HCV Treatment Success: Early Response vs. Genotype
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There is much debate among experts about the duration of treatment required for treating the Hepatitis C virus (HCV). As prescribed by physicians worldwide, the standard duration of a prescription for pegylated interferon (Pegasys or PegIntron) plus weight-based ribavirin differs depending on the patient’s genotype. However, recently announced research suggests that duration of treatment is best based on the individual’s virological response at specific intervals rather than their genotype.
The standard course of treatment is established by analyzing the results of large clinical trials. As determined by computational averages, these trials provide analysts with an ideal regimen for the population as a whole. In general, the standard duration of treatment is 24 weeks for HCV genotypes 2 and 3, and 48 weeks for HCV genotype 1. Despite this traditionally used model for determining treatment length, researchers have been finding that the best approach for Hepatitis C may veer away from this standardization and lean towards individual customization.
Historically, HCV genotype is the single most important predictor of a person’s outcome from treatment with pegylated interferon and ribavirin. Defined as a sustained viral response, a successful outcome is when the virus is undetectable in the blood six months after treatment ends.
The statistics consistently demonstrate that while about 50 percent of those with genotype 1 will achieve a sustained virologic response (SVR), between 70 and 90 percent of patients with genotype 2 or 3 will achieve SVR. Regardless of HCV genotype, experts have observed that patients who respond quickly to drug treatment are also more likely to be cured by them. Because pegylated interferon and ribavirin therapy is costly and carries the risk of serious side effects, scientists are continuously exploring new ways of predicting SVR so that the length of treatment can be customized for each patient.
The week of April 23-27, 2008, the 43rd annual meeting of the European Association for the Study of the Liver was held in Milan, Italy. Along with the myriad of revelations at this meeting, researchers presented a retrospective analysis of three randomized trials that demonstrated a rapid virologic response (RVR) to be superior to HCV genotype at predicting sustained virologic response.
Upon studying the outcomes of three trials, which, collectively, followed nearly 1,400 people receiving treatment for HCV, analysts compared these two factors for predicting SVR:
- HCV genotype
- RVR – defined as undetectable viral load after only four weeks of treatment
Among those achieving RVR in just four weeks of treatment, most (over 86 percent) achieved SVR independent of their HCV genotype. The value of this information applies to the scientists who calculate treatment time and to the physicians administering pegylated interferon and ribavirin treatment for HCV. The researchers recommended including RVR into the computations for treatment duration. In addition, they advise using an individual’s response to treatment after just one month to customize drug regimens regardless of genotype.
The debate over exactly how much medication for how long continues to churn in the Hepatitis C scientific community. By varying the treatment duration based on an individual’s early response, unnecessary side effects and costs of interferon and ribavirin can be spared. As factors other than genotype emerge as predictive of future treatment success, clinicians gain more insight into guiding their patients toward a customized, best possible outcome.
References:
Dalgard, Olav, et al., A Randomized Controlled Trial of Pegylated Interferon Alfa and Ribavirin for 14 vs. 24 Weeks in Patients with HCV Genotype 2 or 3 and Rapid Virological Response, Hepatology, January 2008.
Fried MW, et al., Rapid virological response is a more important predictor of sustained virological response (SVR) than genotype in patients with chronic hepatitis C virus infection, Program and abstracts of the 43rd Annual Meeting of the European Association for the Study of the Liver, Journal of Hepatology, April 2008.
http://clinicaloptions.com, RVR a Better Predictor of SVR Than HCV Genotype in HCV-Infected Patients With Peginterferon alfa-2a Plus Ribavirin, Clinical Care Options LLC, 2008.
Mangia, Alessandra, et al., Individualized Treatment Duration for Hepatitis C Genotype 1 Patients: A Randomized Controlled Trial, Hepatology, January 2008.
www.hcvadvocate.org, Adjustment of Treatment Duration Based on Early Response, Liz Highleyman, HCV Advocate, The Hepatitis C Support Project, March 2008.
www.hivandhepatitis.com, Duration of Pegylated Interferon plus Ribavirin May Be Tailored Based on Early Patient Response, Liz Highleyman, hivandhepatitis.com, 2008.
www.hivandhepatitis.com, HCV Genotype Is the Strongest Predictor of Sustained Virological Response after Retreatment of Hepatitis C Patients: Final Results of EPIC 3, hivandhepatitis.com, 2008.
www.natap.org, Virological response at 4 and 12 weeks predict high rates of sustained virological response in genotype 1 patients treated with peginterferon alfa-2a (40KD) plus ribavirin, Jules Levin, EASL, April 2007.
