Novel vaginal film for birth control impresses in early-phase trial

Applying a single dose of the novel vaginal film ZB-06 before intercourse is safe and appears to prevent sperm from reaching the egg, according to the results of a phase I, proof-of-concept trial.

ZB-06 is a vaginal film that contains HC4-N, a human contraceptive antibody that inactivates sperm. In the present trial, researchers looked at the potential contraceptive activity of the ZB-06 film using a surrogate assessment for contraceptive efficacy, the postcoital test. Safety was also assessed.

Additionally, serum, cervical mucus, and vaginal fluid HC4-N antibody concentrations, and sperm agglutination potency were measured after single film use. Changes in the concentration of soluble proinflammatory cytokines and vaginal Nugent score after film use were also determined as subclinical safety endpoints.

The trial included 20 healthy women, with eight heterosexual couples completing all study visits. The film was safe for both the women and their male sexual partners. In the postcoital test conducted on ovulatory cervical mucus at baseline (no product use), a mean of 25.9 progressively motile sperm per high-power field was found. This number significantly dropped to 0.04 progressively motile sperm per high-power field after a single application of the ZB-06 film before intercourse (p<0.0001).

At the follow-up postcoital test visit approximately 1 month later (no product use), a mean of 47.4 (±37.4) progressively motile sperm per high-power field was observed, indicating contraceptive reversibility.

The present data highlight the potential of ZB-06 as a contraceptive, warranting further development and testing, according to the researchers.