Abbott Laboratories, a global healthcare company, has released details on its phase III hepatitis C registration program following promising results from its phase IIb clinical trial, known as Aviator.

The phase III clinical trials are designed to evaluate safety and efficacy of a 12-week regimen of three direct acting antivirals (DAA), with and without ribavirin, for the treatment of HCV in genotype 1 (GT1) non-cirrhotic, treatment-naīve and treatment-experienced patients. An additional phase III trial will study triple-DAAs, with ribavirin, in patients with cirrhosis for 12 or 24 weeks.

The phase III program, which is currently open for enrollment, will include more than 2,000 patients with HCV genotype 1, with trial sites in 29 countries. The DAAs in the studies include ABT-450/r (protease inhibitor and ritonavir), ABT-267 (NS5A inhibitor) and ABT-333 (non-nucleoside polymerase inhibitor). Treatment duration will be 12 weeks in non-cirrhotic patients, and 12 or 24 weeks in cirrhotic patients. All patients will be followed for 48 weeks post-treatment. Co-formulated tablets of ABT-450/r and ABT-267 will be used in the phase III trials.

"Abbott is committed to investigating a short-course HCV therapy without the use of interferon to achieve high SVR rates," said Scott Brun, M.D., divisional vice president, infectious disease development, Abbott. "Our trial enrollment strives to reflect a broad range of populations, including those that have been difficult to treat. We have been very encouraged by the data from the phase II studies, and look forward to confirming the findings in our phase III program."

Top-line intent-to-treat results from the 12-week, triple-DAA regimens with ribavirin found that 97.5% (77 of 79) of treatment-naīve GT1 patients and 93.3% (42 of 45) in GT1 null responder patients achieved SVR.