Important drug interaction info.

Important drug interactions between Victrelis (boceprevir) and ritonavir-boosted human immunodeficiency virus (HIV) protease inhibitor drugs.

FDA Drug Safety Communication

Safety Announcement

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 (PDF - 67KB) disclaimer icon with information about this drug interaction study.

Additional Information for Patients

• Drug interactions between the hepatitis C virus (HCV) protease inhibitor Victrelis (boceprevir) and ritonavir used in combination with other human immunodeficiency virus (HIV) protease inhibitors 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 about Victrelis or HIV protease inhibitors.

• Patients should report side effects from the use of Victrelis or HIV protease inhibitors to the FDA MedWatch program, using the information in the "Contact FDA" box at the bottom of this page.

Additional Information for Healthcare Professionals

• Drug interactions between the hepatitis C virus (HCV) protease inhibitor Victrelis (boceprevir) and ritonavir-boosted atazanavir, lopinavir, and darunavir can potentially reduce the effectiveness of these medicines when co-administered.
• 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.
• Victrelis (boceprevir) and Incivek (telaprevir) were approved in May, 2011, each in combination with peginterferon alfa and ribavirin for treatment of genotype 1 chronic hepatitis C in adult patients with compensated liver disease. Neither NS3/4A protease inhibitor is approved for treatment of patients co-infected with HIV. Drug interaction data with telaprevir and ritonavir-boosted HIV protease inhibitors can be found in the Incivek drug label (PDF - 314KB). Information about clinical trials in HIV-HCV co-infected patients can be found at ClinicalTrials.gov.
• Healthcare professionals should report adverse events involving Victrelis or HIV protease inhibitors to the FDA MedWatch program using the information in the "Contact FDA" box at the bottom of this page.

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.

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