Maraviroc: the evidence for its potential in the management of HIV

INTRODUCTION: New antiretroviral agents that are more convenient, better tolerated with fewer short- and long-term side effects, and that have novel resistance patterns are needed at all lines of therapy in patients infected with human immunodeficiency virus (HIV). Therefore, next generation products of current classes and alternative classes of antiretroviral agents are needed. The CC-chemokine receptor 5 (CCR5) antagonists are a novel class of antiretroviral agents that prevent the entry of HIV into host cells by blocking the CCR5 coreceptor. Within this class, maraviroc is the agent furthest along in development. AIMS: The aim of this review is to evaluate the emerging evidence for the use of the CCR5 antagonist maraviroc in antiretroviral treatment-naïve and treatment-experienced patients with HIV-1 infection. EVIDENCE REVIEW: Preliminary evidence from phase I/IIa short-term studies suggest that maraviroc monotherapy is effective at reducing HIV viral load, and is generally well tolerated. In-vitro evidence suggests that maraviroc will be effective in drug-naïve patients with CCR5-tropic virus, as well as in those with CCR5-tropic virus who have developed HIV resistance to existing antiretroviral regimens. However, it is not known how quickly resistance may develop to maraviroc in clinical practice. CLINICAL POTENTIAL: Current evidence supports the continued development of maraviroc as a potentially useful, alternative treatment for the management of HIV infection. Maraviroc monotherapy has a high potency and long half-life, allowing single-pill dosing. Therefore, it is expected that maraviroc will have a beneficial effect on patient adherence and viral load in combination with other antiretroviral agents. Maraviroc is only effective against CCR5-tropic virus, which predominates throughout infection but is more common in patients at the early asymptomatic stage of infection.