Regulatory

Don't mix boceprevir with certain HIV drugs: FDA

Last Updated: 2012-04-26 15:50:27 -0400 (Reuters Health)

WASHINGTON (Reuters) - U.S. drug regulators are changing the label on the recently approved protease inhibitor boceprevir (Victrelis, Merck & Co) for treatment of hepatitis C virus (HCV) to state that it should not be taken with some widely used drugs for HIV infection.

Co-administration of boceprevir, along with certain ritonavir-boosted 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," the U.S. Food and Drug Administration (FDA) said Thursday.

Ritonavir-boosted HIV protease inhibitors include ritonavir-boosted Reyataz (atazanavir), ritonavir-boosted Prezista (darunavir), and Kaletra (lopinavir/ritonavir).

The FDA advises, "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."

The FDA and Merck first warned about the issue back in February based on the results of a drug-drug interaction study, which showed that taking boceprevir with any one of the three ritonavir-boosted HIV protease inhibitors could reduce the desired blood levels of both medicines.

The FDA said it is changing the label for boceprevir also based on preliminary results of a small clinical trial presented last month at the 19th Conference on Retroviruses and Opportunistic Infections.

Merck has said it still plans a larger drug-interaction trial of boceprevir with other HIV drugs.

The FDA said it would communicate any new information about taking boceprevir together with the HIV drugs when it becomes available.