Repros reports promising results from pilot study of Proellex

In preparation for conducting a thorough QT study (TQT), Repros has completed a pilot trial dosing healthy female volunteers for seven days with Proellex 200mg. Formal QT studies are dosed for five days. This Proellex dose is four to eight times the dose shown to be effective in our uterine fibroid and endometriosis trials. Subjects all had baseline electrocardiograms (ECGs) and blood tests for safety and were dosed with Proellex 200mg daily for seven days.

Proellex, is a selective blocker of the progesterone receptor and is being developed for the treatment of symptoms associated with uterine fibroids and endometriosis. The study was designed to assess the potential for QT prolongation, an indicator of potential adverse cardiac effects and a major safety consideration for the FDA.

ECGs were done at baseline and two hours after dosing on days one, three, five, and seven. In addition Proellex pharmacokinetic assessments were performed at frequent intervals on days one and seven for 24 and 36 hours respectively. Analysis of the ECGs on days one, three, five, and seven of dosing showed that compared with baseline the change in QTc interval at two hours, which approximates the maximum blood concentration after dosing, was 0.20, -2.71, 4.00 and -5.33 milliseconds (ms) respectively. Mean (SD) QTc intervals at baseline and day seven were 409.2 (11.34) and 406.67 (9.29) respectively.

None of the measurements during treatment were statistically different from each other or baseline. Mean Proellex blood levels at two hours after dosing on days one and seven were 824 and 2121.7ng/mL respectively. The increasing blood concentration over the seven days of exposure is due to the fact that the compound has a half life of 17 hours. Despite this increase in Proellex concentration over seven days the QTc did not change.