Efficacy of kallikrein in the treatment of oligozoospermia and asthenozoospermia: A double-blind trial

Objective: To assess the effect of kallikrein on sperm motility and sperm count in infertile oligozoospermic and asthenozoospermic men. Design: Double- blind placebo-controlled clinical trial. Setting: Multicenter trial in three andrologic clinics. Patients: Infertile men with <20 x 10⁶ total sperm count and >3 x 10⁶ sperm cells/mL and/or sperm motility of <30%. Interventions: One hundred fourteen men received either placebo or 600 kallikrein units of kallidinogenase by mouth daily for 12 weeks. Semen analyses were performed before and at 6-week intervals during the trial. Compliance and incidence of adverse effects were assessed. Results: The incidence of adverse effects was similar under placebo and under kallidinogenase treatment, usually mild, transient, and did not require the cessation of treatment in any patient. Kallidinogenase was not superior to placebo in improving sperm count and sperm motility. Conclusions: At the doses and for the duration given, our results were disappointing. The absence of a therapeutical effect, as evidenced in the present study may be due to the very low absorption rate of kallidinogenase after oral administration. Probably a much higher dose of kallidinogenase should be used to achieve a therapeutic affect.