GTx, Inc. (Nasdaq: GTXI) announced today there will be a presentation on the mechanism of action of Capesaris® to induce sex hormone binding globulin (SHBG) and subsequently reduce free testosterone (FT) in men with castration resistant prostate cancer. On September 29, 2012, between 1:00 and 2:00pm Vienna time, at the European Society for Medical Oncology (ESMO) 2012 to be held in Vienna, Austria from September 28 through October 2, 2012, GTx will make a presentation entitled: “GTx-758, an Oral ERα Agonist, Increases Sex Hormone Binding Globulin, Reduces Free T and Decreases PSA in Patients With Castration Resistant Prostate Cancer.”
Mitchell S. Steiner, MD, Vice-Chairman and CEO of GTx, will present data from the company’s Phase II G200707 clinical study of Capesaris providing evidence that Capesaris increases SHBG, decreases FT, and reduces serum PSA. In another recent Phase II clinical study conducted by GTx (G200705) in men with advanced prostate cancer who were hormone naïve, a significant reduction in FT was observed in Capesaris treated subjects in comparison to those treated with Lupron®, a LHRH agonist for the treatment of advance prostate cancer. The Phase II clinical studies were stopped early due to an increased risk of venous thromboembolic events (VTEs) at the higher Capesaris doses used in these previous clinical studies. However, clinical data from Phase I and Phase II studies suggest that significant increases in serum SHBG, and corresponding reductions in FT, can be achieved with lower (125 to 500 mg) doses of Capesaris.
GTx has initiated a new Phase II clinical trial (G200712) to evaluate the safety and effectiveness of lower doses of Capesaris to treat men with metastatic castration resistant prostate cancer. Seventy-five men with metastatic castration resistant prostate cancer will be randomized into one of three cohorts to receive a 125 mg, 250 mg or 500 mg daily dose of Capesaris. Each arm will have 25 subjects and the enrollment will be conducted sequentially, with the 125 mg cohort being the first to be enrolled. The enrollment into the next higher dose of Capesaris will commence if an acceptable incidence of VTEs is observed among randomized patients for 30 days following enrollment of the last patient in the previous cohort. The primary endpoint will be to lower serum PSA by ≥ 50% by day 90. Other key cancer endpoints include serum PSA progression, time to progression and progression free survival in these study subjects. In addition, the study will evaluate the ability of Capesaris to treat certain estrogen deficiency side effects associated with medical castration such as hot flashes, bone loss, and insulin resistance.