The FDA has notified healthcare professionals that drug interactions between the hepatitis C virus (HCV) protease inhibitor Victrelis (boceprevir; Merck) and certain ritonavir-boosted human immunodeficiency virus (HIV) protease inhibitors can potentially reduce the effectiveness of these medicines when they are used together. A drug-interaction study showed that taking Victrelis with ritonavir (Norvir) in combination with Reyataz (atazanavir; Bristol-Myers Squibb), Prezista (darunavir; Janssen Therapeutics), or Kaletra (lopinavir/ritonavir; Abbott) reduced the blood levels of the HIV medicines and Victrelis in the body.
In the study, Victrelis reduced mean trough concentrations of ritonavir-boosted Reyataz, Prezista, and Kaletra by 49%, 43%, and 59%, respectively. Mean reductions of 34–44% and 25–36% were observed in area under the curve (AUC) and peak concentration (Cmax) of Reyataz, Prezista, and Kaletra. Co-administration of ritonavir-boosted Reyataz with Victrelis did not alter the exposure (AUC) of Victrelis, but co-administration of Victrelis with Kaletra or ritonavir-boosted Prezista decreased the AUC of Victrelis by 45% and 32%, respectively.
The FDA and Merck are updating the Victrelis drug labeling to include information about these interactions. Victrelis is a HCV NS3/4A protease inhibitor indicated for the management of chronic hepatitis C genotype 1 infection in combination with other therapies. Reyataz, Prezista, and Kaletra are HIV protease inhibitors indicated for the treatment of HIV-1 infection. Healthcare professionals who have initiated Victrelis in combination with peginterferon alfa and ribavirin in HIV-HCV co-infected patients on fully suppressive antiretroviral therapy containing a ritonavir-boosted protease inhibitor should discuss these findings with those patients, and closely monitor those patients for HCV treatment response and for potential HCV and HIV virologic rebound.
For more information visit www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm291144.htm.