NBD-557 is a potentially HIV-1 inhibitor.IC50 Value: Target: HIVNBD-557, is small molecule organic compounds with drug-like properties. It showed potent cell fusion and virus-cell fusion inhibitory activity at low micromolar levels. A systematic study showed that NBD-557 target viral entry by inhibiting the binding of HIV-1 envelope glycoprotein gp120 to the cellular receptor CD4 but did not inhibit reverse transcriptase, integrase, or protease, indicating that they do not target the later stages of the HIV-1 life cycle to inhibit HIV-1 infection. NBD-557 potent inhibitors of both X4 and R5 viruses tested in CXCR4 and CCR5 expressing cell lines, respectively, indicating that its anti-HIV-1 activity is not dependent on the coreceptor tropism of the virus. A surface plasmon resonance study, which measures binding affinity, clearly demonstrated that NBD-557 bind to unliganded HIV-1 gp120 but not to the cellular receptor CD4. NBD-557 was active against HIV-1 laboratory-adapted strains including an AZT-resistant strain and HIV-1 primary isolates, indicating that NBD-557 can potentially be further modified to become potent HIV-1 entry inhibitors.

[1]. Sch•n A, Madani N, Klein JC, Hubicki A, Ng D, Yang X, Smith AB 3rd, Sodroski J, Freire E. Thermodynamics of binding of a low-molecular-weight CD4 mimetic to HIV-1 gp120. Biochemistry. 2006 Sep 12;45(36):10973-80. [2]. Singh IP, Chauthe SK. Small molecule HIV entry inhibitors: Part II. Attachment and fusion inhibitors: 2004-2010. Expert Opin Ther Pat. 2011 Mar;21(3):399-416. [3]. Zhao Q, Ma L, Jiang S, Lu H, Liu S, He Y, Strick N, Neamati N, Debnath AK. Identification of N-phenyl-N'-(2,2,6,6-tetramethyl-piperidin-4-yl)-oxalamides as a new class of HIV-1 entry inhibitors that prevent gp120 binding to CD4. Virology. 2005 Sep 1;339 [4]. Narumi, Tetsuo et al. CD4 mimics targeting the HIV entry mechanism and their hybrid molecules with a CXCR4 antagonist. Bioorganic & Medicinal Chemistry Letters (2010), 20(19), 5853-5858.