A novel testosterone gel formulation normalizes androgen levels in hypogonadal men, with improvements in body composition and sexual function

OBJECTIVE To compare the safety and efficacy of two doses of a new testosterone gel formulation (Testim(TM), Auxilium Pharmaceuticals, Inc., Norristown, PA, USA) to a permeation-enhanced testosterone patch (Andropatch(R), GlaxoSmithKline, UK) for treating men with confirmed low serum testosterone levels, and associated signs and symptoms of hypogonadism. PATIENTS AND METHODS In all, 208 men were randomized and treated at 29 centres in Denmark, Germany, Netherlands, Sweden and the UK. The men were treated for 90 days, and the pharmacokinetics and treatment effectiveness of Testim at two doses (50 and 100 mg/day, delivering a daily dose of 5 and 10 mg testosterone, respectively) and Andropatch (2 x 2.5 mg patches, each delivering 2.5 mg testosterone and containing 12.2 mg of testosterone) were compared. Pharmacokinetic profiles were obtained, body composition measured, and mood and sexual function data recorded. RESULTS Testim produced dose-dependent improvements in all pharmacokinetic variables compared with Andropatch. The mean increases from baseline to 90 days in testosterone were 12.41, 6.54 and 3.82 nmol/L for Testim 100 and 50 mg/day and the Andropatch, respectively. Both doses of Testim significantly improved positive and negative mood over baseline; Andropatch did not. All three treatments increased lean body mass, and the higher dose of Testim produced a significant decrease in percentage body fat. At all sample times both doses of Testim significantly improved sexual performance, sexual motivation, sexual desire and spontaneous erections. Andropatch provided insignificant improvements from baseline at all sample times for sexual desire, an inconsistent improvement in sexual motivation, but no effect on spontaneous erections. These results are similar to those previously reported for testosterone replacement therapy in hypogonadal men, suggesting that normalization of serum testosterone restores sexual function. However, the present data suggest that higher serum testosterone levels may further improve sexual function. Gel treatment was well tolerated, while patch treatment produced higher rates of application-site reactions and study discontinuation. CONCLUSION The favourable pharmacokinetic profile and treatment outcome, combined with the enhanced tolerability of Testim, suggest that this new gel formulation is a safe and effective treatment in men with low serum testosterone levels and associated signs and symptoms of hypogonadism.