UPDATE 3-FDA partially lifts clinical hold on Repros' drug

BANGALORE, June 11 (Reuters) - Repros Therapeutics Inc (RPRX.O) said the U.S. health regulator lifted the full clinical hold on its lead drug for the treatment of uterine fibroids, and allowed Repros to run a single study on the drug under a partial clinical hold, sending its shares up as much as 44 percent.

Ladenburg Thalmann & Co analyst Matthew Kaplan, who has a "neutral" rating on the stock, said it was difficult to place a bet at this time on the success of the new study.

"It's difficult to predict and that's why they have to go through the test to establish the correct doses," Kaplan added.

The new low-dose study on the drug Proellex, which was put on hold by regulators in 2009 as patients receiving higher doses of the drug showed signs of liver toxicity, is designed to explore both safety and signals of efficacy.

Repros said it was sufficiently capitalized to commence the study due to the proceeds it generated from a direct sale of common shares. [ID:nWNAB9206]

Kaplan, who is the sole analyst covering the company, said the company had enough cash to initiate the study but not enough to get the product into the market, if and when it gets approval.

The new study will test 5 different doses of Proellex starting with 1 mg and higher doses will not be studied until Repros is confident that it is safe to proceed to the next dose and reports the safety findings to the regulator.

Repros said the toxicity experienced in its previous study was dose dependent and the lower doses that will now be tested, are outside the range where toxicity was previously seen.

In the new study, each dose will be compared to a dummy drug, with weekly assessments of liver function in both the groups, the company said.

The company will also monitor changes in menstrual bleeding patterns and ovulation as well as changes in endometrial or inner membrane thickness of the uterus.

The company plans to proceed with the manufacture of the lower doses of Proellex capsules and hopes to begin dosing subjects this summer. It expects to complete the trial within roughly 18 months after the first dose.

Shares of the company were up about 19 percent at 57 cents in Friday afternoon trade on Nasdaq. They had touched a high of 69 cents earlier the session. (Reporting by Esha Dey and Krishnakali Sengupta in Bangalore; Editing by Jarshad Kakkrakandy)