Zero sperm production is not the goal. Lowering it sufficiently is
Dr. Thirumalai said the need for a male contraceptive is strong. While condoms have a substantial failure rate, vasectomy is not reliably reversible even though the majority of men agree that the responsibility for preventing pregnancy should be shared, she said.
Dr. Thirumalai’s earlier review article found that clinical trials of hormonal suppression to provide male contraception have been conducted for at least 30 years. The challenge has been finding an effective therapy that is well tolerated.
Drugs that combine both androgenic and progestogenic activity might be the answer. By manipulating hormones that lower testosterone, sperm production is reduced without eliminating a man’s ability to ejaculate. Zero sperm production is not the goal, according to data in Dr. Thirumalai’s review article.
Rather, studies suggest that when ejaculate contains less than 1 million sperm per mL (levels typically range from 15 to 200 million sperm/mL), the antipregnancy efficacy is similar to that achieved with female oral contraceptives.
However, clinical trials to demonstrate that this can be achieved safely have yet to be conducted.
Ms. Jacobsohn said that sperm half-life is about 3 months. This means that patients would need to be on hormonal therapy for a period of about this duration before reliable contraception is achieved.
In other words, the efficacy endpoint used in this current study [of 28 days duration] does not ensure effective contraception, but Ms. Jacobsohn suggested this is nevertheless an important step forward in clinical development.
Ms. Jacobsohn and Dr. Thirumalai report no relevant financial relationships.
A version of this article first appeared on Medscape.com .