Coadministration of boceprevir with ritonavir-boosted HIV protease inhibitors could reduce drugs' effectiveness

FDA has notified healthcare professionals and patients that drug interactions between the hepatitis C virus (HCV) protease inhibitor boceprevir (Victrelis, Merck) and certain ritonavir-boosted human immunodeficiency virus (HIV) protease inhibitors (atazanavir, lopinavir, darunavir) can potentially reduce the effectiveness of these drugs when they are used together.

FDA will be updating the boceprevir drug label to include information about these drug interactions.

In a company press release, Merck said that it has informed US physicians of the results of a recent pharmacokinetic study evaluating drug interactions between boceprevir, the company's oral HCV NS3/4A protease inhibitor, and ritonavir-boosted HIV protease inhibitors in 39 healthy volunteers.

COINFECTED PATIENTS

The safety and efficacy of boceprevir has not been established in patients coinfected with HIV and HCV. Merck does not recommend the coadministration of boceprevir and ritonavir-boosted HIV protease inhibitors.

"Though Victrelis is not indicated for the treatment of chronic HCV in those who are also infected with HIV, we recognize that some physicians have prescribed or may be considering prescribing Victrelis for patients taking ritonavir-boosted HIV protease inhibitors," Robin Isaacs, vice president, clinical research, infectious diseases, Merck Research Laboratories, said in the company press release.

"We felt it was important to share these data as part of our commitment to patient safety and transparency. What is most critical to remember is that all patients taking medicines for chronic HCV or HIV, or both, should not discontinue their medication regimens without first consulting with their physicians," Isaacs said.

In addition to notifying regulatory agencies of these results, Merck has informed the French National Agency for Research on AIDS and Viral Hepatitis (ANRS) and the AIDS Clinical Trials Group (ACTG), 2 organizations with whom Merck is collaborating on HCV/HIV coinfection clinical trials. Investigational studies evaluating the effectiveness and safety of boceprevir in patients coinfected with chronic HCV genotype 1 and HIV-1 are ongoing.

CLOSE MONITORING NEEDED

Healthcare professionals who have started patients infected with both chronic HCV and HIV on boceprevir 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.

Healthcare professionals and patients are encouraged to report adverse events or side effects related to the use of these products to FDA's MedWatch Safety Information and Adverse Event Reporting Program: