GTx Inc. initiates a proof of concept phase II clinical trial, designed to evaluate the ability of Ostarine, a selective androgen receptor modulator (SARM), to build muscle and to promote bone, as well as to assess its safety in both elderly men and postmenopausal women.

"We are excited about the progress of ostarine in clinical development," Mitchell S. Steiner, CEO of GTx said adding, "Ostarine was discovered by GTx scientists and is the first SARM to enter phase II clinical testing."

GTx believes that with unique, tissue selective anabolic activity, ostarine has the potential to distinguish itself from current osteoporosis drugs which only treat bone loss. In preclinical studies, ostarine not only strengthened bone by both building bone and preventing bone loss, but it also increased muscle. Greater muscle mass and strength help to prevent fall-related skeletal fractures by providing stronger support for bone and by improving a patient's balance and gait.

Ostarine had positive changes on muscle without clinically detectable side effects on the prostate or the skin.

"A positive outcome of this phase II ostarine clinical trial would distinguish ostarine from existing therapies for muscle and bone loss," said Steiner. "The clinical data will determine ostarine's novel anabolic effects and tissue selectivity. These data will support further development of ostarine for acute muscle wasting indications such as cancer, end stage renal disease, or burn injury wasting conditions, and for chronic indications such as osteoporosis and age related frailty," he added.

GTx is developing Acapodene (toremifene citrate), a selective estrogen receptor modulator, or SERM, in two separate clinical programs in men: first, a pivotal phase III clinical trial for the treatment of serious side effects of androgen deprivation therapy for advanced prostate cancer, and second, a pivotal phase III clinical trial for the prevention of prostate cancer in high risk men with high grade PIN.