GTx commences Capesaris Phase IIb trial in advanced prostate cancer

GTx, Inc. (Nasdaq: GTXI), announced today that it initiated a Phase IIb clinical trial evaluating Capesaris™, a selective estrogen receptor alpha agonist, compared to Lupron Depot® (leuprolide acetate for depot suspension) for first line treatment of advanced prostate cancer.

"Acting selectively through estrogen receptor α, Capesaris has the potential to achieve medical castration without also causing several well documented problems of androgen deprivation therapy for prostate cancer such as hot flashes, bone loss and metabolic syndrome," said Thomas Keane, MD, Chairman and Professor of Urology at the Medical University of South Carolina, and lead investigator of the multicenter Capesaris Phase IIb clinical trial. "A new form of first line hormonal treatment that avoids some of the side effects of current ADT would be an important development."

"We are excited to have initiated the Phase IIb Capesaris clinical trial," said Ronald A. Morton, Jr., M.D., Chief Medical Officer of GTx. "Because of the tremendous interest to find a better ADT, we expect this trial to enroll quickly and to have primary efficacy results from the study in the fourth quarter 2011."

The Phase IIb clinical trial is an open label study comparing oral Capesaris tablets to Lupron Depot®, a luteinizing hormone releasing hormone (LHRH) agonist. One hundred and fifty-six men with advanced prostate cancer will be randomized to receive one of two doses of Capesaris (2000 mg orally each day or 1000 mg orally each day) or Lupron Depot® injection every 3 months. The purpose of this study is to establish the dose of Capesaris required to maintain medical castration. The primary endpoint of the study is the proportion of patients that achieve castration by day 60. Secondary endpoints include maintenance of castration beyond 60 days, levels of free testosterone, sex hormone binding globulin (SHBG), luteinizing hormone, and prostate specific antigen (PSA), as well as safety endpoints of Capesaris compared to leuprolide such as hot flashes, libido changes, lipid profile, body composition, bone turnover markers, and bone mineral density.

"Now that we have an oral tablet that has been shown to achieve medical castration, the next step is to conduct dose finding studies to select the appropriate loading and maintenance doses to advance into Phase III clinical trials," said Mitchell Steiner, MD, Chief Executive Officer of GTx. "This Phase IIb clinical trial will help us answer the question of finding the lowest effective dose to maintain castration and to assess the clinical impact of avoiding estrogen deficiency by measuring the safety endpoints compared to Lupron."

GTx plans to initiate an additional Phase II study in advanced prostate cancer patients in second half of 2011 to determine the loading dose of Capesaris required to achieve medical castration in greater than 90% of patients within 28 days. In addition, GTx plans to advance Capesaris into a Phase II study for second line therapy for patients with castration resistant prostate cancer who have failed LHRH therapy.

Source: GTx, Inc.