UCLA

Background

A novel formulation of oral testosterone undecanoate (TU) was studied in a long- and short-term phase III trial to evaluate safety and efficacy.

Methods

Hypogonadal men (age 18-65 years; two morning serum testosterone (T) <300 ng/dl with signs/symptoms) were recruited into a 365 day (trial I) or 105 day (trial II), randomized, multicenter trial. Patients were randomized 1:1 to oral TU (n = 161) or T-gel (n = 160) in trial I, and 3:1 to oral TU, twice daily (BID) JATENZO® (n = 166) or a topical T product [Axiron® (n = 56)] in trial II. Dose adjustments were based on average T concentrations (Cavg). Efficacy was assessed based on T levels, body composition and bone density. Safety was assessed by standard clinical measures.

Results

Oral TU efficacy (% of patients with eugonadal T Cavg) was 84% (serum Cavg = 628 ± 343 ng/dl) and 87% (serum T equivalent Cavg ≈ 489 ± 155 ng/dl) in trials I and II, respectively. Oral TU significantly (p <0.0001) improved all Psychosexual Daily Questionnaire parameters in trials I and II. In trial I, lean mass increased 3.2 ± 2.7 kg and fat decreased by 2.4 ± 3.6 kg (both p <0.0001) and bone density improved in hip (+0.012 ± 0.0225 g/cm²) and spine (+0.018 ± 0.0422 g/cm²) after 365 days (both p <0.0001). Oral TU-associated adverse effects were consistent with other T-replacement therapies but oral TU patients experienced a greater number of mild gastrointestinal adverse effects. Oral TU subjects in both studies exhibited an increase in mean systolic blood pressure of about 3-5 mmHg. Oral TU was not associated with liver toxicity nor did it cause an elevation in high-sensitivity C-reactive protein or lipoprotein-associated phospholipase A₂ (cardiovascular safety biomarkers) after 365 days of therapy.

Conclusion

A new oral TU formulation was safe and effective and represents a significant therapeutic advance for the treatment of appropriate hypogonadal men.