March 8, 2012
Two recently approved hepatitis C virus drugs are effective in patients co-infected with HIV, according to data presented Tuesday at the 19th Conference on Retroviruses and Opportunistic Infections in Seattle. The new studies involve the HCV protease inhibitors Victrelis (boceprevir) and Incivek (telaprevir).
The new results follow the announcement last month that Victrelis could lessen the efficacy of certain HIV protease inhibitors boosted by ritonavir. The HIV protease inhibitors use the same pathway as the new HCV drugs, so there is a potential for drug interactions, said Dr. Douglas Dietrich, professor of medicine at Mount Sinai School of Medicine in New York.
In a trial involving co-infected patients, 74 percent treated with Incivek, followed by standard HCV therapy ribavirin and interferon, were free of HCV 12 weeks after ending treatment, compared with just 45 percent on standard HCV therapy alone. Viral load did not rebound for any HIV patients on Incivek, which is made by Vertex Pharmaceuticals Inc. The more common side effects included itching, headache, nausea, rash (not severe), fever, and depression.
In the Victrelis trial, 60.7 percent taking it and standard HCV therapy were free of HCV 12 weeks after treatment, compared with 26.5 percent of those on standard HCV therapy alone. Three patients who took Victrelis and four who took only standard therapy had an increase in HIV.
"The drugs that are used to treat HIV have certain metabolic effects," said Eliav Barr, vice president of infectious diseases at Merck, maker of Victrelis. "You have to be careful not to mess with those drug levels."
Vertex said it is now enrolling participants in a Phase III trial investigating Incivek combination regimens among co-infected patients. Merck is conducting a number of Victrelis drug interaction studies and expects within months to start a larger trial in a broader range of HIV patients.