Pfizer Inc announced today that the European Commission has approved the antiretroviral drug maraviroc for treatment-experienced patients in the European Union (EU). Maraviroc, which was approved in the United States under the name Selzentry in August, will be sold as Celsentri in Europe. Maraviroc belongs to a new class of drugs, called CCR5 antagonists, which are effective only in people with CCR5-tropic HIV—virus that uses the CCR5 coreceptor to infect CD4 cells.
EU approval of maraviroc was based on encouraging 48-week efficacy and safety data from two Phase III clinical trials involving heavily treatment-experienced patients. Compared with participants on placebo plus an optimized background regimen, participants who took maraviroc combined with an optimized background regimen were more than twice as likely to have an undetectable viral load after 48 weeks of treatment.
Maraviroc was not approved in the EU for people starting HIV treatment for the first time. People wishing to use maraviroc as part of an HIV treatment regimen must first take a blood test to determine which coreceptor their virus uses to infect T-cells, known as virus tropism. If a person’s virus uses only the CCR5 coreceptor, maraviroc is likely to be effective. If the virus uses CXCR4, or both CCR5 and CXCR4, marviroc will not be effective.
