Pfizer, Inc., recently announced that the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMEA) issued a positive opinion recommending marketing authorization for Celsentri® (maraviroc), the first CCR5 antagonist for use in combination with other antiretroviral agents for treatment-experienced adult patients where only CCR5-tropic virus is detectable. The CHMP’s positive opinion will be reviewed by the European Commission, which has authority to approve medicines for the European Union. Pfizer anticipates a final decision from the Commission in the coming months. “New, effective and well-tolerated treatments are urgently needed for the thousands of people living with HIV whose virus has become resistant to one or more currently available options. Recognizing the needs of these patients, Pfizer moved with urgency in the research and development for maraviroc,” said Dr. Joseph Feczko, Pfizer’s Chief Medical Officer. Subject to the necessary regulatory approvals, Pfizer will make this novel medicine available to patients as Celsentri outside the US. Pfizer has recently received an approvable letter for maraviroc from the US Food and Drug Administration (FDA). Maraviroc is the first member of a new class of oral HIV medicines in more than a decade (CCR5-antagonists). Discovered and developed by Pfizer scientists in Sandwich, England, since 1997, maraviroc works extracellularly by blocking viral entry to human cells. Rather than fighting HIV inside white blood cells, maraviroc prevents the virus from entering white blood cells by blocking its predominant entry route, the CCR5 co-receptor. In the treatment of HIV two parameters are considered main markers of treatment success: viral load reduction and increase of CD4 white cells. The maraviroc MOTIVATE pivotal trials compared the safety and efficacy of the addition of maraviroc to an optimized combination drug regimen (referred to as optimized background therapy-OBT) to the addition of placebo to OBT.