A difficult-to-treat group of patients—those with HCV infection who have received a liver transplant—can now achieve high rates of sustained virologic response (SVR), according to new findings from the phase II CORAL-1 study. The trial used a combination regimen of ombitasvir, ABT-500, ritonavir, dasabuvir and ribavirin.

“Patients who receive a liver transplant for hepatitis C have lower survival than patients transplanted for other causes of cirrhosis,” explains Paul Kwo, an author of the study. “Patients with hepatitis C who receive a liver transplant have a 20–30% chance of developing recurrent cirrhosis within 5 years.” The typical treatment for these patients is based on interferon, which has a low response rate, carries the risk of rejection and has poor tolerability, leading Kwo and colleagues to investigate an alternative approach.

The CORAL-1 study included 34 patients with recurrent HCV genotype 1 infection who had received a liver transplant and had no fibrosis or mild fibrosis. A single-arm design was used to ensure the maximum opportunity for SVR in this historically difficult-to-treat group of patients. For 24 weeks, the participants received 25 mg of ombitasvir, 150 mg of ABT-500 and 100 mg of ritonavir daily, as well as 250 mg of dasabuvir twice daily and ribavirin. At 12 weeks and 24 weeks after completing the treatment, 33 patients achieved SVR, giving an SVR rate of 97%. One patient stopped treatment due to adverse events, but had achieved SVR. The treatment was well-tolerated, with participants reporting mild adverse events such as fatigue, headache and cough. “These findings suggest we may now be able to remove post-liver-transplant patients from the 'difficult-to-treat' or 'special population' designation,” says Kwo.

Following these positive results, the study is now being expanded to include patients with more advanced fibrosis (including cirrhosis). The team are also planning to explore the efficacy of a 12-week treatment duration and a ribavirin-free regimen in patients with HCV genotype 1b and no cirrhosis. “It is hoped that we will be able to refine this regimen further while preserving efficacy to give all post-transplant HCV-infected individuals the same opportunity to achieve SVR as those who have not undergone transplantation,” concludes Kwo.