Darunavir (Prezista)

Darunavir (Prezista) is an antiretroviral drug from the class known as protease inhibitors. Protease inhibitors block the activity of the HIV protease enzyme that HIV uses to break up large viral proteins so that new HIV particles can be formed. Inhibiting this action slows HIV replication and delays damage to the immune system. For more information on how protease inhibitors work, see Protease inhibitors in the section Ways of attacking HIV.        

Darunavir (formerly TMC114) was developed by the Belgian company Tibotec and designed to be active against HIV resistant to then-current 'first-generation' protease inhibitors. It was originally licensed in 2006 by the European Medicines Agency’s (EMEA) Committee for Medicinal Products for Human Use and the US FDA for use in highly treatment-experienced patients.

This recommendation was based on favourable results from the POWER study, a randomised comparison of darunavir/ritonavir with other ritonavir-boosted protease inhibitors in patients with experience of all three classes of antiretroviral drug available at the time the study began. Participants in this study had relatively high levels of protease inhibitor resistance.

Following the results from the TITAN study in 2008, in which DRV/r showed a clear advantage in treatment-experienced patients with less exposure to protease inhibitors, the EMEA expanded its licence to include use by patients with any prior ARV experience.

In 2008, the US approved darunavir’s use in ARV-naive patients, based on data from the ARTEMIS study. Darunavir was approved for once-daily first-line use in Europe in February 2009.

Response to darunavir does not appear to vary according to previous protease inhibitors use. Analysis of resistance in clinical studies have indicated HIV would need to accumulate up to eleven different mutations in the protease enzyme to become resistant to darunavir.