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High Response Rates Reported With Hepatitis C Vaccines in Phase II Trial
Three investigational direct-acting antivirals (DAAs) — ABT-267, ABT-333, and ABT-450/r (AbbVie) — have shown high sustained viral response (SVR) rates against genotype 1 (GT1) hepatitis C virus (HCV) infection in a phase IIb trial. SVRs of greater than 90% were achieved in treatment-naïve patients and in patients who had previously failed treatment with pegylated interferon (peg-IFN) and ribavirin (null responders).
The study’s objective was to assess the safety and efficacy of the combination of ABT-450/r (dosed 100/100 to 200/100 mg once daily), ABT-267 (25 mg once daily), and ABT-333 (400 mg twice daily) plus ribavirin in non-cirrhotic, treatment-naïve patients and in prior peg-IFN/ribavirin null responders after 8, 12, and 24 weeks of treatment. Enrollment was open to GT1-infected patients regardless of interleukin (IL)-28B host genotype.
Among the treatment-naïve patients, 99% achieved SVR at 12 weeks (SVR12), and 96% achieved SVR at 24 weeks (SVR24). Among the null responders, 93% achieved both SVR12 and SVR24.
Comparable SVR24 rates were also seen in treatment-naïve patients and in null responders across HCV subtypes, IL-28B host genotypes, baseline HCV-RNA levels, and severity of fibrosis.
Of the 247 patients included in this analysis, four (1.6%) discontinued treatment because of drug-related adverse events (AEs). Serious AEs occurred in four patients (1.6%), with one event (arthralgia) considered possibly drug-related. Other AEs (reported in more than 10% of patients) included headache, fatigue, nausea, insomnia, and diarrhea. Six patients experienced grade-3 or -4 laboratory abnormalities in total bilirubin, and one patient experienced alanine aminotransferase (ALT) abnormalities; all events resolved with continued dosing.
The triple-DAA combination is currently being studied in phase III clinical trials.
There is currently no vaccine for HCV infection.
Source: Abbvie; April 23, 2013.