GTx reports top line results from toremifene Phase III clinical trial for prostate cancer

GTx, Inc. (Nasdaq: GTXI) today announced top line results of the Phase III clinical trial evaluating toremifene 20 mg, a selective estrogen receptor modulator, for the prevention of prostate cancer in men with high grade prostatic intraepithelial neoplasia, or PIN, a premalignant lesion of the prostate.

“GTx and Ipsen will pursue their partnership to develop toremifene 80 mg and are planning a second Phase III clinical trial evaluating toremifene 80 mg to reduce fractures and treat other estrogen deficiency side effects of androgen deprivation therapy for prostate cancer.”

Incidence of prostate cancer was lower in men receiving toremifene 20 mg compared to placebo but not statistically significantly different.

GTx randomized 1,590 men with high grade PIN into the three year clinical trial. In the study, there were no clinically significant differences in the adverse event safety profile between men treated with toremifene 20 mg and men receiving placebo. Venous thromboembolic events were similar among men receiving placebo and men taking toremifene 20 mg. Cardiovascular adverse events were also similar between the two study arms.

"We designed the Phase III trial based upon the successful outcome of our Phase IIb clinical trial. Toremifene 20 mg did also reduce prostate cancer in our Phase III study but based on our review of the topline data, there is not a sufficient reduction in cancers compared to placebo over a three year period to demonstrate the statistical significance required for this study," said Dr. Mitchell S. Steiner, CEO of GTx. "We intend to review all data from the study this summer to better understand the trial results and the ability of toremifene 20 mg to reduce cancer among these high risk men.

"We are grateful to the nearly 1,600 men with high grade PIN and the hundreds of physicians and site coordinators who participated in this clinical trial," Steiner said. "The study demonstrated that these patients are indeed at high risk for prostate cancer, with 45.5% of men in the placebo group developing prostate cancer within three years."

Steiner continued: "GTx and Ipsen will pursue their partnership to develop toremifene 80 mg and are planning a second Phase III clinical trial evaluating toremifene 80 mg to reduce fractures and treat other estrogen deficiency side effects of androgen deprivation therapy for prostate cancer."

GTx has submitted to FDA a protocol for the second toremifene 80 mg Phase III clinical trial and will meet with FDA this summer to finalize the trial design. GTx has secured funding for this clinical study through the expansion of its partnership with Ipsen which was announced March 23, 2010. GTx expects to initiate the TREAT 2 (Toremifene for Reduction of fractures and other Estrogen deficiency side effects in men on Androgen deprivation Therapy) Phase III clinical trial by year end 2010.

GTx is continuing to develop its pipeline of product candidates to address unmet medical needs. In addition to advancing toremifene 80 mg in the second Phase III clinical trial, GTx is expecting results of the Phase II clinical trial evaluating GTx-758, an oral LH inhibitor for first line treatment of advanced prostate cancer this summer and is planning late stage clinical trials for Ostarine™ (GTx-024) for the prevention and treatment of cancer induced muscle wasting (cancer cachexia).