Fuzeon (enfuvirtide for injection)

Enfuvirtide is the first drug to be approved in a new class of anti-HIV drugs known as fusion inhibitors (see "Focus On... Enfuvirtide"). The drug interferes with the entry of HIV-1 into immune cells by inhibiting the fusion of viral and cellular membranes. This occurs when enfuvirtide prevents conformational changes required for the fusion of viral and cellular membranes by binding to the first heptad-repeat (HR1) in the gp41 subunit of the viral envelope glycoprotein. Enfuvirtide, in combination with other antiretroviral agents, is intended for the treatment of HIV-1 infection in treatment-experienced patients with evidence of HIV-1 replication despite ongoing antiretroviral therapy.