(RTTNews) -  Monday, GTx, Inc. (GTXI: News ) said that it has received a complete response letter from the U.S. Food and Drug Administration, related to new drug application or NDA for toremifene 80 mg for the prevention of bone fractures in men with prostate cancer on androgen deprivation therapy. Following the news, the stock dropped more than 44% during the trading hours.

The FDA said that the data provided by GTx in its filing new drug candidate is insufficient. FDA also recommended the company for a second adequate and well controlled Phase III trial demonstrating the safety and efficacy of toremifene citrate 80mg. Further, the FDA sought an adequate and well-controlled clinical trial demonstrating that toremifene treatment to reduce fractures in men with prostate cancer on ADT does not have a detrimental effect on either time-to-disease progression or overall survival.

Memphis, Tennessee-based GTx said it has requested a meeting with the FDA to determine the appropriate next steps regarding the NDA.

Androgen deprivation therapy, or ADT, the main treatment for advanced prostate cancer, works by reducing testosterone levels by up to 95%. Testosterone is a primary growth factor of prostate cancer. However ADT also substantially depletes estrogen levels, the hormone responsible for bone quality and strength.

Depletion of estrogen can result in serious side effects, including a high risk of bone fractures, adverse lipid changes and increased risk of cardiovascular disease, as well as common symptomatic side effects such as growth of breast tissue often accompanied by tenderness and pain, and hot flashes.
GTx already markets toremifene 60 mg under the brand name Fareston for the treatment of advanced breast cancer in more than 60 countries including the U.S.

The company is also conducting a pivotal phase III clinical trial evaluating toremifene 20 mg for the prevention of prostate cancer in men with precancerous lesion called high grade prostatic intraepithelial neoplasia, or PIN. The primary endpoint of the study is a reduction in the incidence of prostate cancer. GTx plans to conduct the final analyses of the clinical trial following the conclusion of the study in the first-quarter of 2010.

In Monday's regular trading session, GTXI is currently trading at $4.90, down $4.08 or 45.43% on a volume of 4.43 million shares.

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by RTT Staff Writer

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