Vaginal ring for sustained release of lactic acid to prevent bacterial vaginosis and associated health risks

项目总结

Project Summary Millions of women in the U.S. suffer from bacterial vaginosis (BV), a vaginal condition initiated by marked overgrowth of polymicrobial bacterial populations that can suppress protective lactobacilli. Healthy lactobacilli secrete lactic acid (LA) that acidifies the vagina and acts as a broad-spectrum microbicide that protects against many types of pathogens and also can suppress polymicrobial communities of BV species that produce little or no lactic acid. We do not know what initiates episodes of BV, but we do know that BV strongly increases risks of many sexually transmitted infections including HIV, and increases risks of premature births. At any given time, about 1/3 of sexually active women in the U.S. and world-wide have BV. Antibiotics can provide transient relief from the foul-smelling discharge caused by BV but they do not prevent BV from recurring (sometimes at a frequency up to twice a month). There is no product on the market that can provide sustained protection against BV. We and others have shown that LA can potently inactivate many types of BV- associated bacteria as well as many types of pathogens that cause sexually transmitted infections. Since LA is abundant in the healthy vaginas of women with protective lactobacilli, it has the potential to provide a safe nontoxic microbicide. We have recently determined the rate at which healthy lactobacilli continuously produce LA and hence for the first time know the rate at which lactic acid should be supplied to the vagina to treat and prevent BV. This has enabled us to develop an LA-releasing intravaginal ring (LA-IVR) that can provide sustained release of LA over 30 days at the rate needed to treat and prevent BV while not suppressing healthy lactobacilli. Through careful selection of polymers and formulation design, we have shown that we can tune the release rates of LA from various polymeric matrices, and achieve sustained release of LA. Building on our promising pilot work, we seek in Aim 1 to optimize our lead LA-IVR formulation, and perform various characterizations including LA release rates over time, hydrophobicity, and mechanical properties (elasticity, compressibility). We will then fabricate a macaque LA-IVR, and in Aim 2 test whether sustained release of LA by this IVR can suppress BV-like bacterial species in pigtail macaques. Successful demonstration of safety and efficacy in this highly relevant large animal model would support advancing Mucommune’s LA-IVR through IND-enabling activities. The simplicity of our LA-IVR design ensures both ease of production and likely very low manufacturing costs of the eventual product, which in turn should maximize potential public health impact and commercial viability of the product both in the U.S. and in low and middle income countries worldwide. (26 lines)