The use of unboosted darunavir in the setting of ritonavir intolerance: three case reports

To describe three patients with human immunodeficiency virus (HIV) who were successfully managed with unboosted darunavir (uDRV).

The three cases included one woman and two men aged 58, 54, and 51 years, respectively. All patients were HIV positive and unable to tolerate ritonavir-boosted protease inhibitors secondary to significant gastrointestinal intolerance. Unboosted darunavir was tolerated without any further issues when prescribed with an optimized antiretroviral (ARV) background regimen. Despite low darunavir (DRV) concentrations, all three patients achieved a virologic response.

Darunavir is a relatively well-tolerated ARV, but concurrent ritonavir administration has several disadvantages (e.g., dose-related hyperlipidemia, gastrointestinal intolerance, drug-drug interactions) which may decrease patient adherence. The use of uDRV may be particularly useful in patients with limited therapy options who are unable to tolerate ritonavir-boosted protease inhibitors. Therapeutic drug monitoring (TDM) was performed as unboosted DRV has a bioavailability of 37% and the virologic and immunologic response has only been demonstrated with ritonavirboosted DRV.

Successful use of uDRV may be an acceptable ARV option in carefully selected patients with limited treatment options, particularly when an optimized background regimen is included. Darunavir TDM should be strongly considered if uDRV is initiated.