Male contraceptive stops sperm's 'ability to swim' — without side effects, UNC study says

Birth control pills in their calendar dispensing packaging.
Birth control pills in their calendar dispensing packaging. TNS

University of North Carolina and Oregon State scientists showed in preclinical trials that a new form of male contraceptive can immobilize sperm temporarily without side effects.

A new study published Thursday in the journal "PLOS ONE" explains how a compound called EP055 binds to sperm to significantly slow the overall mobility of the sperm without affecting hormones, making EP055 a potential "male pill" without side effects.

"Simply put, the compound turns off the sperm's ability to swim, significantly limiting fertilization capabilities," said lead investigator Michael O'Rand, retired professor of cell biology and physiology at the UNC School of Medicine, and president/CEO of Eppin Pharma, Inc. "This makes EP055 an ideal candidate for non-hormonal male contraception."

The only safe forms of birth control available for men on the current market are condoms and surgical vasectomy (which can be reversible). There are hormonal drugs in clinical trials that target the production of sperm, but those developed so far usually affect the natural hormones in men, like female contraceptives affect hormones in women.

During the study, male rhesus macaques — a type of monkey — were given a high-dose intravenous infusion. Thirty hours after the dose, researchers saw no indication of normal sperm motility. Further, no physical side effects were observed.

"At 18 days post-infusion, all macaques showed signs of complete recovery, suggesting that the EP055 compound is indeed reversible," said study co-investigator Mary Zelinski, in a news release. Zelinski is also a research associate professor at the Oregon National Primate Research Center at Oregon Health and Science University, and an associate professor of obstetrics and gynecology at the OHSU School of Medicine.

Researchers said more work is needed before EP055 becomes available for human use, but the teams have begun to test a pill form of the compound and will eventually conduct a mating trial to determine its effectiveness against pregnancy.