Maroviroc (Selzentry) from Pfizer safe for first-time HIV treament: US FDA panel

Maraviroc is currently approved as secondary treatment for HIV patients

Maraviroc sold under the brand name Selzentry by Pfizer could be approved to treat HIV patients who have not already taken other drugs.

US Food and Drug Administration’s Antiviral Drugs Advisory Committee voted (10 to 4) to recommend the approval of Selzentry (maraviroc) tablets for use in treatment-naïve adult patients with CCR5-tropic HIV-1 virus as part of combination therapy, Pfizer said in a news release.

The FDA often seeks the advice of its Advisory Committees when evaluating potential treatments.

Selzentry is approved as a secondary treatment for HIV patients who are not responding to other antiviral drugs.

“Pfizer is pleased that the Committee has recognized the effectiveness and safety profile of maraviroc in patients who are starting HIV therapy,” said Dr. Howard Mayer, Pfizer’s executive director and disease area leader, antivirals.

Selzentry (maraviroc) is an oral medicine that blocks viral entry to human cells. Rather than fighting HIV inside white blood cells, Selzentry prevents the virus from entering uninfected cells by blocking its predominant entry route, the CCR5 co-receptor.

Selzentry (maraviroc) was granted accelerated approval in August 2007 and full approval in November 2008 by the FDA for use in treatment-experienced adult patients with only CCR5-tropic HIV-1 virus in combination with other antiretroviral therapies.

Selzentry has also been approved in several other markets around the world including the U.S., Canada and the European Union.

Maraviroc is marketed under the trade name Selzentry in the US and Celsentri in all other countries in which it is approved.

US FDA Advisory Committee reviewed 48- and 96-week efficacy and safety data from the ongoing Phase 3 MERIT (Maraviroc versus Efavirenz Regimens as Initial Therapy) trial and MERIT ES (analysis of the MERIT study with the enhanced sensitivity Trofile assay).

Selzentry plus Combivir (zidovudine/lamivudine) was as effective as BMS’ Sustiva (efavirenz) plus zidovudine/lamivudine at reducing viral load for the co-primary endpoint of <400 copies/mL, but did not show non-inferiority for the co-primary endpoint of <50 copies/mL at 48-weeks, showed results of MERIT at 48-weeks study.

Results of MERIT ES at 48-weeks showed that treatment-naïve patients with CCR5-tropic HIV-1 taking Selzentry plus zidovudine/lamivudine experienced comparable virologic suppression to undetectable levels to those taking efavirenz plus zidovudine/lamivudine.

Safety results at 96-weeks showed that among those patients who remained on therapy, less than half the number of malignancies were observed in patients taking Selzentry compared to those taking efavirenz.

Selzentry had sales of $46 million last year, according to Pfizer.

Selzentry would be the most expensive first-line HIV treatment on the U.S. market, according to the AIDS Healthcare Foundation, a nonprofit patient advocacy group. Selzentry’s wholesale price per year is over $12,500, according to the group, compared with $4,800 for Bristol-Myers’ Sustiva.

Pfizer plans to expand the reach of maraviroc through the joint venture with GlaxoSmithKline, which is expected to close in the fourth quarter of 2009.

An estimated 1.1 million people in the U.S. were living with HIV infection. The Centers for Disease Control and Prevention (CDC) estimates that in 2006 approximately 56,300 people were newly infected with HIV in the U.S.

Pfizer is the world’s leading biopharmaceutical company.