Comparison of the Safety and Efficacy of a Novel Long Acting Formulation of Testosterone Undecanoate with Testosterone Enanthate in Hypogonadal Men

Minnemann, T⁽¹⁾; Saad, F^{(2, 3)}; Schubert, M⁽¹⁾; Hübler, D⁽⁴⁾; Rouskova, D⁽⁴⁾; Gouni-Berthold, I⁽¹⁾; Schumann, C⁽¹⁾; Christoph, A⁽¹⁾; Oettel, M⁽⁴⁾; Ernst, M⁽⁴⁾; Mellinger, U⁽⁴⁾; Krone, W⁽¹⁾; Gooren, L⁽⁵⁾; Jockenhövel, F⁽⁶⁾

⁽¹⁾Klinikum der Universität zu Köln, Köln, Germany ⁽²⁾Male Healthcare, Bayer Schering Pharma, Berlin, Germany ⁽³⁾Research Dept., Gulf Medical College School of Medicine, Ajman/UAE ⁽⁴⁾Jenapharm, Jena, Germany ⁽⁵⁾Vumc, Amsterdam, Netherlands ⁽⁶⁾Evangelisches Krankenhaus, Herne, Germany

Objective: To compare the safety and efficacy of a novel long-acting intra-muscular testosterone undecanoate (TU) formulation with testosterone enanthate in hypogonadal men. Methods: This was an open-label, randomized, prospective study involving 40 hypogonadal men (testosterone levels <5 nmol/L), administered either 250 mg testosterone enanthate (TE) i.m. every 3 weeks (n=20) or 1000 mg TU i.m. every 6-9 weeks (n=20), for 30 weeks. At the end of the study period, 36 patients continued in an open-label single arm follow-up study, where they received 1000 mg TU i.m. every 12 weeks, for a further 114 weeks. Levels of testosterone, leptin, lipids, PSA and hemoglobin were measured, together with hematocrit, grip strength and BMI at weeks 30 and at regular intervals throughout the single arm follow up. Results: The levels of testosterone achieved in the initial 30 week study have previously been reported (Schubert M et al. J Clin Endocrinol Metab 2004 89 5429-34). In the follow up study, levels of testosterone were above the lower limit of reference values, immediately prior to each 12-week injection of TU. In additon, both TU and TE produced statistically significant improvements in grip strength in the initial 30 week study, which continued when all subject received TU in the follow up. Beneficial effects on leptin, total cholesterol, LDL-cholesterol, HDL-cholesterol and triglycerides were observed with both TU and TE in the initial 30 week study, and in the follow up period with TU. Hematocrit and levels of PSA and hemoglobin rose slightly on both TU and TE in the first 30 weeks, with a further increase observed over the first 12 months, but then remaining stable and within the normal range, during the TU follow up. Conclusions: Administration of TU every 12 weeks provides adequate long-term testosterone replacement, with a similar safety and efficacy profile to TE. TU offers an alternative for testosterone therapy in hypogonadal men with a lower injection frequency.