Safety and Pharmacokinetics of PSD502 in Healthy Chinese Male and Female Volunteers: Two Randomized, Double-Blind, Placebo-Controlled, Phase I Trials

Background and Objective PSD502 is a metered-dose spray for premature ejaculation. The two trials aimed to evaluate the safety and pharmacokinetics of PSD502 in healthy Chinese male and female individuals. Methods Two phase I, randomized, double-blind, placebo-controlled trials were conducted in men (Trial 1) and women (Trial 2). The participants were randomized 3:1 to receive PSD502 (7.5 mg of lidocaine and 2.5 mg of prilocaine per spray) or a placebo. For male individuals, a single dose (three sprays) once daily was applied to the glans penis for 21 days except for nine sprays (three doses) on days 7 and 14, 4 h apart for each dose. For female individuals, two sprays were applied to the vagina and one to the cervix once daily for 7 days. The primary endpoint was safety. Pharmacokinetics analysis was also performed. Results Twenty-four male and 24 female individuals were recruited. Treatment-emergent adverse events occurred in 38.9% (7/18) of male individuals and 66.7% (12/18) of female individuals in the PSD502 group, respectively. Both trials reported 50.0% (3/6) treatment-emergent adverse events for the placebo. No grade ≥ 3 treatment-emergent adverse events, serious adverse events, or treatment-emergent adverse events leading to early withdrawal or discontinuation occurred. After consecutive applications, lidocaine and prilocaine cleared rapidly in both trials. Plasma concentrations exhibited high inter-individual variability. The maximum plasma concentrations of active ingredients were far below the anticipated minimum toxic concentrations. The area under the plasma concentration–time curve of metabolites were ≤ 20% of the parent drugs. No clinically significant accumulations were observed in the two trials. Conclusions PSD502 was well tolerated and showed low plasma concentrations in healthy Chinese male and female individuals.