Pfizer's maraviroc impresses in HIV trials

USA-based drug giant Pfizer says that 24-week data from a trial of its antiviral maraviroc indicate that nearly double the number of HIV infected patients receiving the drug in combination with optimized background treatment achieved undetectable viral loads, compared with those treated with background therapy alone. The findings were presented at the Conference on Retroviruses and Opportunistic Infections in Los Angeles, USA.

The agent, which was discovered in 1997, is an oral medication that prevents viral entry into human white blood cells by blocking the CCR5 protein co-receptor. This novel mechanism of action differs from most currently-available therapies, which focus on preventing replication once the virus has entered the cell.

The firm said that the results, which are derived from the ongoing MOTIVATE Phase IIb and Phase III studies, are remarkably consistent in terms of the drug's impact on viral load. In addition, the data demonstrate that around twice as many patients who received the product as part of once or twice-daily treatment regimen achieved an increase in CD4 T-lymphocyte levels, compared with those in the control group (107 cells/mm3 and 111 cells/mm3 versus 52 cells/mm3 in MOTIVATE-1 and 112 cells/mm3 and 102 cells/mm3, vs 64 cells/mm3 in MOTIVATE-2, respectively).