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FDA Drug Safety Communication: Important Drug Interactions Between Victrelis (Boceprevir) and Ritonavir-Boosted Human Immunodeficiency Virus (HIV) Protease Inhibitor Drugs

February 8, 2012

Safety Announcement

Facts About Victrelis (Boceprevir) and HIV Protease Inhibitors

  • Victrelis is a hepatitis C virus (HCV) protease inhibitor used with the medicines peginterferon alfa and ribavirin to treat chronic (long-lasting) hepatitis C infection in adults who have not been treated before or who have failed previous treatment.
  • HIV protease inhibitors are a class of anti-viral drugs used to treat HIV infection.
  • Ritonavir is an HIV protease inhibitor used to "boost" other HIV protease inhibitors, increasing their levels in the blood and making them more effective.
The U.S. Food and Drug Administration (FDA) is notifying healthcare professionals and patients that drug interactions between the hepatitis C virus (HCV) protease inhibitor Victrelis (boceprevir) and certain ritonavir-boosted human immunodeficiency virus (HIV) protease inhibitors (atazanavir, lopinavir, darunavir) can potentially reduce the effectiveness of these medicines when they are used together.

Patients should not stop taking any of their medicines without talking to their healthcare professional. Patients should contact their healthcare professional if they have any questions or concerns.

Healthcare professionals who have started patients infected with both chronic HCV and HIV on Victrelis and antiretroviral therapy containing a ritonavir-boosted protease inhibitor should closely monitor patients for HCV treatment response and for potential HCV and HIV virologic rebound.

A drug interaction study showed that taking boceprevir (Victrelis) with ritonavir (Norvir) in combination with atazanavir (Reyataz) or darunavir (Prezista), or with Kaletra (lopinavir/ritonavir) reduced the blood levels of the HIV medicines and boceprevir in the body (see "Data Summary" below). FDA will be updating the Victrelis drug label to include information about these drug interactions.

Merck and Company has issued a Dear Healthcare Professional letter with information about this drug interaction study.

Additional Information for Patients

Additional Information for Healthcare Professionals

Data Summary

A pharmacokinetic study evaluated drug interactions between boceprevir (Victrelis) and ritonavir-boosted human immunodeficiency virus (HIV) protease inhibitors in healthy volunteers (n=39). In the study, concomitant administration of Victrelis (boceprevir) with ritonavir (Norvir) in combination with atazanavir (Reyataz), darunavir (Prezista), or with lopinavir/ritonavir (Kaletra) resulted in reduced exposures of the HIV medicines and boceprevir. Victrelis reduced mean trough concentrations of ritonavir-boosted atazanavir, lopinavir, and darunavir by 49, 43 and 59 percent, respectively. Mean reductions of 34 to 44 percent and 25 to 36 percent were observed in area under the curve (AUC) and peak concentration (Cmax) of atazanavir, lopinavir, and darunavir. Co-administration of ritonavir-boosted atazanavir with Victrelis did not alter the exposure (AUC) of boceprevir, but co-administration of Victrelis with lopinavir/ritonavir or ritonavir-boosted darunavir decreased the AUC of boceprevir by 45 and 32 percent, respectively.

Related Information

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