US okays Pfizer’s new anti-HIV drug Maraviroc

15 August, 2007:

Pfizer Incorporated, the world’s biggest manufacturer of medicines, has won the United States’ approval for Maraviroc, the first new type of medicine in a decade to treat the virus that causes AIDS.

The oral pill was cleared by the US Food and Drug Administration (FDA) for patients who have failed to reduce the levels of the human immunodeficiency virus (HIV) with other treatments, Pfizer has said in a statement.

Maraviroc, to be sold under the name Selzentry, will provide an alternative for thousands of Americans with drug-resistant forms of HIV, claims the New York-based Pfizer.

The drug will cost about $900 a month wholesale, comparable to other HIV treatments. Pfizer said it expects Maraviroc to be available in the United States by the middle of September 2007.

An advisory panel of the US Food and Drug Administration had recommended in April 2007 that the FDA make the drug available quickly to the 25,000 to 40,000 people who may benefit because their infections resist other treatments. Pfizer also needs to conduct additional studies on Maraviroc’s side effects and which population groups ought to use it, the advisory panel had then said.

Steven Galson, director of the FDA’s Center for Drug Evaluation and Research, said in a statement that “this is an important new product for many HIV-infected patients who have not responded to other treatments and have few options.”

The FDA found no unusual deaths linked to Maraviroc. People who took the drug were more likely to develop flu-like illnesses or herpes. The product’s prescribing information includes a boxed warning about liver damage and a statement about the possibility of heart attacks, an FDA statement said.

Pfizer had said on June 20, 2007 that the FDA had delayed approval of the drug because of undisclosed issues with its labeling.

Maraviroc is the first in a new class that blocks the CCR5 receptor, a chemical portal used by HIV to get into healthy cells. The drug changes the shape of the entryway, making it impossible for HIV to get in.

The medicine will be given to patients as an oral pill to be taken twice a day. It must be given in combination with other HIV medications.

About half of the 1 million people in the United States with HIV are infected with a form of the virus that uses the CCR5 entryway. Patients will have to get a test, available from Monogram Biosciences Incorporated of South San Francisco, California, to determine whether their type of HIV could be targeted by the drug. The test, called Trofile, is 90% accurate.

Monogram retains commercial rights to Trofile in the United States, and Pfizer will sell it outside the US, according to an official of Monogram.

Another HIV medicine, Isentress from Merck & Company, could be approved by the FDA in October 2007.

Two other drugs in the same class as Maraviroc were rejected because of their side effects. GlaxoSmithKline Plc stopped trials of its Aplaviroc because of liver damage among patients, and Schering-Plough Corporation’s Vicriviroc was linked to lymphoma.