Topical contraceptive safely, effectively immobilizes sperm
Healio News – by Richard Gawel
An anti-sperm monoclonal antibody has been found to be safe and possess potent sperm agglutination, or clumping, and immobilization activity in laboratory tests, according to a study published by EBioMedicine.
Researchers from the Boston University School of Medicine (BUSM) and ZabBio — a company that develops monoclonal antibodies to address infectious diseases and reproductive health, according to its website — said the human contraception antibody (HCA) could be administered vaginally in a dissolvable film for a woman-controlled, on-demand birth control method.
The researchers said they tested HCA over a wide range of concentrations and under different physiologically relevant conditions in vitro to evaluate its suitability as a topical contraceptive, mixing it with sperm from healthy volunteers. Semen samples used all met WHO fertile semen parameters.
Within 15 seconds, the researchers said, sperm became immobilized and firmly stuck together. Also, HCA did not cause vaginal inflammation in lab tissue culture tests. Due to its effectiveness and safety profile, the researchers said, HCA may address current gaps in contraception.
“We anticipate that our product will be as effective as other pericoital methods such as N-9 or Phexxi and will have the advantage of providing protection for at least 4 hours. N-9 and Phexxi are only good for 1 hour,” study researcher Deborah J. Anderson, PhD, a professor of medicine at BUSM, told Healio.
The researchers also believe that HCA could be safely used by women who do not use other current contraceptive methods, with a significant impact on global health.
“Because our product is a human antibody, and such antibodies are naturally present, we do not expect any side effects,” Anderson said.
“We have not noted any adverse events in the clinical trial we have performed to date with the HCA vaginal film or with another related antibody product, MB-66, a combination of anti-HIV and [anti-herpes simplex virus (HSV)] monoclonal antibodies,” she continued.
The researchers hope HCA will be offered over the counter, with the antibody dose costing as little as 7 cents, Anderson said, although formulating, packaging, transport and sale will add to the cost. HCA is now being tested in a phase 1 clinical trial.
“Endpoints are safety, [pharmacokinetics (PK)] and a fertility surrogate test called the post-coital test, where the number of progressively motile sperm are counted in cervical mucus after intercourse,” Anderson said.
“We hope to conduct phase 2a studies (dose finding, more extensive PK) starting next year, and transition into phase 2/3 efficacy trials in 3 to 4 years,” she said.
The researchers also believe HCA could be combined with other antibodies, such as anti-HIV and anti-HSV antibodies, for a multipurpose prevention technology. It could then serve as a contraceptive and prevent sexually transmitted infections.
Full article available at: https://www.healio.com/news/womens-health-ob-gyn/20210806/topical-contraceptive-safely-effectively-immobilizes-sperm