Repros Announces Positive Findings in Proellex® Study

THE WOODLANDS, Texas -- Repros Therapeutics Inc. (NasdaqGM:RPRX) has released strong results from its completed extension safety study of Proellex in the chronic treatment of the symptoms associated with uterine fibroids. To date there have been no abnormal histological findings from the endometrial biopsies taken post menses after cessation of drug administration.

Currently, results from 13 women who had endometrial biopsies post menses following last dose of drug in a two-drug cycle extension study of Proellex in the treatment of symptoms associated with uterine fibroids are available. These women have been exposed to Proellex for one three-month and two four-month drug cycles to help control the symptoms of their uterine fibroids. These three cycles have covered a span of two and one half years which exceeds current FDA guidance for the duration of exposure to hormonal drugs.

The biopsies have been read by a panel of three expert pathologists all of whom will remain blinded to the treatment allocations until all of the final biopsies from this study have been read. The panel is led by Dr. George Mutter, Associate Professor of Pathology at Harvard Medical School, Department of Pathology, Brigham and Women’s Hospital. Dr. Mutter is a leading expert in the interpretation of gynecological histology and pathology.

Results of assessments of the post menses tissues are that of a benign endometrium. While previous end of drug cycle biopsies from these subjects all had histological changes consistent with those induced by progesterone receptor modulators (Proellex class of drugs), none of these post drug cessation biopsies reflected any of those histological changes. These key findings indicate that the effects of Proellex on the endometrium are present during drug exposure and are reversible upon cessation of drug treatment.

Repros has described in previous communications that it had developed a unique approach to dosing with Proellex which treats women for four months (16 weeks) and then stops treatment to create an “off drug interval” until the next menstrual period commences at which time treatment recommences for four months. These cyclical treatments are designed to be used for chronic treatment of symptomatic uterine fibroids and endometriosis. The rationale for this treatment regimen is that most of the reported bleeding events in previous studies occurred after 16 weeks of continuous treatment and were accompanied by endometrial thickening. By allowing a menstrual flow to occur after treatment withdrawal, the endometrium is essentially refreshed and the tendency toward a progressive endometrial thickening eliminated.

Joseph S. Podolski commented, “The importance of these findings can not be overstated. We believe this is a key finding. The consistency of endometrial effects on and off Proellex are strong and suggestive of a therapy that may have far reaching potential in diseases where progesterone has been implicated. The underlying theme for the action of Proellex is one of an agent that is anti-proliferative and pro-apoptotic and not the proliferative effects noticed in the development of some of the selective estrogen receptor modulators.”

He further noted that the Company’s pivotal Phase 3 efficacy and long-term safety studies all include endometrial biopsies and these findings will be strengthened by continued observations which should further support Proellex as an effective and safe therapy in the treatment of a variety of female disorders.

About Repros Therapeutics Inc.
Repros Therapeutics focuses on the development of oral small molecule drugs for major unmet medical needs that treat male and female reproductive disorders.

Proellex® is a selective blocker of the progesterone receptor and is being developed for the treatment of symptoms associated with uterine fibroids and endometriosis.