Future of maraviroc and other CCR5 antagonists

Current antitretroviral therapy, although very effective in reducing the mortality and morbidity of HIV infection, remains challenged by the emergence of antiviral resistance. The development of a new class of antiretroviral drugs, based on the unique use of the chemokine receptor, CCR5, for initial viral entry into cells, offers an opportunity to overcome current resistance. Chemokine receptor antagonists, of which maraviroc is the leading product in development, are active in vitro and in vivo against both wild-type HIV and strains resistant to current drugs. Current Phase III trials help determine their place in HIV therapeutics, as well as the relative importance of viruses that utilize an alternative receptor, CXCR4.