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In preclinical tests, researchers from UNC-Chapel Hill and Oregon Health and Sciences University showed how a new compound can immobilize sperm temporarily without side effects.

CHAPEL HILL, NC – A new study published today in the journal PLOS ONE details how a compound called EP055 binds to sperm proteins to significantly slow the overall motility 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, PhD, retired professor of cell biology and physiology in the University of North Carolina at Chapel Hill School of Medicine, and president/CEO of Eppin Pharma, Inc. “This makes EP055 an ideal candidate for non-hormonal male contraception.”

Currently, condoms and surgical vasectomy are the only safe forms of birth control currently available for men. There are hormonal drugs in clinical trials that target the production of sperm, but these affect the natural hormones in men much like female contraceptives affect hormones in women.

In 2001, O’Rand’s UNC School of Medicine lab published a paper in Gene about the discovery of the Eppin protein, which coats the entire sperm cell. They found this protein is crucial for the protection of the sperm. In 2009, O’Rand’s lab received an NIH grant to study compounds to inhibit the protein, and his team developed lead compounds that bound to Eppin.

When O’Rand retired in 2014 after 35 years in Taylor Hall, he formed Eppin Pharma Inc. with support from the UNC School of Medicine, Carolina Kickstart, and the North Carolina Biotechnology Center. The sole purpose of the company was to turn the compounds into a male contraceptive. He leased space – his old lab – from the UNC School of Medicine and continued working on developing the lead compounds. Four years later, the company is on the cusp of developing an effective pill version of the lead compound, EP055.

During this most recent study, his team showed that thirty hours following a high-dose intravenous infusion of EP055 in male rhesus macaques at the Oregon National Primate Research Center at OHSU in Portland, Oregon, researchers found 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, PhD, research associate professor at the ONPRC at OHSU and associate professor of obstetrics and gynecology in the OHSU School of Medicine.

O’Rand and Zelinski indicate that more work is needed before EP055 becomes available for human use. Their teams have begun to develop a pill form of the compound and will eventually conduct a mating trial of EP055’s effectiveness against pregnancy.

This study was funded by the National Institutes of Health, Eppin Pharma Inc., and, in part, by the North Carolina Biotechnology Center.