The US Food and Drug Administration (FDA) reported Wednesday that the 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.
This was based on results of a pharmacokinetic study released by Merck, the developer and manufacturer of Victrelis.
A summary of the data revealed:
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.
In a Merck news release Monday, the company reports that these drug interactions may be clinically significant for patients infected with both chronic HCV and HIV by potentially reducing the effectiveness of these medicines when coadministered. Victrelis is not indicated for use in patients who are infected with both HIV-1 and chronic HCV. The safety and efficacy of Victrelis (boceprevir) has not been established in this coinfected population. Merck does not recommend the coadministration of Victrelis and ritonavir-boosted HIV protease inhibitors.
The FDA advises patients not to stop taking their treatment and to discuss any concerns with their physician.
In addition, the agency advises health providers to closely monitor patients infected with both chronic HCV and HIV on Victrelis and antiretroviral therapy containing a ritonavir-boosted protease inhibitor for HCV treatment response and for potential HCV and HIV virologic rebound.
Victrelis was approved for the treatment of Hepatitis C last May, as was rival Vertex Pharmaceutical’s Hep C drug, Incivek.
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