FDA Allows Repros To Conduct Phase I/II Clinical Trials On Proellex
By Cyndi Root
Repros Therapeutics Inc. announced in a press release that the Food and Drug Administration (FDA) has given the company guidance on Proellex and has approved Phase I and II clinical studies. The federal agency has approved two separate Investigational New Drug (IND) applications for uterine fibroids and endometriosis.
Uterine Fibroids
Uterine fibroids, also known as leiomyoma, are benign tumors in a woman’s uterus. Fibroids are usually, but not always, benign. They have varying growth patterns. Some are very small and others are very large, with every size in between. A woman may have just one tumor or many. Women can opt for surgical removal or take gonadotropin-releasing hormone (GnRH) drugs. Because GnRH drugs initiate a menopause-like condition with resulting bone loss, women should not take them for more than six months.
Endometriosis
Endometriosis occurs when endometrium tissue migrates from the uterus to other structures nearby. Common sites for endometriosis include the ovaries, fallopian tubes, the bladder, and the rectum. Endometriosis is known to travel to the skin, brain, and lungs. Women are treated with pain medications or hormone treatments and may elect to have surgery.
Proellex
Proellex, a New Chemical Entity (NCE), selectively blocks the progesterone receptor. Progesterone is active in many biological processes and its activities depend on the progesterone receptor (PR). Because Proellex only partially blocks the PR, it is called a selective progesterone receptor modulator (SPRM).
Proellex Clinical Trials
For the uterine fibroid trial, the FDA gave Repros guidance on inclusion/exclusion criteria and its preferred endpoint. The agency prefers that the primary efficacy endpoint be measured by a reduction in excessive menstrual bleeding. The FDA also indicated how it would like the company to measure these changes. Reprosintends to take the FDA’s guidance and provide additional data on symptom relief and tumor size.
Previous studies with Proellex have given Repros reliable data that Proellex is effective at 6 and 12 mg doses daily. The FDA specified in its guidance, that the highest dose should be no more than 12 mg daily. Repros intends to enroll less than 75 women for the trial and hopes to demonstrate that Proellex reduces bleeding. The company chose the number of women for the three-arm, parallel design, double blind trial because the small number of women should theoretically have a 90 percent success rate.