Acquired immunodeficiency syndrome (AIDS) is one of the most destructive epidemics in medical history. In 2009, the UNAIDS report estimated that 35 million people are living with human immunodeficiency virus (HIV) infection and AIDS, 25 million deaths have occurred, and 14 million children have been orphaned since the epidemic began in 1981. The discovery of HIV, the etiological agent for AIDS, led to the identification of a number of biochemical targets to combat this devastating disease. Among them, therapeutic inhibition of a proteolytic enzyme, HIV-1 protease, emerged as a critical drug-development target. Subsequent design and discovery of protease inhibitors (PIs) and their introduction into the highly active antiretroviral therapy (HAART), marked the beginning of a new era of management of HIV-1 infection and AIDS. HAART significantly improved the quality of life and life expectancy of patients. There is no cure for HIV/AIDS and long-term treatment has posed a serious challenge because of the emergence of multidrug-resistant HIV-1 variants. About 40-50% of those patients who initially achieved favorable viral suppression to undetectable levels experienced treatment failure. These drug-resistant HIV strains can be transmitted, raising further uncertainty with respect to future treatment options. In addition, PIs are faced with a number of serious limitations including, major toxicity, tolerance, and adherence to complex medical regimens. The development of a new generation of PIs effective against drug-resistant HIV and with minimum side effects, are vital to the future management of HIV/AIDS. Our collaborative research efforts to combat drug resistance, led to the development of darunavir which was first approved for treatment against drug-resistant HIV in June, 2006, and then received full approval for all HIV/AIDS patients including pediatric patients in December, 2008. While darunavir has become a front line therapy against HIV/AIDS, it is far from ideal as an effective long-term treatment option. During this project period, based upon X-ray crystal structures of complexes of darunavir or other PIs with HIV-1 protease, we designed and synthesized a diverse class of potent PIs with marked antiviral activity, and excellent drug-resistance profiles against multidrug-resistant HIV-1 strains. We have also developed tools and important 'backbone binding'design concepts to combat drug-resistance. Furthermore, we have discovered a number of small molecule nonpeptide structural leads for optimization. A recent inhibitor, GRL-0519, has consistently shown a 10-fold improvement of potency compared to darunavir against a panel of multidrug-resistant HIV-1 variants. This PI also exhibited 10-fold better dimerization inhibitory properties of HIV-1 protease. Our current proposed studies are now focused on design, synthesis, and evaluation of the next generation of PIs for clinical development. Our multidisciplinary research efforts integrate structure-based design, synthesis, protein-ligand X-ray crystallography, inhibition kinetics, molecular modeling, and in-depth virus and cell-biological studies.

Public Health Relevance

The 2010 UNAIDS reports 35 million people are living with HIV/AIDS (Acquired Immunodeficiency Syndrome). Progress against this global pandemic requires innovative improved treatment. This proposal details our design and synthesis of next generation protease inhibitors to address critical problems of existing therapy.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Method to Extend Research in Time (MERIT) Award (R37)
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Special Emphasis Panel (ZRG1-AARR-C (02))
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Fabian, Miles
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Purdue University
Schools of Arts and Sciences
West Lafayette
United States
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Ghosh, Arun K; Sean Fyvie, W; Brindisi, Margherita et al. (2017) Design, synthesis, X-ray studies, and biological evaluation of novel macrocyclic HIV-1 protease inhibitors involving the P1'-P2' ligands. Bioorg Med Chem Lett 27:4925-4931
Ghosh, Arun K; Rao, Kalapala Venkateswara; Nyalapatla, Prasanth R et al. (2017) Design and Development of Highly Potent HIV-1 Protease Inhibitors with a Crown-Like Oxotricyclic Core as the P2-Ligand To Combat Multidrug-Resistant HIV Variants. J Med Chem 60:4267-4278
Amano, Masayuki; Miguel Salcedo-Gómez, Pedro; Yedidi, Ravikiran S et al. (2017) GRL-09510, a Unique P2-Crown-Tetrahydrofuranylurethane -Containing HIV-1 Protease Inhibitor, Maintains Its Favorable Antiviral Activity against Highly-Drug-Resistant HIV-1 Variants in vitro. Sci Rep 7:12235
Benko, Zsigmond; Liang, Dong; Li, Ge et al. (2017) A fission yeast cell-based system for multidrug resistant HIV-1 proteases. Cell Biosci 7:5
Ghosh, Arun K; Brindisi, Margherita; Nyalapatla, Prasanth R et al. (2017) Design of novel HIV-1 protease inhibitors incorporating isophthalamide-derived P2-P3 ligands: Synthesis, biological evaluation and X-ray structural studies of inhibitor-HIV-1 protease complex. Bioorg Med Chem 25:5114-5127
Ghosh, Arun K; Cárdenas, Emilio L; Brindisi, Margherita (2017) Highly Stereoselective Asymmetric Aldol Routes to tert-Butyl-2-(3,5-difluorophenyl)-1-oxiran-2-yl)ethyl)carbamates: Building Blocks for Novel Protease Inhibitors. Tetrahedron Lett 58:4062-4065
Aoki, Manabu; Hayashi, Hironori; Rao, Kalapala Venkateswara et al. (2017) A novel central nervous system-penetrating protease inhibitor overcomes human immunodeficiency virus 1 resistance with unprecedented aM to pM potency. Elife 6:
Ghosh, Arun K; Rodriguez, Samuel (2016) An enantioselective synthesis of the C3-C21 segment of the macrolide immunosuppressive agent FR252921. Tetrahedron Lett 57:2884-2887
Aoki, Manabu; Hayashi, Hironori; Yedidi, Ravikiran S et al. (2016) C-5-Modified Tetrahydropyrano-Tetrahydofuran-Derived Protease Inhibitors (PIs) Exert Potent Inhibition of the Replication of HIV-1 Variants Highly Resistant to Various PIs, including Darunavir. J Virol 90:2180-94
Ghosh, Arun K; Brindisi, Margherita (2016) Achmatowicz Reaction and its Application in the Syntheses of Bioactive Molecules. RSC Adv 6:111564-111598

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