ORLANDO, Fla. — Viral breakthrough during the interferon/ribavirin phase of hepatitis C triple therapy was associated with genotype 1a and advanced liver fibrosis, similar to findings in previous clinical trials, according to study data presented here at Digestive Disease Week.
“We’ve noticed that there are patients who were experiencing viral breakthrough later in treatment,” Kali Zhou, MD, a resident in the department of medicine at the University of California, Los Angeles, told Infectious Disease News. “We did see later viral breakthrough in clinical trials, but we haven’t evaluated whether the characteristics of our breakthrough patients were similar to those who broke through in clinical trials.”
Zhou and colleagues conducted a retrospective analysis that included 55 patients who were treated from June 2011 to June 2012 and evaluated characteristics of patients who experienced viral breakthrough. Patients were treated with either boceprevir (Victrelis, Merck) or telaprevir (Incivek, Vertex).
Nine patients had viral breakthrough and all of those received telaprevir. Eight of those patients broke through during the interferon/ribavirin phase of treatment, with a mean time to breakthrough of 21.3 weeks. Six patients had genotype 1a, and six of the patients had stage 3-4 fibrosis on liver biopsy. Six patients were prior null responders and one was a prior relapse. Resistance patterns were detected in six of eight patients who underwent resistance testing, and the six patients also had cross-resistance to boceprevir.
“Right now, the recommended frequency of testing viral load is weeks 4, 12, 24 and 48 for patients receiving telaprevir, and one more test at week 8 for patients receiving boceprevir,” Zhou said. “Because most of the patients broke through after week 12, patients at high risk should probably have viral load testing monthly.”
Zhou K. #Sa1040. Characteristics of Viral Breakthrough With Direct Acting Agents for Chronic Hepatitis C Treatment in Clinical Practice. Presented at: Digestive Disease Week; May 18-21, 2013; Orlando, Fla.
Disclosure: Zhou reports no relevant financial disclosures.