GRL-04810 and GRL-05010, Difluoride-Containing Nonpeptidic HIV-1 Protease Inhibitors (PIs) That Inhibit the Replication of Multi-PI-Resistant HIV-1 In Vitro and Possess Favorable Lipophilicity That May Allow Blood-Brain Barrier Penetration

We designed, synthesized, and identified two novel nonpeptidic human immunodeficiency virus type 1 (HIV-1) protease inhibitors (PIs), GRL-04810 and GRL-05010, containing the structure-based designed privileged cyclic ether-derived nonpeptide P2 ligand, bis-tetrahydrofuranylurethane (bis-THF), and a difluoride moiety, both of which are active against the laboratory strain HIV-1(LAI) (50% effective concentrations [EC(50)s], 0.0008 and 0.003 mu M, respectively) with minimal cytotoxicity (50% cytotoxic concentrations [CC(50)s], 17.5 and 37.0 mu M, respectively, in CD4(+) MT-2 cells). The two compounds were active against multi-PI-resistant clinical HIV-1 variants isolated from patients who had no response to various antiviral regimens. GRL-04810 and GRL-05010 also blocked the infectivity and replication of each of the HIV-1NL4-3 variants selected by up to 5 mu M lopinavir (EC(50)s, 0.03 and 0.03 mu M, respectively) and atazanavir (EC(50)s, 0.02 and 0.04 mu M, respectively). Moreover, they were active against darunavir (DRV)-resistant variants (EC50 in 0.03 to 0.034 mu M range for GRL-04810 and 0.026 to 0.043 mu M for GRL-05010), while DRV had EC(50)s between 0.02 and 0.174 mu M. GRL-04810 had a favorable lipophilicity profile as determined with the partition (log P) and distribution (log D) coefficients of -0.14 and -0.29, respectively. The in vitro blood-brain barrier (BBB) permeability assay revealed that GRL-04810 and GRL-05010 may have a greater advantage in terms of crossing the BBB than the currently available PIs, with apparent penetration indexes of 47.8 x 10(-6) and 61.8 x 10(-6) cm/s, respectively. The present data demonstrate that GRL-04810 and GRL-05010 exert efficient activity against a wide spectrum of HIV-1 variants in vitro and suggest that two fluorine atoms added to their bis-THF moieties may well enhance their penetration across the BBB.