today announced additional results from a Phase 2 proof-of-concept clinical trial of 3 mg enobosarm administered orally in postmenopausal women with stress urinary incontinence (SUI), including magnetic resonance imaging (MRI) results from patients’ pelvic floor muscle. New data in a subset of women also suggests a positive treatment effect of enobosarm for urge incontinence (UI) suggesting a possible treatment effect for women with mixed incontinence. Results from a pre-specified analysis of MRI data demonstrate a statistically significant increase in pelvic floor muscle thickness and urethral muscle diameter after enobosarm treatment. Treatment with enobosarm also reduced mean UI episodes by approximately 68 percent in patients who experienced UI as well as SUI, based on a post hoc analysis of a subset of women with both UI and SUI. These results were outlined during a podium presentation which took place at the Society of Urodynamics, Female Pelvic Medicine, & Urogenital Reconstruction (SUFU) 2018 Meeting on Saturday, March 3, 2018. The presentation included clinical data from all 18 patients completing 12 weeks of enobosarm treatment, which, as previously reported, demonstrated an 81 percent reduction in the number of mean stress leaks per day (the primary endpoint of the clinical trial), as well as additional data demonstrating duration of response following completion of treatment, including nine patients who have now reached seven months post-treatment.
"Enobosarm’s overall treatment effect was consistent with previously announced results, and importantly, these new results demonstrate that enobosarm may address a broader treatment need since many women suffer from symptoms of both stress and urge incontinence, also known as mixed incontinence," said Kenneth M. Peters, M.D., Chairman of Urology, Oakland University William Beaumont School of Medicine, and the principal investigator in the trial. "In addition, with the MRI results, we are seeing anatomical changes supporting enobosarm’s mechanism of action on pelvic floor muscle."
Magnetic Resonance Imaging (MRI) Summary of Results
Magnetic resonance imaging (MRI) was used to quantitatively measure muscle in the pelvic floor of 17 women at 12 weeks compared to their baseline. The results showed a statistically significant increase in several important measurements and support the mechanism of action of enobosarm on the pelvic floor.
- At week 12, mean levator ani muscle thickness increased 1.15 mm (p=0.006) from a baseline measurement of 4.79 mm.
- At week 12, mean inner urethral muscle diameter increased 0.7 mm (p=0.002) from a baseline measurement of 10.7 mm.
- At week 12, mean outer urethral muscle diameter increased 0.7 mm (p=0.0003) from a baseline measurement of 15.4 mm.
Urge Incontinence Summary of Results
While all of the women in the trial had predominant SUI, some also experienced urge incontinence (UI). Eleven of the 18 women completing 12 weeks of treatment were determined to have both SUI and UI at baseline, and these 11 women with mixed incontinence demonstrated a mean reduction in their UI episodes of approximately 68 percent.
- Urge leaks decreased from a mean of 1.41 leaks per day at baseline, to 0.45 leaks per day;
- 9 of 11 women demonstrated a reduction in their number of UI leaks, compared to baseline, with 8 of 11 demonstrating a clinically meaningful reduction in their UI episodes per day of at least 50 percent; and
- Median Medical, Epidemiologic and Social Aspects of Aging (MESA) scores for UI decreased from 56 percent to 22 percent.
Stress Urinary Incontinence Summary of Results
Consistent with previous findings, at the end of the 12-week treatment period, all of the 18 enobosarm-treated women showed a clinically meaningful reduction in stress urinary incontinence episodes per day (the primary endpoint of the trial).
- Mean stress leaks decreased by 81 percent from baseline;
- Stress leaks decreased from a mean of 5.17 leaks per day at baseline to 1.00 leak per day;
- All 18 patients demonstrated clinically meaningful reductions in stress urinary incontinence episodes per day, compared to baseline, of at least 50 percent; and ...
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