(By Balaseshan) Repros Therapeutics Inc. (NASDAQ:RPRX) said the U.S. regulatory authorities provided guidance for a phase 2 study of low dose oral Proellex in the treatment of endometriosis.
The key elements of the guidance are: trial patient population includes women diagnosed within the last 5 years via laparoscopic or other surgical techniques and as having severe endometriosis requiring narcotic analgesics.
The key elements also include: the primary endpoint is percent reduction in narcotic usage to control endometriosis related pelvic pain from baseline to the end of the four month study comparing placebo to Proellex; and other endpoints include reduction in individual elements of endometriosis related pain and overall analgesic usage.
It is estimated that nearly 5 million women of reproductive age in the U.S. and Canada suffer from endometriosis. The disorder is characterized by severe pelvic abdominal pain that, in many cases, peaks during menses. In severe cases hysterectomies are the intervention of last resort.
Repros plans to submit the revised protocol to the FDA as soon as practicable. Once received, the FDA agreed to review the design within 30 days, at which time, if the protocol is acceptable, Repros could begin the Phase 2 trial in the fourth quarter of this year. The company plans to enroll up to 90 women into the study (30 per arm).
The company believes prior experience with higher dose Proellex bodes well for the eventual outcome of the trial. In previous studies of oral Proellex in women with severe endometriosis at doses of 25 and 50 mg, Proellex in comparison to placebo statistically significantly reduced the three elements of endometriosis related pain.
The three elements of pain are dysmenorrhea or painful menses, dyspareunia or painful sex and non menstrual pelvic pain. In addition to the statistically significant reduction in all three pain elements, there was also a statistically significant reduction in the need for over the counter or narcotic analgesics used to control the endometriosis related pain in the Proellex arm.
Notably, there was no difference in the response between the two active doses. The company believes the primary driver in pain relief associated with the use of Proellex is the suppression of menses.
Both the 25 and 50 mg dose of Proellex suppress menses to the same extent. Importantly, the two doses in the proposed Phase 2 study, 6 and 12 mg, have been shown to suppress menses equivalent to the two higher doses.
RPRX closed Monday's regular session up 0.65% at $10.84. The stock has been trading between $3.34 and $11.54 for the past 52 weeks.