European Commission Approves Pfizer's CCR5 Inhibitor Maraviroc

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Pfizer's Antiretroviral Drug

Pfizer on Monday announced that the European Commission has approved its antiretroviral drug Celsentri, known generically as maraviroc, for sale and marketing in the European Union, Dow Jones/CNNMoney.comreports (Berton, Dow Jones/, 9/24). Maraviroc belongs to anew class of antiretrovirals that could provide an alternative toHIV-positive people who have developed resistance to multiple drugs.The treatment works by blocking a protein, called CCR5, on human immunesystem cells that HIV uses as a portal to enter and infect the cell.


Pfizer has proposed using the drug to treat people with advanced HIV or AIDS who have not responded to other medications. FDAin August approved maraviroc on the condition that the drug's labelinclude a black box warning about an increased risk of heart attack.FDA also is requiring Pfizer to conduct further research into thedrug's long-term side effects (Kaiser Daily HIV/AIDS Report, 9/20). Maraviroc is sold under the brand-name Selzentry in the U.S. (Dow Jones/, 9/24).

According to a Pfizer release,the European Commission approved maraviroc based on 48-week data fromtwo ongoing clinical trials (Pfizer release, 9/24). The data showedthat nearly three times as many HIV-positive people who took maravirocin combination with a traditional treatment regimen achievedundetectable levels of HIV, compared with those receiving only thetraditional regimen. Pfizer also said that CD4+ T cell countssignificantly were increased among people taking maraviroc, comparedwith participants who took only the standard regimen. Pfizer last weeksaid the side effects recorded among participants who took maravirocresembled those experienced by participants who received only thetraditional regimen. The most common side effects reported includeddiarrhea, nausea, fatigue and headache (Kaiser Daily HIV/AIDS Report, 9/20).

"Theapproval of maraviroc will offer a new option to many people livingwith HIV in Europe," Filippo von Schloesser -- president of Fondazione Nadir Onlus,an Italian organization for people living with HIV/AIDS -- said, addingthat "resistance to current treatments is one of the biggest challengesfacing HIV care today" (Pfizer release, 9/24).

Reprinted with permission from You can view theentire Kaiser DailyHIV/AIDS Report, search the archives, and sign up for email delivery at . TheKaiser Daily HIV/AIDS Report is published for, a free service ofThe Henry J. Kaiser Family Foundation.