Faculty Bibliography

Telaprevir is a potent HCV NS3/4A protease inhibitor. A completed development program has demonstrated the superior efficacy of a regimen of telaprevir combined with pegylated interferon alfa and ribavirin (PR) over PR alone in patients with HCV genotype 1. In the ADVANCE trial in treatment-naive patients, 12 weeks of telaprevir, peginterferon alfa-2a and ribavirin followed by either 12 or 36 weeks of PR alone (depending upon extended rapid virologic response, or eRVR, i.e. HCV RNA undetectability at weeks 4 and 12), was associated with sustained virological response (SVR) in 75% of patients compared with 46% receiving PR for 48 weeks. The ILLUMINATE trial established the foundation for response-guided therapy in patients with eRVR. The REALIZE trial in treatment-experienced patients showed a gradient of SVR from prior relapsers (86%) to partial responders (57%) to null responders (31%), with rates of virologic failure and emergent resistance highest in the latter group. Incremental adverse effects of telaprevir include rash, anemia, pruritus, diarrhea, and nausea. Treatment naive patients and relapsers are eligible for response-guided therapy. Stopping rules of telaprevir-based treatment include HCV RNA > 1000 IU/ml at weeks 4 and 12.

Until recently, the standard of care (SOC) for patients with chronic hepatitis C virus (HCV) infection has consisted of a combination of pegylated interferon-alpha [corrected] plus ribavirin, administered for 24- to 48-weeks depending on the HCV genotype. The sustained virologic response rate for this SOC has been only about 50% in patients infected with genotype 1 HCV, the most prevalent genotype in Europe and North America. HCV therapy has been revolutionised recently by the approval of two direct-acting antiviral agents (DAA) against the NS3/4A serine protease for use in genotype 1 HCV, the ketoamide inhibitors boceprevir and telaprevir. The novel SOC marks the beginning of an extraordinary new era in HCV therapy. We review this new SOC with an emphasis on practical issues related to protease inhibitors, e.g. prescribing guidelines, futility rules and management of adverse events. We also give a perspective on what to expect in the coming years. Newer DAA with simplified dosing regimens and/or minimal toxicity which, when used in combination, will lead to viral eradication in most if not all CHC patients who undergo treatment. The novel agents in clinical development are paving the way for future interferon-sparing regimens.

Boceprevir and telaprevir are peptidomimetic serine protease inhibitors that have been recently approved for the treatment of HCV chronic infection. The addition of these drugs to the prior standard of care, pegylated interferon and ribavirin, improves sustained virological response rates for treatment-naive and treatment-experienced patients and shortens the duration of treatment for over half of treatment-naive patients. This review describes the clinical data supporting the approval and use of telaprevir and boceprevir, the algorithm for the use of these drugs, their adverse effects, as well as their important drug-drug interactions.

BACKGROUND: In patients with genotype 1 chronic hepatitis C infection, telaprevir (TVR) in combination with peginterferon and ribavirin (PR) significantly increased sustained virologic response (SVR) rates compared with PR alone. However, genotypic changes could be observed in TVR-treated patients who did not achieve an SVR. METHODS: Population sequence analysis of the NS3*4A region was performed in patients who did not achieve SVR with TVR-based treatment. RESULTS: Resistant variants were observed after treatment with a telaprevir-based regimen in 12% of treatment-naive patients (ADVANCE; T12PR arm), 6% of prior relapsers, 24% of prior partial responders, and 51% of prior null responder patients (REALIZE, T12PR48 arms). NS3 protease variants V36M, R155K, and V36M+R155K emerged frequently in patients with genotype 1a and V36A, T54A, and A156S/T in patients with genotype 1b. Lower-level resistance to telaprevir was conferred by V36A/M, T54A/S, R155K/T, and A156S variants; and higher-level resistance to telaprevir was conferred by A156T and V36M+R155K variants. Virologic failure during telaprevir treatment was more common in patients with genotype 1a and in prior PR nonresponder patients and was associated with higher-level telaprevir-resistant variants. Relapse was usually associated with wild-type or lower-level resistant variants. After treatment, viral populations were wild-type with a median time of 10 months for genotype 1a and 3 weeks for genotype 1b patients. CONCLUSIONS: A consistent, subtype-dependent resistance profile was observed in patients who did not achieve an SVR with telaprevir-based treatment. The primary role of TVR is to inhibit wild-type virus and variants with lower-levels of resistance to telaprevir. The complementary role of PR is to clear any remaining telaprevir-resistant variants, especially higher-level telaprevir-resistant variants. Resistant variants are detectable in most patients who fail to achieve SVR, but their levels decline over time after treatment.

Boceprevir or telaprevir plus ribavirin (RBV) and pegylated interferon-alpha (pegIFN-alpha) is the new standard-of-care therapy for patients who are chronically infected with genotype 1 hepatitis C virus (HCV). The addition of these protease inhibitors to the RBV/pegIFN-alpha combination regimen has significantly improved rates of sustained virologic response (SVR); however, the incidence of anemia has also increased significantly. Anemia can interfere with patients' quality of life, work productivity, and treatment adherence. Severe anemia can cause morbidity and even mortality. For the management of anemia during triple combination therapy, RBV dose reduction is recommended as an initial course of action. Retrospective analyses of carefully selected patient cohorts suggest that RBV dose reduction does not reduce SVR rates. However, this observation needs to be confirmed in prospective trials with cohorts that more accurately reflect the challenging patients treated in real-world practice. Adequate doses of RBV should be maintained during triple combination therapy, as phase II trials have demonstrated that RBV is essential for attaining optimal SVR rates and preventing viral breakthrough, relapse, and emergence of resistant variants. This roundtable addresses key points related to the management of anemia in the era of triple combination therapy, including the increasing problem of anemia, strategies for anemia management, and the importance of maintaining adequate RBV exposure as part of the HCV treatment regimen.

The HCV council 2011 convened 11 leading clinicians and researchers in hepatitis C virus from academic medical centers in the United States to provide a forum for the practical and comprehensive evaluation of current data regarding best practices for integrating new direct-acting antiviral agents into existing treatment paradigms. The council investigated 10 clinical practice statements related to HCV treatment that reflect key topical areas. Faculty members reviewed and discussed the data related to each statement, and voted on the nature of the evidence and their level of support for each statement. In this new era of DAAs, a comprehensive and critical analysis of the literature is needed to equip clinicians with the knowledge necessary to design, monitor, and modify treatment regimens in order to optimize patient outcomes.

BACKGROUND & AIMS: Little is known about factors associated with a sustained virologic response (SVR) among patients with hepatitis C virus (HCV) infection to treatment with protease inhibitors. METHODS: Previously untreated patients (from the Serine Protease Inhibitor Therapy 2 [SPRINT-2] trial) and those who did not respond to prior therapy (from the Retreatment with HCV Serine Protease Inhibitor Boceprevir and PegIntron/Rebetol 2 [RESPOND-2] trial) received either a combination of peginterferon and ribavirin for 48 weeks or boceprevir, peginterferon, and ribavirin (triple therapy) after 4 weeks of peginterferon and ribavirin (total treatment duration, 28-48 wk). A good response to interferon was defined as a >/= 1 log(10) decrease in HCV RNA at week 4; a poor response was defined as a <1 log(10) decrease. We used multivariate regression analyses to identify baseline factors of the host (including the polymorphism interleukin [IL]-28B rs12979860) associated with response. The polymorphism IL-28B rs8099917 also was assessed. RESULTS: In the SPRINT-2 trial, factors that predicted a SVR to triple therapy included low viral load (odds ratio [OR], 11.6), IL-28B genotype (rs 12979860 CC vs TT and CT; ORs, 2.6 and 2.1, respectively), absence of cirrhosis (OR, 4.3), HCV subtype 1b (OR, 2.0), and non-black race (OR, 2.0). In the RESPOND-2 trial, the only factor significantly associated with a SVR was previous relapse, compared with previous nonresponse (OR, 2.6). Most patients with rs12979860 CC who received triple therapy had undetectable levels of HCV RNA by week 8 (76%-89%), and were eligible for shortened therapy. In both studies, IL-28B rs12979860 CC was associated more strongly with a good response to interferon than other baseline factors; however, a >/= 1 log(10) decrease in HCV-RNA level at week 4 was associated more strongly with SVR than IL-28B rs12979860. Combining the rs8099917 and rs12979860 genotypes does not increase the association with SVR. CONCLUSIONS: The CC polymorphism at IL-28B rs12979860 is associated with response to triple therapy and can identify candidates for shorter treatment durations. A >/= 1 log(10) decrease in HCV RNA at week 4 of therapy is the strongest predictor of a SVR, regardless of polymorphisms in IL-28B.