UPDATE 2-Columbia Labs' menstrual-pain drug fails in trial

(Recasts, adds analysts' comments, updates share movement)

By Anand Basu

BANGALORE, Sept 29 (Reuters) - Columbia Laboratories Inc (CBRX.O) said its experimental treatment for menstrual pain failed to meet the main goal in a mid-stage trial, knocking its shares down as much as 38 percent.

These were top-line results, and the company hopes to have something more definitive to report from the complete analysis of the trial data during its third-quarter earnings conference call, finance chief James Meer said by phone.

He added that while the company was looking for a partner for the product -- vaginally-administered lidocaine -- it had not gone too far down the path as it first wanted to see what the final data looked like.

Caris & Co analyst David Moskowitz said he no longer believes a partnership for the product is forthcoming in the near term, given the failure of the product to meet its main goal, and downgraded the stock to "above average" from "buy."

The trial enrolled 70 women with a history of moderate to severe dysmenorrhea. Each woman received either lidocaine or the dummy drug in consecutive menstrual cycles.

Lidocaine, Columbia's treatment for dysmenorrhea, did not achieve the primary endpoint of significantly reducing uterine cramping and pain, versus the dummy drug.

The trial, however, showed no difference in safety for lidocaine compared to placebo and the data suggested a trend for patients to favor their lidocaine treatment cycle, Chief Executive Robert Mills said in a statement.

"We are evaluating if it is feasible to enhance this lidocaine effect through modifications to the dosing regimen and treatment protocol," Mills said in a statement.

Rodman & Renshaw analyst Thomas Shrader said a more frequent dosing regimen may improve overall patient outcome. "The program could be lucrative if the correct protocol is identified."

Shrader, however, said the inconvenience caused by frequent dosing may limit the potential market size, but added that this could be partially offset by increased cost of therapy.

Dysmenorrhea, which is characterized by recurrent uterine cramping and pain before and during menses, affects 12 percent of all menstruating women in the United States between the ages of 20 and 45, or about 5.6 million women, according to the company.

Shares of Columbia, based in Livingston, New Jersey, were down 90 cents at $2.56 in afternoon trade on Nasdaq. They touched a low of $2.15 earlier in the session. (Editing by Himani Sarkar)