Antiviral drug advances in the treatment of human immunodeficiency virus (HIV) and chronic hepatitis C virus (HCV)

Antiviral therapy is recommended for all HIV infected individuals. Therefore, there is a continuous need for improvement and optimization of current therapy and the development of novel agents and drug classes. Fixed dose combinations (FDC) with the advantage of once daily dosing and improved tolerability and toxicity profiles are attractive options. The non-nucleoside reverse transcriptase inhibitor (NNRTI) based FDC of rilpivirine plus tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) (Complera®) and an extended release version of the NNRTI nevirapine, (Viramune XR®) were recent additions to the HIV armamentarium. In addition, the approval of the second integrase inhibitor, elvitegravir, and a novel pharmacoenhancer cobicistat is anticipated in 2012. These agents have been co-formulated with TDF and FTC as a single tablet and represent the first integrase inhibitor based complete FDC regimen. A new standard of care for the treatment of Chronic Hepatitis C (HCV) emerged in 2011 with the approval of the first antiviral drugs to directly inhibit HCV NS3/4A protease, telaprevir (Incivik®) and boceprevir (Victrelis®). Combined with peginterferon-alfa plus ribavirin they offer genotype-1 infected patients significantly improved sustained virologic response rates and the potential for shorter durations of therapy. HCV therapeutics will continue to evolve as there are several drugs in the protease inhibitor class and other classes such as NS5B polymerase inhibitors, NS5A inhibitors and cyclophilin inhibitors currently in development.

► Rilpivirine is a newly approved HIV NNRTI that is available in a fixed dose combination (FDC). ► The first FDC including a HIV integrase inhibitor, elvitegravir, is expected to be approved in 2012. ► The first hepatitis C virus (HCV) protease inhibitors (PIs) were approved in 2011. ► HCV PIs combined with pegylated interferon plus ribavirin significantly improves HCV cure rates. ► HCV PIs also carry increased side effects and significant drug–drug interactions.