Repros Therapeutics Inc (NASDAQ:RPRX) investors have a reason to smile this afternoon, after the drug maker reported positive topline results for both its pooled oral and vaginal delivery Phase 2 studies in the treatment of uterine fibroids.
Repros shares are rising nearly 14% to $2.14 in after-hours trading Monday.
Both studies enrolled women with confirmed fibroids by MRI at baseline and who were experiencing more than 80 mL of blood loss during menses as confirmed by alkaline hematin assessment. Proellex® at doses of both 6 and 12 mg, delivered by either route, substantially and significantly reduced excessive menstrual bleeding, the key symptom of uterine fibroids and the primary endpoint of the studies. The study of vaginal delivery enrolled 42 subjects and the oral delivery study’s intent-to-treat population included 41 subjects.
Amenorrhea, cessation of menses, is known to occur when a sufficiently high plasma concentration of Proellex® is achieved. Subjects received 18 weeks of blinded treatment and were then withdrawn from the study medication to allow for menses. After menses occurred, a second 18 week course of treatment ensued. The study treatment assignments remained blinded to the subjects, physicians and those managing the study and data.
The incidence of amenorrhea in active treatment groups consistently showed a statistically significantly difference from the rate in placebo-treated subjects with both routes of administration. At the end of the second course of treatment (36 weeks total active treatment, or Last Observation Carried Forward, LOCF), 92.9% of oral Proellex®-treated subjects achieved amenorrhea, while only 50% of vaginally treated subjects stopped menses. The oral dosage form provided for consistent suppression of menses with evidence of a dose response. Furthermore, among those women who completed the second 18 week course of oral drug administration, 100% of the women at the 12 mg dose exhibited amenorrhea, whereas 88.9% of women on the 6 mg dose achieved amenorrhea.
Along with changes in menstrual patterns, fibroid size, measured by MRI, was reduced in volume. Fibroid volume decreased in the oral Proellex®-treated arms by a median of 42.0% (LOCF) and was statistically different from the change from baseline volume in the placebo subjects (0%, p = 0.0004). For women who completed the two 18 week courses of treatment, fibroid size reduction for the 12 mg oral and 6 mg oral doses was 58.2% and 32.9%, respectively, providing some evidence of a dose response effect.
The Uterine Fibroid Symptom Quality of Life Survey (UFSQOL) was utilized in this study. The UFSQOL assesses distress from both bleeding and the bulk symptoms of uterine fibroids. Bulk symptoms include distress associated with pelvic pressure, frequent urination and fatigue. Proellex®-treated subjects experienced a LOCF median 70.9% improvement while placebo-treated subjects reported a 37.5% improvement (p = 0.0211).
The drug was generally well tolerated.
Joseph Podolski, President and CEO of Repros, commented, “We believe the benefit:risk profile of Proellex® could afford a significant advantage over GnRH agonists and antagonists in the treatment of uterine fibroids. The longer treatment period and apparent improvement in efficacy based on the incidence of amenorrhea compared to other selective progesterone antagonists is also encouraging.”
The Company plans to request, before the end of this year, a meeting with the FDA to discuss Phase 3 development of the oral dosage form. (Original Source)
Repros Therapeutics, Inc. is a development stage company. The company operates as a biopharmaceutical company, which focuses on the development of new drugs to treat hormonal and reproductive system disorders. Its current product pipeline consists of Enclomiphene and Proellex.