Pfizer to Launch Antiretroviral Maraviroc in July After FDA Tests Conclude, Official Says

Pharmaceutical company Pfizer will launch its antiretroviral drug maraviroc in July after FDA tests conclude in the U.S., Richard Paulson, head of Pfizer in South Africa, said on Wednesday, AFP/Japan Today reports. According to an unnamed Pfizer spokesperson, the drug, which will be taken orally, is scheduled to be formally approved by FDA on June 20 (AFP/Japan Today, 6/7). An FDA panel of outside experts in April unanimously recommended that the agency approve maraviroc.

Pfizer has proposed using the drug to treat people with advanced HIV or AIDS who have not responded to other medications. Maraviroc works by blocking a protein, called CCR5, on human immune system cells that HIV uses as a portal to enter and infect the cell. Pfizer plans to offer the drug with a test developed by Monogram Biosciences that determines if people likely will respond to the treatment.

FDA in April raised concerns that maraviroc could be associated with an increased risk of liver damage, lymphoma and infections. According to FDA, other CCR5 inhibitors under development have been shown to increase safety risk issues. Pfizer said its studies have shown that maraviroc has no significant effect on the heart and did not increase the incidence of liver problems, cancer or infection compared with other HIV/AIDS drugs.

Although FDA in April said it "continues to be concerned about potential safety issues with the entire class of drugs," some agency reviewers said they noted no increases in lymphomas or infections among people taking maraviroc. FDA reviewers have noted a "modest" increase in liver problems among people taking the drug. Pfizer has proposed selling maraviroc under the brand name Celsentri (Kaiser Daily HIV/AIDS Report, 4/25).

In related news, Pfizer on Wednesday announced that it has applied for fast-track approval of maraviroc from South Africa's Medicines Control Council, Business Day/AllAfrica.com reports (Rego, Business Day/AllAfrica.com, 6/7).

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