GTx, Inc. (Nasdaq: GTXI) today presented a safety analysis demonstrating that fewer men treated with toremifene 80 mg had PSA progression over time compared to placebo in the Phase III clinical trial evaluating toremifene 80 mg for the treatment of multiple serious side effects of androgen deprivation therapy (ADT) for advanced prostate cancer. These data, as well as an additional analysis of bone turnover markers and fracture risk, were presented at the 2008 Annual Meeting of the American Society for Bone and Mineral Research in Montreal, Canada.

Among men in the intent-to-treat population with a detectable PSA (PSA ≥ 1 ng/ml) at baseline (n=419), significantly fewer men treated with toremifene 80 mg had PSA progression over time compared to men taking placebo (27% versus 37%, respectively; p < 0.05). This subgroup analysis is consistent with the recommendations of the Prostate Cancer Clinical Trials Working Group to measure prostate cancer progression in clinical studies. In another analysis among men with an undetectable PSA (PSA < 1 ng/ml) at baseline (n= 698), there was no difference in PSA progression in men treated with toremifene 80 mg compared to men taking placebo.

“These new safety data are consistent with the mechanism of action observed in other studies evaluating toremifene, which have demonstrated inhibition of prostate growth in animal models, as well as in our Phase IIb clinical trial evaluating toremifene for the prevention of prostate cancer,” said Mitchell S. Steiner, MD, Chief Executive Officer of GTx.

“In men with advanced prostate cancer, PSA is a sensitive marker of progression and is followed closely by physicians and patients to monitor the underlying cancer,” Dr. Steiner continued. “It is encouraging to find that in our Phase III clinical trial in men with advanced prostate cancer on ADT, who have castrate levels of testosterone and estrogen, toremifene 80 mg treatment resulted in fewer men with detectable PSA at baseline demonstrating PSA progression over time when compared to placebo.”

Additional data from the study were also highlighted during the presentation. An efficacy analysis studied changes in three serum markers of bone turnover: C-telopeptides, bone specific alkaline phosphatase (bALP), and osteocalcin. Changes in the three markers were further evaluated among men in the trial who experienced a new morphometric vertebral fracture.