Maraviroc Shows Significant Benefits in HIV Positive Patients
By Pfizer
Jul 31, 2005, 21:23

Results from early-stage clinical trials, presented today at the 3rd International AIDS Society Conference on Pathogenesis and Treatment, indicate that maraviroc, an investigational drug for treatment of HIV/AIDS, was well-tolerated and decreased patient levels of HIV significantly in 10-day monotherapy studies in asymptomatic HIV-positive patients.

Maraviroc works through a different mechanism of action from currently marketed drugs. In a category of compounds known as "CCR5-antagonists," maraviroc blocks HIV from entering white blood cells, where the virus replicates, takes over the cell's DNA for its own reproduction, and ultimately destroys a patient's immune system.

Safety data from six multi-dose phase 1/2a studies involving 259 healthy and HIV-positive volunteers showed that maraviroc's safety and toleration profile was similar to placebo in doses up to 300 mg twice-daily in short term studies, with headache, dizziness, nausea, asthenia, and flatulence as the most common adverse events reported. In two 10-day monotherapy studies in 63 patients, maraviroc reduced HIV viral load by 1.6-1.84 log (logarithmic measures of virus per milliliter of blood) at all total daily doses tested from 200 to 600 mg. The data also showed that maraviroc's efficacy did not change following dosing with or without food. All doses tested for efficacy from 200 mg total daily dose to 600 mg total daily dose caused a similar reduction in patient's viral load.

Pfizer researchers at the company's Sandwich, UK laboratories identified the lead compound that they ultimately refined to become maraviroc in 1997. Maraviroc is now in advanced development, currently enrolling worldwide phase 2b/3 trials. An independent Data Safety Monitoring Board (DSMB) comprised of international experts oversees these studies.

Independent of the data presented at the IAS conference, Pfizer also announced that the U.S. Food and Drug Administration has granted fast track designation for maraviroc's clinical development program. FDA based the fast-track designation on the potential for maraviroc's mechanism of action to meet an unmet medical need in HIV patients who have exhausted currently available options, the company said.

"We are pleased that FDA recognizes the value of maraviroc's innovative mechanism and the possibilities that a novel therapy brings to this high-medical need for a growing population," said John LaMattina, Ph.D., president of Pfizer Global Research and Development. "The data presented today support our continuing worldwide study of maraviroc."

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