Trovirdine [LY 300046, LY 300082, PETT 1] is a NNRT inhibitor of HIV-1 RT, which progressed through Phase II trials for the treatment of HIV infection. Trovirdine inhibits HIV-1 RT with an IC50 of 7 nM. Cell culture experiments demonstrated that LY300046 was a potent inhibitor of the replication of HIV-1 in human T-cell lines and human PBL, including spread of the virus from infected to uninfected T cells. It was potent against patient isolates as well as laboratory isolates of HIV-1 but was not active against HIV-2 or simian immunodeficiency virus.

Fosarilate was studied as an antiviral agent. Information about the current use of this compound is not available.

Somantadine, an adamantane derivative, is an antiviral agent. Somantadine was synthesized by Pennwalt and has been undergoing tests for the treatment of herpes virus for nearly five years.

Brecanavir (previously known as VX-385), a HIV aspartyl protease inhibitor was developed for the treatment of HIV. The inhibition of HIV viral proteinase enzyme prevents cleavage of the gag-pol polyprotein, resulting in noninfectious, immature viral particles. Brecanavir reached Phase II development. However, GlaxoSmithKline announced to discontinue development brecanavir. Because of the inability to develop a viable oral dosage formulation capable of delivering the desired brecanavir levels in patients with multi-drug resistant HIV.

Memotine (UK2371)is an isoquinoline antiviral compound. In vitro, it is active against myxoviruses and paramyxoviruses. It is not active against rhinoviruses. Memotine given orally reduces the antibody response and the incidence of clinical reactions.

Talviraline (HBY 097) was developed as a nonnucleoside inhibitor of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (NNRTI) for the treatment of HIV Infections. Talviraline participated in a phase II clinical trial. It was found that the drug caused pronounced acute suppression of HIV-1 replication both in combination with zidovudine and alone. However, further development of the drug has been discontinued.

Mozenavir is a non-peptidomimetic, water soluble, cyclic urea that is a selective inhibitor of HIV-1 protease. Mozenavir is active against the virus with the signature D30N nelfinavir resistance-associated mutation and the L90M mutants with decreased susceptibility to a number of other protease inhibitors. In a dose-ranging study assessing Mozenavir, in doses of 750 mg 3 times a day, 1250 mg twice daily, or 1250 mg 3 times a day, compared with standard doses of indinavir, both in combination with lamivudine and stavudine, plasma HIV-1 RNA levels were reduced to below 50 copies/mL in 75% to 80% of patients receiving Mozenavir-based treatment and in 70% of those receiving indinavir-based treatment. Mozenavir-based regimens were generally well tolerated. However, the virus was able to mount considerable resistance against this compound, which was not further developed, also because of poor oral bioavailability in humans and highly variable blood levels.

Citenazone (Hoe 105) is an antiviral compound, developed in the 1970s by Hoechst. It is claimed to have activity for vaccinia infection in mice, baby rats, and rabbits, and for variola infection in baby mice.

Ciluprevir (BILN-2061) is a selective inhibitor of the HCV NS3 serine protease, which was developed by Boehringer Ingelheim for the treatment of hepatitis C infection. The drug was discontinued in phase II due to adverse events such as cardiac toxicity (demonstrated in animals). In the cell-based replicon assay, ciluprevir inhibited HCV RNA replication at low nanomolar levels. It had inhibitory rate constant (Ki) values of 0.3 and 0.66 nM for the NS3 proteases of HCV genotypes 1a and -1b, respectively.

Taribavirin, an oral prodrug of ribavirin that was developed as nucleoside antimetabolite, which interferes with duplication of viral genetic material. Taribavirin was studied in phase III clinical trial for the treatment of chronic hepatitis C patients. However, this drug not yet approved for pharmaceutical use.