FDA Drug Safety Communication: Updated information on drug interactions between Victrelis (boceprevir) and certain boosted HIV protease inhibitor drugs

[4-26-2012] The U.S. Food and Drug Administration (FDA) is notifying the public that co-administration of Victrelis (boceprevir), a hepatitis C virus (HCV) protease inhibitor, along with certain ritonavir-boosted human immunodeficiency virus (HIV) protease inhibitors, is not recommended at this time because of the possibility of reducing the effectiveness of the medicines, permitting the amount of HCV or HIV virus in the blood (viral load) to increase. Ritonavir-boosted HIV protease inhibitors include ritonavir-boosted Reyataz (atazanavir), ritonavir-boosted Prezista (darunavir), and Kaletra (lopinavir/ritonavir).

Patients should not stop taking any of their hepatitis C or HIV medicines without talking to their healthcare professional.  Patients should contact their healthcare professional with any questions or concerns. 

Healthcare professionals who started patients infected with both chronic HCV and HIV on Victrelis while the patient was taking antiretroviral therapy containing one of these ritonavir-boosted protease inhibitors should closely monitor patients for treatment response (no HCV virus detected in the blood) and for potential HCV or HIV virologic rebound (HCV or HIV virus is detected in the blood again after becoming undetectable).

Ritonavir is an HIV protease inhibitor that is taken as a small dose along with other HIV protease inhibitors in order to increase their levels in the blood and make them more effective. This is known as ritonavir boosting. 

In February 2012, FDA issued a Drug Safety Communication (DSC) regarding a drug-drug interaction study, which showed that taking Victrelis while taking any one of the three ritonavir-boosted HIV protease inhibitors could reduce the desired blood levels of both medicines. Because lower blood levels could lead to less effective treatment of HCV and HIV infections, FDA recommended that healthcare professionals closely monitor the treatment response of patients who might be taking these drug combinations.

There is limited information on the effectiveness of Victrelis and ritonavir-boosted HIV protease inhibitors when they are used together in patients co-infected with HIV and HCV.  A small clinical trial measured treatment outcomes of HIV-HCV co-infected patients whose HCV infection was treated with either peginterferon/ribavirin or boceprivir plus peginterferon/ribavirin and whose HIV infection was treated with ritonavir-boosted atazanavir, ritonavir-boosted darunavir, lopinavir/ritonavir, or raltegravir (Isentress). Persons who received boceprevir plus peginterferon/ribavirin were more likely to have undetectable HCV viral loads 12 weeks after completing HCV treatment than individuals who received peginterferon/ribavirin alone. Overall, seven patients had HIV virologic rebound, 3/64 randomized to receive boceprevir with peginterferon/ribavirin and 4/34 randomized to peginterferon/ribavirin alone. Preliminary results of this clinical trial were presented at the 19th Conference on Retroviruses and Opportunistic Infections on March 6, 2012. The clinical trial abstract is available here.

In light of both the findings of the drug-drug interaction study and the clinical trial, FDA has revised the Victrelis drug label to state that co-administration of Victrelis with ritonavir-boosted Reyataz (atazanavir), ritonavir-boosted Prezista (darunavir), or Kaletra (lopinavir/ritonavir) to patients infected with both chronic HCV and HIV is not recommended at this time.

FDA is aware that a larger clinical trial is planned that will evaluate HCV treatment with boceprevir and peginterferon/ribavirin in patients infected with both HCV and HIV who are also receiving HIV antiretroviral therapy containing ritonavir-boosted HIV protease inhibitors.  FDA will communicate any important new information about co-administration of these drugs in co-infected patients when it becomes available.