title: Lack of prophylactic efficacy of oral maraviroc in macaques despite high drug concentrations in rectal tissues.
abstract: Maraviroc (MVC) is a potent CCR5 coreceptor antagonist that is in clinical testing for daily oral pre-exposure prophylaxis (PrEP) for HIV prevention. We used a macaque model consisting of weekly SHIV162p3 exposures to evaluate the efficacy of oral MVC in preventing rectal SHIV transmission. MVC dosing was informed by the pharmacokinetic profile seen in blood and rectal tissues and consisted of a human-equivalent dose given 24 h before virus exposure, followed by a booster postexposure dose. In rectal secretions, MVC peaked at 24 h (10,242 ng/ml) with concentrations at 48 h that were about 40 times those required to block SHIV infection of peripheral blood mononuclear cells (PBMCs) in vitro. Median MVC concentrations in rectal tissues at 24 h (1,404 ng/g) were 30 and 10 times those achieved in vaginal or lymphoid tissues, respectively. MVC significantly reduced macrophage inflammatory protein 1β-induced CCR5 internalization in rectal mononuclear cells, an indication of efficient binding to CCR5 in rectal lymphocytes. The half-life of CCR5-bound MVC in PBMCs was 2.6 days. Despite this favorable profile, 5/6 treated macaques were infected during five rectal SHIV exposures as were 3/4 controls. MVC treatment was associated with a significant increase in the percentage of CD3(+)/CCR5(+) cells in blood. We show that high and durable MVC concentrations in rectal tissues are not sufficient to prevent SHIV infection in macaques. The increases in CD3(+)/CCR5(+) cells seen during MVC treatment point to unique immunological effects of CCR5 inhibition by MVC. The implications of these immunological effects on PrEP with MVC require further evaluation.
authors.affiliation: Laboratory Branch, Division of HIV/AIDS Prevention, National Center for HIV, Hepatitis, STD, and Tuberculosis Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
authors.forename: Ivana
authors.initials: I
authors.lastname: Massud
authors.forename: Wutyi
authors.initials: W
authors.lastname: Aung
authors.forename: Amy
authors.initials: A
authors.lastname: Martin
authors.forename: Shanon
authors.initials: S
authors.lastname: Bachman
authors.forename: James
authors.initials: J
authors.lastname: Mitchell
authors.forename: Rachael
authors.initials: R
authors.lastname: Aubert
authors.forename: Theodros
authors.initials: T
authors.lastname: Solomon Tsegaye
authors.forename: Ellen
authors.initials: E
authors.lastname: Kersh
authors.forename: Chou-Pong
authors.initials: CP
authors.lastname: Pau
authors.forename: Walid
authors.initials: W
authors.lastname: Heneine
authors.forename: J Gerardo
authors.initials: JG
authors.lastname: García-Lerma
mesh_terms: D000818:Animals; D044966:Anti-Retroviral Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D018890:Chemoprevention / Q000379:methods*; D003510:Cyclohexanes / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D005260:Female; D007413:Intestinal Mucosa / Q000737:chemistry; D008251:Macaca; D008297:Male; D000077592:Maraviroc; D010949:Plasma / Q000737:chemistry; D012007:Rectum / Q000737:chemistry*; D016097:Simian Acquired Immunodeficiency Syndrome / Q000517:prevention & control*; D017211:Treatment Failure; D014230:Triazoles / Q000008:administration & dosage* / Q000493:pharmacokinetics*
chemical_list: D044966:Anti-Retroviral Agents; D003510:Cyclohexanes; D014230:Triazoles; D000077592:Maraviroc