TUESDAY, April 24, 2007 (HealthDay News) -- A U.S. Food and Drug Administration advisory panel on Tuesday unanimously recommended the approval of the first of a new class of HIV-suppressing medications.
The drug, Pfizer Inc.'s maraviroc, is in a class of agents called CCR5 antagonists. The FDA panel is recommending approval of the drug for patients already taking other anti-HIV medications. Pfizer would sell the drug under the brand name Celsentri.
According to the 12-member panel, the drug's benefits outweigh its risks, Bloomberg News reported. Although the FDA does not have to follow its advisory panels' recommendations, it usually does.
"The drug is needed by a certain portion of the population, and I think the benefits and risks clearly support its approval as soon as possible,'' Peter Havens, a panel member and a professor of pediatrics at the Medical College of Wisconsin, told Bloomberg.
"This is a new class of drug," added Dr. Jeffrey Laurence, director of the Laboratory for AIDS Virus Research at Weill Medical College of Cornell University, in New York City. "It attacks part of the way HIV binds to a cell," he explained. "It looks spectacular in phase II and phase III testing, in terms of lowering virus loads and increasing CD4 T-cell counts."
Viral load is the amount of the virus present in the blood, and CD4 T-cells are both an important component of the body's immune system and prime targets for HIV.
The drug is designed to be used with other HIV-suppressing drugs, especially in people who have strains of the virus that are resistant to other medications, Laurence said.
Maraviroc works by preventing the AIDS virus from entering cells. It does so by blocking a cell surface co-receptor called CCR5, which usually allows the virus to pass into cells.
"The drug prevents the virus from binding with the CCR5 molecule," Laurence explained.
In recent a trial of more than 1,000 people, maraviroc suppressed the virus in 45 percent of patients, compared with 23 percent of those who were taking a placebo. People in the trial were also taking other HIV drugs.
There had been concerns that maraviroc could cause serious complications, such as heart damage, cancer and liver damage. However, the results of the trial have so far found no substantial harmful side effects, Laurence said.
"Development of new classes of HIV drugs is critically important," Laurence said. "We are getting more and more spread of resistant virus as people get tired of the drugs they are on or tired of the side effects of the drugs they are on. In addition, adherence to drug regimens is a problem. Because of that, we are always looking for new agents."
Laurence noted that many people with HIV now view it as a chronic disease. "But it can only be a chronic disease if we can keep up with resistant strains of the disease," he said. "Maraviroc is another tool we can use."
More information
For more information on HIV/AIDS, visit the U.S. National Institute of Allergy and Infectious Diseases.
