The FDA has approved telaprevir (Incivek, Vertex), the second direct acting protease inhibitor to be granted agency approval this month to treat adults with chronic hepatitis C infections.
The first, boceprevir (Victrelis, Merck), was approved on May 13. Both drugs were approved as add-on therapies to be used with the standard treatment regimen of peginterferon alfa and ribavirin.
“With the approval of Incivek, there are now two important new treatment options for hepatitis C that offer a greater chance at a cure for some patients with this serious condition,” Edward Cox, MD, MPH, director of the FDA’s Office of Antimicrobial Products, said in a press release.
“The availability of new therapies that significantly increase responses while potentially decreasing the overall duration of treatment is a major step forward in the battle against chronic hepatitis C infection,” Cox said.
Telaprevir is indicated for adult patients with genotype 1 hepatitis C that have never before received interferon-based drug therapy for their infection or who have failed treatment or relapsed.
Dosing consists of two 375-mg tablets taken three times a day with standard dose peginterferon and ribavirin for 24 to 48 weeks, depending on virologic responses.
Data from phase-3 clinical trials indicate that telaprevir boosted sustained virologic response rates above 70% and up to 90% in treatment naïve patients. However, about half of previous null responders did not achieve a sustained response and had telaprevir resistance-associated substitutions emerge.
Telaprevir’s efficacy in patients who have previously failed therapy with a regimen that includes the drug or another hepatitis C protease inhibitor has not yet been established.
The FDA advisory committee that recommended telaprevir’s approval expressed concerns about the potential for severe life-threatening skin reactions. Three patients who took telaprevir in clinical trials developed Stevens-Johnson syndrome.
Rash and pruritus were common side effects, occurring in more than half of patients, a rate about double of that in the control group.