An Interferon-free combination of the protease inhibitor ABT-450 with Ritonavir ( ABT-450/r ), the nonnucleoside polymerase inhibitor ABT-333, and Ribavirin has showed efficacy against the hepatitis C virus ( HCV ) in a pilot study involving patients with HCV genotype 1 infection.
The addition of another potent agent, the NS5A inhibitor ABT-267, may improve efficacy, especially in difficult-to-treat patients.
This study was designed to evaluate multiple regimens of direct-acting antiviral agents and Ribavirin in patients with HCV genotype 1 infection who had not received therapy previously or who had no response to prior therapy with Pegylated Interferon and Ribavirin.
In this phase 2b, open-label study with 14 treatment subgroups, 571 patients without cirrhosis who had not received treatment previously or who had not had a response to prior therapy were randomly assigned to a regimen of ABT-450/r, combined with ABT-267 or ABT-333 or both, for 8, 12, or 24 weeks and received at least one dose of therapy.
All the subgroups but 1 also received Ribavirin ( dose determined according to body weight ).
The primary end point was sustained virologic response at 24 weeks after the end of treatment. The primary efficacy analysis compared rates between previously untreated patients who received three direct-acting antiviral agents and Ribavirin for 8 weeks and those who received the same therapy for 12 weeks.
Among previously untreated patients who received three direct-acting antiviral agents ( with the ABT-450/r dose administered as 150 mg of ABT-450 and 100 mg of Ritonavir ) plus Ribavirin, the rate of sustained virologic response at 24 weeks after treatment was 88% among those who received the therapy for 8 weeks and 95% among those who received the therapy for 12 weeks ( difference, -7 percentage points; P=0.24 ).
The rates of sustained virologic response across all treatment subgroups ranged from 83 to 100%.
The most frequent adverse events were fatigue, headache, nausea, and insomnia. Eight patients ( 1% ) discontinued treatment owing to adverse events.
In this phase 2b study, all-oral regimens of antiviral agents and Ribavirin were effective both in patients with HCV genotype 1 infection who had not received therapy previously and in those who had not had a response to prior therapy. ( Xagena )
Kowdley KV et al, N Engl J Med 2014; 370: 222-232