Phase 1 evaluation of the safety, acceptability, and pharmacokinetic profile of an OB-002H gel


BACKGROUND: OB-002 is an extremely potent CCR5 antagonist that has previously been shown to completely block vaginal transmission of a SHIV virus (SF162P3) in a non-human primate model of HIV infection (Veazey R et al. JID 2009). The purpose of this study was to characterize the safety, acceptability, and systemic absorption of a gel formulation of OB-002 (OB-002H).
METHODS: The trial had two phases, an open label single dose exposure (vaginal and rectal) and a randomized placebo controlled multiple dose phase during which study participants received five vaginal daily doses of OB-002H gel or matched placebo in a 2:1 ratio. The first three participants in the multiple dose phase of the study received open label OB-002H gel. All gel administration was performed by medical staff. Serum OB-002 levels were quantified at multiple time points up to 24 hours after the first dose. Participants also completed a product acceptability questionnaire after the final dose of gel.
RESULTS: A total of 30 participants were enrolled in the study. Twelve participants were enrolled in the single dose phase of the study (six in the vaginal and six in the rectal administration arms of the study), three participants were enrolled in the open label multiple vaginal dose phase, and fifteen participants in the randomized phase of the study. Only two product related transient Grade 2 events (both vulval dryness) occurred in the study, both were in the OB-002H gel randomized multiple dose arm. All colposcopic and anoscopic assessments were normal. There was no evidence of systemic absorption of OB-002. Overall, the product had a positive acceptability profile, and most study participants would consider using the product for protection against HIV or pregnancy.
CONCLUSIONS: OB-002H gel was safe and well tolerated with a good acceptability profile and high intentionality of future use. Future studies are needed to assess the extended safety and acceptability of the product in sexually active participants.