Sarah George - Department of Reproductive Health
The landscape of women's birth control has remained largely unchanged for decades. Planned Parenthood's novel approach introduces topical films, similar to Listerine strips, administered vaginally to dissolve and release monoclonal antibodies produced in Nicotiana benthamiana. The MB66 film is a promising multipurpose prevention technology (MPT) designed to protect against HIV-1 and herpes simplex viruses (HSV-1 and HSV-2). A Phase I clinical trial evaluated its safety, pharmacokinetics, and efficacy. The study enrolled healthy, sexually abstinent women, divided into two segments. Segment A involved a single film insertion, while Segment B involved daily insertions for seven days, comparing active MB66 with a placebo.
Primary endpoints focused on adverse events (AEs), while secondary endpoints included film dissolution, vaginal health indicators, and antibody levels in vaginal fluids. Results showed that MB66 was generally safe and well tolerated, with no serious AEs reported. The most common AE was asymptomatic microscopic hematuria. There were no significant changes in vaginal pH, Nugent scores, or proinflammatory cytokines between active and placebo groups.
The trial demonstrated high acceptability and willingness to use the product. Antibody concentrations in vaginal secretions peaked at 1 hour post-dosing and remained elevated at 24 hours, providing significant neutralization of HIV-1 and HSV-2 ex vivo. However, further research is needed to assess the efficacy of MB66 in women at risk for these infections and explore adding antibodies for broader STI protection and contraception.
References:
Politch JA, Cu-Uvin S, Moench TR, et al. Safety, acceptability, and pharmacokinetics of a monoclonal antibody-based vaginal multipurpose prevention film (MB66): A Phase I randomized trial. PLoS Med. 2021;18(2):e1003495. Published 2021 Feb 3. doi:10.1371/journal.pmed.1003495
Edited By: Firas Batrash, Editor-in-Chief
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