According to the WHO statistics, over 38 million people in the world are living with HIV. Among them, more than 7 million are unaware of being infected, and only two-thirds of HIV-positive people have access to antiretroviral therapy. These numbers clearly demonstrate the range of the HIV/AIDS epidemic, as well as the necessity to make up for the lack of awareness and to broaden the prevention and treatment options. To stress the importance of combating HIV and to bring attention to existing HIV/AIDS-related issues, the WHO and UNAIDS mark World AIDS Day every year on December 1st. This year’s specific theme, “Global solidarity and shared responsibility,” emphasizes the acute need to unite the efforts of the international community to curb the infection spread and to cope with its consequences.
Despite numerous challenges that still exist, significant advances in managing HIV have recently been achieved. The development of the combination antiretroviral therapy (cART) [1-4] has enabled reducing the viral load in HIV-infected people, thus hindering progression to AIDS and preventing HIV transmission to others. This approach is based on combination of multiple drugs with different activity types in a single HIV treatment regimen, with the choice from about 50 approved HIV medications . The existing drugs may be split into seven classes  with different viral targets and active substances:
- nucleoside reverse transcriptase inhibitors (NRTIs), e.g., abacavir, zidovudine, emtricitabine;
- non-nucleoside reverse transcriptase inhibitors (NNRTIs), e.g., nevirapine, efavirenz, doravirine;
- protease inhibitors (PIs), e.g., atazanavir, fosamprenavir, darunavir;
- integrase inhibitors (INSTIs), e.g., raltegravir, dolutegravir;
- CCR5 antagonists, e.g., maraviroc;
- fusion inhibitors, e.g., enfuvirtide;
- post-attachment inhibitors, e.g., ibalizumab-uiyk.
NRTIs, PIs, and INSTIs block enzymes that HIV needs to replicate: reverse transcriptase [7,8], protease , and integrase, respectively. NNRTIs bind to reverse transcriptase and modify it, thereby also hindering viral replication. Other drug classes prevent HIV from entering the immune system cells.
Fig. 1. Examples of antiretroviral drugs
The present diversity of anti-HIV medicines has taken decades of targeted research studies, however, the existing treatment is only a measure to control the virus and turn the deadly infection into a manageable chronic health condition. Along with the global necessity to find a genuine cure, the question remains how to overcome the present limitations of cART. The toxicity of many antiretroviral drugs, arising adverse side effects, as well as developing resistance to HIV medicines and long-term drug compliance generate some critical issues (see  and references therein).
One possible research direction consists in probing compounds similar to known approved drugs and isolating less toxic ones with a longer-lasting performance. This approach allows improving the cART strategy both qualitatively and quantitatively by extending variability and, hence, the number of possible drug combinations. Another method supposes discovery of entirely new agents and mechanisms of action. Given that the HIV life cycle includes at least 17 different stages at which the virus could be potentially inhibited , the search for new HIV drug classes seems reasonable. An especially desirable scientific result would be a drug capable of eliminating HIV latent reservoirs in tissue organs; the discovery of such a mechanism will most likely mean a victory over the virus. Recently reported finding of Drug-S , which can cross the blood-brain barrier and effectively inhibit viral infection and replication, is a significant achievement; however, the drug is neurotoxic and requires further studies.
The ultimate goal of defeating HIV and AIDS motivates the continuous search for novel medicines and strategies, and it is a small-molecule drug design for antiretroviral treatment that can provide a promising course to obtain expected results.
To support the World AIDS Day 2020 with its targeted products Life Chemicals offers a set of Anti-HIV Screening Libraries, including:
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- Maenza, J., Charles Flexner, C. (1998). Combination Antiretroviral Therapy for HIV Infection. Am Fam Physician 57(11):2789-2798.https://www.aafp.org/afp/1998/0601/p2789.html
- Pomerantz, R.J.; Horn, D.L. (2003). Twenty years of therapy for HIV-1 infection. Nat Med. 9, 867-873. DOI: 10.1038/nm0703-867
- Arts, E. J., & Hazuda, D. J. (2012). HIV-1 antiretroviral drug therapy. Cold Spring Harbor perspectives in medicine, 2(4), a007161. DOI: 10.1101/cshperspect.a007161
- Maeda, K., Das, D., Kobayakawa, T., Tamamura, H., & Takeuchi, H. (2019). Discovery and Development of Anti-HIV Therapeutic Agents: Progress Towards Improved HIV Medication. Curr. Top. Med. Chem., 19(18), 1621–1649. DOI: 10.2174/1568026619666190712204603
- Xavier Ruiz, F., & Arnold, E. (2020). Evolving understanding of HIV-1 reverse transcriptase structure, function, inhibition, and resistance. Current Opinion in Structural Biology, 61, 113–123. DOI: 10.1016/j.sbi.2019.11.011
- Wang, Y., De Clercq, E., & Li, G. (2019). Current and emerging non-nucleoside reverse transcriptase inhibitors (NNRTIs) for HIV-1 treatment. Expert Opinion on Drug Metabolism & Toxicology. 15:10, 813-829, DOI: 10.1080/17425255.2019.1673367
- Voshavar, C. Protease inhibitors for the treatment of HIV/AIDS: Recent advances and future challenges. (2019). Curr. Top. Med. Chem., 19(18), 1571-1598. DOI: 10.2174/1568026619666190619115243
- Saha, M., & Bhattacharya, S. (2019). Recent Developments in the Medicinal Chemistry for New Small-Molecule Therapeutics to Treat HIV-AIDS. Curr. Top. Med. Chem., 19(18), 1569–1570. DOI: 10.2174/156802661918191009110427
- Mitsuya, H., Yarchoan, R., Kageyama, S. and Broder, S. (1991), Targeted therapy of human immunodeficiency virus‐related disease. The FASEB Journal, 5: 2369-2381. DOI: 10.1096/fasebj.5.10.1712326
- Agas, A., Schuetz, H., Mishra, V., Szlachetka, A. M., & Haorah, J. (2019). Antiretroviral drug-S for a possible HIV elimination. Int. j. physiol. pathophysiol. pharmacol. 11(4), 149–162.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6737427/