The efficacy and safety of testosterone undecanoate (nebido®) in testosterone deficiency syndrome in Korean: A multicenter prospective study

Introduction.: Long-acting injectable testosterone undecanoate (TU, Nebido^®), a new parenteral testosterone preparation, has recently been introduced to avoid frequent injections of the conventional injectable esters. Aims.: To assess the efficacy and safety of long-acting injectable testosterone undecanoate (TU, Nebido^®) in Korean patients with testosterone deficiency syndrome (TDS). Methods.: One hundred thirty-three patients who complain of erectile dysfunction with serum testosterone level less than 3.5 ng/mL were injected with 1,000 mg of TU (4 mL/ample) on day 1, followed by another injection after 6 weeks and 18 weeks. For the safety profiles, serum hemoglobin (Hb), hematocrit (Hct), glucose, lipid profile, and prostate-specific antigen (PSA) were measured. Main Outcome Measures.: Body mass index (BMI) was measured at the time of the first visit and after 12, 24 weeks. Primary efficacy was evaluated according to changes in the International Index of Erectile Function (IIEF) from the initial visit to the final visit (24 weeks) and from the initial visit to each visit. Secondary efficacy was assessed with changes of the Aging Males' Symptoms (AMS) Scale and the Global Efficacy Question (GEQ) for improvement of erectile function. Results.: Mean age of patients was 54 ± 9.6 years. Compared with pretreatment, no significant improvement in BMI was observed. Serum total testosterone and free testosterone were significantly increased at 12 weeks and were maintained until 24 weeks (P < 0.001). TU significantly decreased cholesterol (P < 0.0001). TU significantly improved total IIEF, all five domain scores of IIEF (P < 0.0001) and total AMS, all three domain scores of AMS (P < 0.0001). On GEQ, TU improved erectile function in 76.9% of subjects. On safety profile, TU significantly elevated Hb, Hct, and PSA at 24 weeks but within normal range. No serious adverse reactions were observed. Drop-out rate was 15.0%. Conclusions.: In this prospective multicenter study, TU was effective, safe, and tolerable until 24 weeks in Korean TDS patients. Further well-controlled, long-term study should follow.