Tag Archives: abt-333

More options for Hepatitis C

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As noted in numerous blog entries (see below), there has been increasing availability of new and more effective treatments for Hepatitis C virus (HCV).  Two more drugs have promising results:

  • NEJM 2013; 368: 34-44
  • NEJM 2013; 368; 45-53

The first study provides encouragement with regard to sofosbuvir (previously known as GS-7977) which is a direct-acting nucleotide polymerase inhibitor targeting the NS5B polymerase.

In this open-label study, there were eight groups of patients.  Of 40 previously untreated patients (genotype 2 or 3), all patients received sofosbuvir (400 mg daily) for 12 weeks.  All 10 who received the study drug with ribavirin (& without interferon) and all 30 who received the study drug with ribavirin and peginterferon had a sustained virologic response (SVR) at 24 weeks.  Among patients with sofosbuvir monotherapy, 6 of 10 had a SVR.  Among HCV genotype 1 patients, 21 of 25 (84%) previously untreated patients had a SVR. The most common adverse effects were headache, fatigue, insomnia, rash and anemia.

The second study also was a phase 2a, open-label study for HCV genotype 1 non-cirrhotic patients using ABT-333 and ribavirin.  ABT-333 is a nonnucleoside NS5B polymerase inhibitor.  Results: 17 of 19 (89%) patients in group 1 (Rx with ABT-333, ribavrin, ABT-450, and ritonavir), 11 of 14 (79%) patients in group 2 (Rx with same drugs at lower doses of latter two drugs) had extended rapid virologic response.  SVR was achieved in 95% and 93% respectively.  Groups 1 and 2 were previously untreated.  Group 3 were patients who had either a null or partial response to previous treatment achieved a 47% SVR.  The most common adverse effects were abnormalities in liver function tests, headache, fatigue, insomnia, pruritus, nausea and rash.

Bottom-line:

These preliminary results suggest that Sofosbuvir is effective in all genotypes and may allow a short duration all-oral regimen.  ABT-333 similarly is effective in an all oral regimen in genotype 1 patients.

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