In this analysis, the study met its primary endpoint of absolute change in total lean body mass (muscle) compared to placebo and the secondary endpoint of muscle function (performance) after 16 weeks of treatment. GTx plans to present complete study results in 2009.
The clinical trial enrolled 159 cancer patients (average age of 66 years) with non-small cell lung cancer, colorectal cancer, non-Hodgkin lymphoma, chronic lymphocytic leukemia, or breast cancer at 35 sites in the US and Argentina.
Participants were randomized to receive placebo, 1mg or 3mg oral capsule of Ostarine once daily for 16 weeks.
The primary endpoint of the study was lean body mass measured by dual energy X-ray absorptiometry (Dexa) scan. A prespecified analysis was comparison of treatment arms with placebo using the exact Wilcoxon rank sum test stratified by cancer type in patients with Dexa scans performed at baseline and at the end of the study. Topline results showed that Ostarine treatment resulted in a statistically significant increase in lean body mass compared to placebo.
Ostarine treatment resulted in clinically meaningful increases (greater than 1kg) in lean body mass compared to baseline in both the Ostarine 1mg and 3mg treatment arms. Topline results also showed that Ostarine treatment improved muscle function (performance) in a 12-step stair climb test measuring speed and calculating power, a secondary endpoint of the study. No improvement in speed or power was observed for the placebo group. There were no improvements in the endpoints of grip strength and gait speed.
Mitchell Steiner, CEO of GTx, said: We are excited that Ostarine met the primary endpoint of the Phase II cancer cachexia clinical trial. Even with the background of a heterogeneous cancer population, cancer induced inflammation, and chemotherapy, the changes compared to placebo in lean body mass and stair climb performance observed in this study are similar in magnitude to the changes observed in the earlier Ostarine Phase II proof of concept sarcopenia clinical trial. We are looking forward to continuing our work with Merck on the future development of Ostarine and other selective androgen receptor modulator (SARMs).
GTx and Merck & Co are collaborating to develop Ostarine and other SARMs, which are a new class of drugs with the potential to treat sarcopenia, which is the loss of skeletal muscle mass resulting in reduced physical strength and ability to perform activities of daily living, cancer cachexia and other musculoskeletal conditions.