Key Hearing Awaits Pfizer Drug

A panel of outside medical experts is meeting Tuesday to evaluate a Pfizer(PFE) HIV and AIDS drug that, if approved, would the the first in a new class of treatments.

Pfizer is seeking support from the Food and Drug Administration for maraviroc, a pill being targeted at patients for whom other drugs, or drug combinations, have become ineffective.

Maraviroc "could broaden the arsenal of treatments to combat resistant forms" of the virus that causes AIDS, Pfizer told analysts last week when it issued first-quarter results. Maraviroc would be the first new oral class of HIV, or human immunodeficiency virus, medicines in more than 10 years, Pfizer said.

The FDA advisory panel must decide if Pfizer has proven that its drug can avoid the setbacks found in other compounds in this class, known as CCR5 antagonists.

GlaxoSmithKline(GSK) halted work in October 2005 after its drug caused liver damage. The compound was in the third and final stage of clinical trials.

In August 2006, Schering-Plough(SGP) said it was initiating a new phase II trial of its product because five patients in an earlier study developed different types of cancer. The company said it couldn't tell from the earlier trial if there was a link between its drug and the cancers.

So far, it appears that Pfizer's drug hasn't experienced the types of side effects that affected other CCR5 drugs, said an FDA staff report issued Friday. The FDA noted a "modest increase" in liver-related side effects. The data are being analyzed to determine if side effects were caused by Pfizer's drug, alcohol, another AIDS drug or viral hepatitis.