Pharmaceutical Companies Working To Develop CCR5 Inhibitor Drugs To Treat HIV Infection

　　Several pharmaceutical companies are "racing" to bring to market a new class of antiretroviral drugs, called CCR5 inhibitors, that would prevent HIV from entering human cells rather than fighting the virus once it has entered cells, Reuters reports (Hirschler, Reuters, 2/16). CCR5 inhibitors block HIV from docking with a human cell's CCR5 receptor, which is where HIV latches onto a cell to enter it. Previous studies have shown that people who lack CCR5 receptors because of genetic mutations rarely contract HIV. Drug companies Pfizer, GlaxoSmithKline and Schering-Plough currently are conducting clinical trials testing CCR5 inhibitors. The compounds developed by GSK in partnership with Schering-Plough have had no harmful side effects in early studies, and the companies hope to file for FDA approval as early as 2007. The Pfizer compound has entered Phase III trials (Kaiser Daily HIV/AIDS Report, 1/6). Dr. Graeme Moyle, an HIV expert at the Chelsea and Westminster Hospital in London, said, "We need these drugs," adding, "We have downsides with the medications we have at present in terms of toxicity, in terms of patient adherence and in terms of the management of virus resistance, which makes the need for new drug classes absolutely critical." The experimental drugs are expected to be discussed at the 12th Conference on Retroviruses and Opportunistic Infections next week in Boston, according to Reuters.