GTx, Inc. (Nasdaq: GTXI) announced today that in a Phase IIb clinical study of enobosarm, there was significantly improved physical function after 16 weeks of treatment, compared to placebo, in both hypogonadal (low testosterone) and eugonadal (normal testosterone) subjects. The study met its primary endpoint of absolute change in total lean body mass (muscle) compared to placebo after 16 weeks of treatment. The data were reported by Adrian Dobs, M.D., M.H.S., professor of medicine and oncology, and Vice-Chair of the Department of Medicine, Faculty Development at The Johns Hopkins University Medical School, during the 2012 Annual Meeting of The Endocrine Society (ENDO 2012). Enobosarm is currently being evaluated in two pivotal Phase III clinical trials.
In the presentation, “Prevalence and Impact of Hypogonadism in Cancer Patients with Muscle Wasting in a Phase IIb Enobosarm Trial,” Dr. Dobs reported that enobosarm, a selective androgen receptor modulator (SARM), may play an important role in the management of cancer-related muscle wasting. When correlating baseline testosterone levels with weight loss, hypogonadal male subjects in GTx’s Phase IIb clinical study of enobosarm demonstrated greater weight loss than eugonadal males. Dr. Dobs noted that baseline physical function (stair climb power) of subjects in the study was higher among eugonadal versus hypogonadal males.
In the Phase IIb clinical study of enobosarm, 159 subjects were randomized to enobosarm or placebo for 16 weeks. The subjects were males greater than 45 years of age and postmenopausal females who had non-small cell lung cancer, colorectal cancer, non-Hodgkin’s lymphoma, chronic lymphocytic leukemia or breast cancer and experienced a 2% or greater weight loss during the 6 months prior to the study’s initiation. Of the 103 male subjects in the study, baseline testosterone levels were available for 93 men. 60% of the males were found to be hypogonadal at randomization, and the distribution of hypogonadism was similar across all forms of the cancers.