Vicriviroc or SCH 417690 is a potent and selective antagonist of the CCR5 receptor. vicriviroc binds specifically to the CCR5 receptor and prevents infection of target cells by CCR5-tropic HIV-1 isolates. In antiviral assays, vicriviroc showed potent, broad-spectrum activity against genetically diverse and drug-resistant HIV-1 isolates and was consistently more active than SCH-C in inhibiting viral replication. This compound demonstrated synergistic anti-HIV activity in combination with drugs from all other classes of approved antiretrovirals. Competition binding assays revealed that vicriviroc binds with higher affinity to CCR5 than SCH-C. Functional assays, including inhibition of calcium flux, guanosine 5'-[35S]triphosphate exchange, and chemotaxis, confirmed that vicriviroc acts as a receptor antagonist by inhibiting signaling of CCR5 by chemokines. Finally, vicriviroc demonstrated diminished affinity for the human ether a-go-go related gene transcript ion channel compared to SCH-C, suggesting a reduced potential for cardiac effects. Vicriviroc represented a promising new candidate for the treatment of HIV-1 infection. Vicriviroc for HIV treatment was previously in Phase III studies but has since been discontinued.

Enviradene (LY 127123) is a benzimidazole antiviral compound. It inhibited picornavirus replication and infection in vitro.

Denotivir is an organic chemical compound with antiviral activity. In vitro antiviral activity of denotivir has been demonstrated against human HSV types 1 and 2, and varicella zoster virus (VZV). Clinical trials with vratizolin have given impressive results in the patients with local HSV infections and very good results in VZV infections. Genital herpes, a sexually transmitted HSV infection, whose incidence is increasing and whose treatment has never been adequate, appears to respond well to the treatment with vratizolin with very good results. Very good therapeutic results were also obtained by applying vratizolin to the patients with an ophthalmic HSV infection. Vratizolin exerted strong immunosuppressive actions. Vratizolin inhibited to some degree LPS-induced cytokine production in human peripheral blood cultures. The activities of TNF-alpha, IL-1 and IL-6 were inhibited on average by 37, 26 and 35%, respectively.

Torcitabine is the beta-L-enantiomer of the natural nucleoside D-cytidine. The drug was under development as an antiviral agent for the treatment of chronic hepatitis B virus infection. Torcitabine has poor oral bioavailability, but its 3’,5’-derivative ester (val-L-dC) and the 3’-monovaline ester, valtorcitabine dihydrochloride, have excellent oral bioavailability and consequently the torcitabine prodrug, valtorcitabine, has replaced torcitabine in clinical development. Torcitabine is active against hepadnaviruses, specifically human hepatitis B virus (HBV), duck hepatitis virus (DHBV) and woodchuck hepatitis virus (WHV). Torcitabine triphosphate is a selective inhibitor of the polymerase enzyme of HBV.

Mimbane was developed by Parke-Davis as an analgesic. Information about the current use of the drug is not available.

Lodenosine is the experimental HIV reverse transcriptase inhibitor. It was designed as a chemically and enzymatically stable anti-AIDS drug. A phase II trial of the nucleoside analog lodenosine was suspended after one participant died and others showed signs of liver or kidney damage.

Tivirapine, also known as R-86183, is a HIV-1 specific reverse transcriptase inhibitor. It inhibits the replication of HIV-1, but not HIV-2, in a variety of CD4+ T-cell lines and peripheral blood lymphocytes. Whereas an HIV-1 strain containing the Leu-100-->Ile mutation in the RT gene is about 400-fold less susceptible, R86183 still inhibits the replication of an HIV-1 strain containing the Tyr-181-->Cys RT mutation by 50% at a concentration of 130 nM. Tivirapine had been in phase I clinical trial for the treatment of HIV-1 infection. However, this development was discontinued.

Ancriviroc (SCH 351125) is a small-molecule antagonist of the human immunodeficiency virus type 1(HIV-1) coreceptor CCR5. It has in vitro activity against R5 viruses with 50% inhibitory concentrations ranging from 1.0 to 30.9 nM. Ancriviroc is an orally bioavailable small molecule inhibitor of HIV-1 entry via CCR5 coreceptor interaction. Ancriviroc has potent activity against RANTES binding (K(i) = 2 nM), possesses subnanomolar activity in blocking viral entry and has excellent antiviral potency versus a panel of primary HIV-1 viral isolates. Ancriviroc had been in phase I clinical trials by Schering-Plough (subsidiary of Merck Sharp & Dohme) for the treatment of HIV infection. However, this research has been discontinued.

MKC-442 (6-benzyl-1-(ethoxymethyl)-5-isopropyl-uracil) is a highly potent and selective inhibitor of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT). Emivirine structurally is a nucleoside analog (NRTI) molecule, but it functions as a non-nucleoside reverse transcriptase inhibitor (NNRTI). Emivirine had reached phase 3 clinical trials for the treatment of HIV-1 infections before its further development was stopped.

Navuridine (AzddU) is a nucleoside analogue which demonstrated significant anti-HIV activity and low toxicity in preclinical studies. The drug was originally developed by University of Georgia. Navuridine is a dideoxyuridine inhibitor of HIV reverse transcriptase that is related to zidovudine. Navuridine exhibits a relatively short half-life and incomplete oral bioavailability and has not been developed into a clinical drug.