Tifuvirtide (also known as T 1249) is a synthetically designed hybrid retroviral envelope polypeptide patented by Trimeris, Inc. as fusion inhibitor useful for the treatment of HIV infection. Tifuvirtide binds to HIV glycoprotein 41 (gp41) and prevents its fusogenic conformation, inhibiting viral entry into host cells. Tifuvirtide is composed of sequences from HIV-1, HIV-2, and simian immunodeficiency virus. Tifuvirtide has greater potency in vitro, compared with enfuvirtide, and elicits activity against most enfuvirtide-resistant isolates in vitro and in vivo. A successful short-term phase 1/2 studies evaluation of antiretroviral activity and safety in humans proved the potential of this new drug, although further clinical development was discontinued.

Enfuvirtide is a linear 36-amino acid synthetic peptide that inhibits the fusion of HIV-1 with CD4 cells. Enfuvirtide works by disrupting the HIV-1 molecular machinery at the final stage of fusion with the target cell, preventing uninfected cells from becoming infected. Enfuvirtide interferes with the entry of HIV-1 into cells by inhibiting fusion of viral and cellular membranes. Enfuvirtide binds to the first heptad-repeat (HR1) in the gp41 subunit of the viral envelope glycoprotein and prevents the conformational changes required for the fusion of viral and cellular membranes. Enfuvirtide is indicated for the treatment of HIV-1 infection, in combination therapy with other antiretrovirals, in patients where all other treatments have failed. Common adverse drug reactions associated with enfuvirtide therapy include: injection site reactions (pain, hardening of skin, erythema, nodules, cysts, itch; experienced by nearly all patients, particularly in the first week), peripheral neuropathy, insomnia, depression, cough, dyspnoea, anorexia, arthralgia, infections (including bacterial pneumonia) and/or eosinophilia.

Bictegravir is a component of the fixed-dose combination product bictegravir/emtricitabine/tenofovir alafenamide (BIKTARVY®), which received marketing approval for the treatment of human immunodeficiency virus (HIV) infection by the U.S. Food and Drug Administration in February 2018. Bictegravir inhibits the strand transfer activity of HIV-1 integrase, an HIV-1 encoded enzyme that is required for viral replication. Inhibition of integrase prevents the integration of linear HIV-1 DNA into host genomic DNA, blocking the formation of the HIV-1 provirus and propagation of the virus.

Peramivir is a transition-state analogue and a potent, specific influenza viral neuraminidase inhibitor. Rapivab (peramivir injection) is indicated for the treatment of acute uncomplicated influenza in patients 18 years and older who have been symptomatic for no more than 2 days. Efficacy of Rapivab is based on clinical trials in which the predominant influenza virus type was influenza A and a limited number of subjects infected with influenza B virus were enrolled. Since influenza viruses change over time emergence of resistance substitutions could decrease drug effectiveness. Other factors such as changes in viral virulence might also diminish clinical benefit of antiviral drug. Efficacy could not be established in patients with serious influenza requiring hospitalization.