Pfizer says that its marketing authorisations for the HIV treatment maraviroc will receive an accelerated review from regulators both in the USA and Europe.

If approved by the regulatory agencies, the company said that maraviroc will be the first in a new class of HIV/AIDS treatments called CCR5 antagonists that work by blocking viral entry. Rather than fighting HIV inside white blood cells, they prevent the virus produced by infected cells from entering uninfected cells by blocking its predominant entry route, the CCR5 co-receptor.

The US Food and Drug Administration’s priority review process takes place within a six-month period and as Pfizer submitted both marketing applications in December 2006, it expects to hear from an agency advisory panel on or before April 24. Regulatory approval for maraviroc is being sought in other countries.

John LaMattina, president of Pfizer R&D said that “there is a profound global need for new medicines to help HIV/AIDS patients," and CCR5 antagonists “will become critically important new treatment options for patients who are resistant or intolerant” to their current therapies."

The marketing applications for maraviroc were based on Pfizer's review of efficacy and safety data from two pivotal Phase III trials. MOTIVATE-1 and 2, which represent 24-week data that compares optimised background therapy, with or without the drug, in over 1,000 highly treatment-experienced patients with CCR5-tropic HIV-1. The company also noted that its previously announced multi-national expanded access programme to provide maraviroc to patients with limited available treatment options is now open for enrollment.

If maraviroc does get approval, future competition could come from Schering-Plough’s vicriviroc which is currently in Phase II.

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