Repros Therapeutics Offers Topline Results from Phase 2 Study of Proellex for Uterine Fibroids
Repros Therapeutics Inc.^® (Nasdaq: RPRX) today reported top line results from its Phase 2 study of vaginally administered Proellex in the treatment of symptomatic fibroids. The results from the study suggest the 12 mg dose may provide clinical benefit to women suffering from symptomatic uterine fibroids. The Company plans to request an end of Phase 2 meeting with the FDA as soon as practicable.
The primary endpoint in the study was change in Pictorial Blood Loss Assessment (PBAC). Secondary endpoints included change in Uterine Fibroid Symptom Quality of Life (UFSQOL) and change in fibroid volume by MRI assessment.
A total of 40 women were enrolled into the study into one of four groups, 3 mg (n=9), 6 mg (n=9), 12 mg (n=12) and 24 mg (n=10). The following table reports the data from those subjects that completed the study. Unexpectedly, the 24 mg dose exhibited lower exposure than the 12 mg dose which, the Company believes, may result from the hydrophobic nature of the active ingredient and the low volume of excipient used in order to prevent vaginal leakage. Based on these findings, the Company plans to only pursue the 12 mg dose in Phase 3. The MRI report for the 24 mg end of dosing visit is not available at this time but is not expected to be an improvement on the 12 mg dose. In the table, the larger the reduction (negative number), the better the result.
Dose (n=subjects Mean % Change in Mean % Change in Mean % Change in Fibroid completing study) PBAC (StDev) UFSQOL (StDev) Volume (StDev) 3 mg (n=8) -58.3 (40.4) -59.3 (41.35) 1 (17.78) 6 mg (n=7) 56.8 (139.3) -6.47 (72.5) -3.1 (20.04) 12 mg (n=11) -84.6 (24.9) -79.1 (31.72) -28.0 (13.3) 24 mg (n=5) -85.5 (20.4) -65 (78.3) Not available
The 12 mg dose exhibited a statistically significant difference (p<0.05) compared to the pooled data from the 3 and 6 mg doses for all three measures. The 6 mg dose group data was affected by a single subject (given the small number of subjects) that exhibited continuous uterine bleeding. This subject also recorded the lone SAE probably associated with administration of the drug following completion of the dosing period. The Company believes this observation was associated with the low level of exposure of the 6 mg dose as well as sporadic (poor compliance) administration of the drug in this individual as exhibited by trough level analysis of the active ingredient at each clinical visit (every two weeks).
The reduction in fibroid volume was significant for the 12 mg dose as compared to either the 3 or 6 mg dose group (p=0.002 and p=0.01, respectively). The magnitude of the change and statistical significance are remarkable given the small number of subjects enrolled in the study.
58% of the women on the 12 mg dose ceased menstruation whereas 18% of the combined 3 and 6 mg doses stopped. The Company believes the incomplete cessation of menses at the 12 mg dose was a result of sporadic (poor compliance) administration of the drug in some of the subjects which was confirmed by evidence, on occasion, of no trough levels of active drug in those individuals that did not cease menstruation.
The Company has put in place an extension study to begin to build the 1 year exposure safety data base that will be required for an eventual NDA submission. To date, 15 of the 40 subjects have elected to enroll in the extension study.
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