RPRX .71 avg Still due FDA decision on continuing trials. Reply within 30 days of the request
THE WOODLANDS, Texas (AP) -- Repros Therapeutics Inc. said Monday it has asked regulators to allow it to resume clinical testing of its drug candidate Proellex, which was halted in August due to potential signs of liver damage in patients.
Proellex is designed to reduce menstrual bleeding associated with uterine fibroids and endometriosis. Repros said Monday it believes a smaller dose of the oral drug -- 12.5 milligrams or less -- would be safe and effective without the risk of side effects. It also said the side effects that were observed in the study -- liver damage and high levels of liver enzymes -- went away over time.
Uterine fibroids are noncancerous growths of muscle fibers inside the uterus. They can cause heavy menstrual bleeding, pelvic soreness and pain. Endometriosis is a condition in which a tissue similar to the uterine lining is found outside of the uterus, such as on the ovaries. The condition can cause pelvic pain and infertility. Repros said Proellex could provide a safe alternative for women who may otherwise have to seek hysterectomies.
Repros stopped a mid-stage trial of Proellex in August after observing higher levels of liver enzymes in 13 patients. The FDA placed a clinical hold on Proellex, which prevents Repros from testing the drug on people.
The company said it continued to monitor the patients with those high levels for six months after the trial was put on hold. The follow-up study ended in March, and Repros said all of the patients' liver enzyme levels returned to normal. That includes seven patients who had experienced serious side effects similar to hepatitis.
Repros said it believes the side effects were caused by high doses of Proellex as well as individual sensitivity to the drug.
Repros was testing 25-milligram and 50-milligram doses of Proellex in the trial, but discontinued the larger dose in July -- before the trial was placed on hold -- due to side effects. The company said it believes a 12.5-milligram dose will be safe and effective as a treatment for both uterine fibroids and endometriosis. It had tested that dose in earlier studies, and now believes it can develop an even lower dose that remains effective.
The company said liver damage associated with the 25 milligram dose could be minimized with careful dosing, but concluded that it would not be worth the risk.
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