Endocrine Abstracts

Objective: This open-label, single-arm study assessed the long-term safety and efficacy of injectable testosterone undecanoate (TU; Nebido) in men with hypogonadism.

Methods: Men aged 18–75 years with hypogonadism (baseline serum total testosterone <10 nmol/l) were recruited. The study was performed under conditions designed to resemble routine clinical management: patients with underlying conditions such as diabetes mellitus and hypertension were eligible for inclusion, and variable injection intervals were permitted. The study protocol was approved by the appropriate independent ethics committees. Patients received intramuscular injections of 1000 mg TU at treatment visits separated by intervals of 6–10 weeks (after the first injection) or 10–14 weeks (after all subsequent injections). Here, we report the findings of an analysis performed at the end of the interval following the tenth injection (1.8–2.6 years after patient entry into the study). The primary endpoint of the study was the serum level of prostate-specific antigen (PSA; assessed at baseline and at alternate treatment visits). Secondary variables included trough total testosterone levels (assessed at baseline and all treatment visits).

Results: A total of 77 patients (mean (standard deviation) age, 47.8 (11.6) years) were included in this analysis. Mean PSA levels remained close to baseline throughout (baseline: 0.81 (0.78) ng/ml; before ninth injection: 1.14 (1.1) ng/ml). Mean haematocrit remained with the normal range, and treatment was generally well tolerated. Trough total testosterone levels were restored to the physiological range after the second injection and throughout the remainder of the study (baseline: 5.8 (3.0) nmol/l; before tenth injection: 13.6 (3.7) nmol/l).

Conclusions: This ‘real-life’ study – performed under routine clinical conditions – confirmed the safety of long-term intramuscular TU treatment in men with hypogonadism. The efficacy of treatment in restoring and maintaining physiological levels of serum testosterone was also demonstrated.