Testosterone Replacement Therapy: A Narrative Review with a Focus on New Oral Formulations

Abstract

Male hypogonadism affects 10-30% of the male population and is often under-recognized and under-treated. Different replacement formulations exist, each with specific benefits and limitations. These replacements include gels, patches and short- and long-acting injectables. JATENZO® (oral testosterone undecanoate; Clarus Therapeutics Inc., Northbrook, IL, US) is the first oral formulation of testosterone approved by the US Food and Drug Administration. TLANDO® (oral testosterone undecanoate; Lipocine Inc., Salt Lake City, UT, US), another oral testosterone formulation, has also recently been approved by the US Food and Drug Administration. Based on unique chemistry using a self-emulsifying drug delivery system and lymphatic absorption, JATENZO and TLANDO address some of the limitations of other dosing routes while providing a safe option without evidence of liver dysfunction. This review discusses various testosterone treatment options, focusing on the role and pharmacokinetics of the new oral formulations.

Keywords: JATENZO; TLANDO; male hypogonadism; oral testosterone replacement; self-emulsifying drug delivery systems; testosterone replacement therapy; testosterone undecanoate.

Figure 1:. Components of self-emulsifying drug delivery systems

Figure 2:. Micellar uptake of hydrophobic drug

Figure 3:. Lymphatic transportation of the hydrophobic drug in the lymphatic system

Figure 4:. Plot of mean (± standard error) Na F-EDTA measured serum testosterone concentration versus time after dosing at the end of 24 days of therapy with twice-daily dosing of JATENZO in 151 subjects at different titration visits

Figure 5:. Plot of mean (± standard error) serum testosterone concentration versus time after dosing at the end of 24 days of therapy with fixed dose 225 mg twice daily of TLANDO in 90 subjects