Unacceptable side-effects associated with a hyperosmolar vaginal microbicide in a phase 1 trial

Area of Science:

• Reproductive Health
• Infectious Disease Prevention
• Biomaterials Science

Background:

• Development of effective vaginal microbicides is crucial for HIV-1 prevention.
• Previous microbicide candidates have faced challenges with safety and efficacy.
• Cellulose acetate phthalate was investigated as a potential microbicide agent.

Purpose of the Study:

• To evaluate the safety and tolerability of a novel vaginal microbicide gel in a phase 1 clinical trial.
• To identify potential adverse effects associated with the candidate microbicide formulation.
• To investigate the biophysical properties of the microbicide gel and their impact on vaginal mucosa.

Main Methods:

• A phase 1 clinical trial was conducted with women participants.
• The candidate microbicide gel contained cellulose acetate phthalate in a glycerol-based vehicle.
• Post-termination investigations included analysis of gel osmolality and rheology.

Main Results:

• The study was terminated prematurely due to unacceptable vulvo-vaginal side effects in all participants.
• High osmolality of the gel was identified as the likely cause of excessive fluid transudation and mucosal dysfunction.
• Significant changes in gel rheology upon fluid dilution were observed.

Conclusions:

• The candidate vaginal microbicide gel formulation was not well-tolerated due to its high osmolality.
• Early analysis of osmolality and rheology is critical for the development of safe and effective genital mucosal products.
• Further research is needed to develop microbicides with improved safety profiles.