August 14, 2013
Atif Zaman, MD, MPH reviewing Zeuzem S et al. N Engl J Med 2013 Aug 15.
Despite promising findings, including higher response rates with inclusion of ribavirin in a triple-therapy regimen, response rates are still too low in this group to forgo interferon. Atif Zaman, MD, MPH
Interferon-free regimens should be available soon for hepatitis C virus (HCV) genotype 2 infection and probably genotype 3 infection. For now, the next-generation regimen for genotype 1 infection will be shorter and more tolerable but will still include interferon.
To continue the search for an effective, interferon-free regimen for HCV genotype 1 infection, researchers conducted an industry-funded, multicenter, randomized, open-label, phase IIb study in 362 treatment-naive patients. Patients received faldaprevir (120 mg once daily) plus deleobuvir (600 mg 2 or 3 times daily) with or without ribavirin (1000–1200 mg daily) for 16, 28, or 40 weeks. The primary endpoint was sustained virologic response at 12 weeks posttreatment (SVR12).
SVR12 did not differ by treatment duration (16 weeks, 59%; 28 weeks, 59%; 40 weeks, 52%) or by deleobuvir dose (69% for twice daily and 59% for three times daily). SVR12 was higher in ribavirin users versus nonusers (59% vs. 39%, P=0.03). SVR12 rates were numerically higher in patients with genotype 1b versus 1a (range across treatment groups, 56% to 85% vs. 11% to 47%) and in patients with IL28B genotype CC versus non-CC (range across treatment groups, 58% to 84% vs. 33% to 64%). Of 75 patients with virologic breakthrough, 73 had resistant HCV variant strains. Discontinuation rates ranged from 5% to 25% across treatment groups; the most common adverse events were rash, photosensitivity, nausea, vomiting, and diarrhea.
We are getting closer to an interferon-free regimen for genotype 1 hepatitis C virus infection, but we are not there yet. Ribavirin will likely still be needed as a part of the regimen. Also, multiple interferon-free regimens might be required, with choice of regimen based on predictors of response such as genotype 1 subtype and IL28B status. Finally, until their sustained virologic response rates approach 80%, interferon-free regimens will likely only be an option for patients for whom interferon-based regimens are intolerable or contraindicated.
Zeuzem S et al. Faldaprevir and deleobuvir for HCV genotype 1 infection. N Engl J Med 2013 Aug 15; 369:630. (http://dx.doi.org/10.1056/NEJMoa1213557)