The Food and Drug Administration May 23 approved the protease inhibitor telaprevir to treat adults with genotype 1 chronic hepatitis C, in combination with standard therapy – a decision that comes less than 2 weeks after the agency okayed another protease inhibitor, boceprevir, for hepatitis C combination treatment.
"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," said Dr. Edward Cox, director of the Office of Antimicrobial Products in the FDA’s Center for Drug Evaluation and Research, in a statement.
Telaprevir’s approved indication is for treatment (in combination with peginterferon alfa and ribavirin) of genotype 1 chronic hepatitis C in adults "with compensated liver disease, including cirrhosis, who are [treatment naive] or who have been previously treated with interferon-based treatment, including prior null responders, partial responders, and relapsers."
At a meeting in April, the FDA’s antiviral drugs advisory panel unanimously supported the approval of telaprevir.
The FDA based its approval decision on the results of three phase III studies comparing treatment with peginterferon alfa and ribavirin (standard treatment) alone or in combination with telaprevir in about 2,250 treatment-naive and treatment-experienced adults.
The sustained virologic response (SVR) rate was 20%-45% higher among patients on telaprevir plus standard treatment, compared with those on standard treatment, according to the FDA statement announcing the approval.
Fewer than half of the patients responded to standard treatment with peginterferon alfa and ribavirin, which is administered for 48 weeks. However, the telaprevir studies indicated that treatment with telaprevir can be shortened to 24 weeks, "in most patients," according to the FDA, which noted that 60% of previously untreated patients achieved an early response after 24 weeks of treatment, with an SVR of 90%.
The recommended dosing is 750 mg of telaprevir taken three times a day, with food. It is administered with peginterferon alfa and ribavirin for 12 weeks, "followed by a response-guided regimen of either 12 or 36 additional weeks of peginterferon alfa and ribavirin depending on viral response and prior response status," according to the label.
The most commonly reported side effects associated with telaprevir in clinical trials included rash (which can be severe and treatment limiting), anemia, nausea, fatigue, headache, diarrhea, pruritus, and anal or rectal irritation and pain. Rash can be serious and may require stopping treatment with telaprevir or all three drugs, the FDA statement said.
Vertex Pharmaceuticals will market telaprevir as Incivek. Merck will market boceprevir as Victrelis, which the FDA approved May 13.