After a decade of slow progress in the treatment of HIV infection, the last few years have seen dramatic advances in the development of antiretroviral drugs (ARV). This now offers extended patient survival and improved quality of life. Various new medications (such as protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitor (NNRTIs), when combined with older nucleoside reverse transcriptase inhibitors (NRTIs), have the potential to reduce HIV replication.
The concurrent development of new anti-fungal and antibacterial drugs allows clinicians to hold at bay the most common (and once fatal) opportunistic infections. Determination of CD4+ T lymphocyte counts, and more recently the viral load has allowed more accurate monitoring of disease progression and guide targeted therapy. Technologically advanced tests such as HIV genotyping help identify mutations that confer drug resistance and so give a physician the ability to rationally use existing antiretroviral drugs.
Theoretically the multiple steps in replication of HIV provide opportunities for intervention. Therapeutic regimens may be directed at one or several of the following stages essential for viral replication. (See Fig 5):
Attachment of HIV to host cell
Reverse transcription of viral RNA to DNA
Integration of pro-viral DNA into host genome
Expression of the viral gene after it has been integrated into host cell DNA including the process of transcription of more viral RNA and the translation of viral proteins.
Processing and post-translational modification of protein products of the virus.
Figure 4: Sites of Anti-retroviral (ARV) drugs action