Article first published online: 10 JAN 2012
DOI: 10.1111/j.1365-2893.2011.01520.x
© 2012 Blackwell Publishing Ltd
Special Issue: How to Optimize Treatment of Hepatitis C
Special Issue: How to Optimize Treatment of Hepatitis C
Chronic carriers of the hepatitis C virus (HCV) constitute a huge reservoir of cirrhosis and hepatocellular carcinoma which, ultimately, are a growing cause of liver-related mortality worldwide [1]. Treatment with pegylated interferon (PegIFN) combined with ribavirin (Rbv) is the only option for preventing HCV-related end stage liver disease.
Currently, sustained virological response (SVR) rates, the surrogate definition of a cure of the disease, of up to 90% are achievable in patients infected with HCV genotypes 2 and 3, but the SVR rate is about 50% for patients infected with HCV genotype 1, the most common form [2]. Therefore, patients infected with HCV genotypes 1 and 4 who fail to respond to IFN-based therapies represent a very important unmet clinical need in the HCV arena, as highlighted also by the unsatisfactory success rate of re-treatment with Peg IFN/Rbv [3,4]. Therefore, it was with understandably great anticipation that hepatologists awaited the final reports on triple therapy with the orally bio-available protease inhibitors (PI) telaprevir and boceprevir, known to improve SVR rates to 75% in this difficult-to-cure population [5,6]. Even more welcomed were the final reports of the Prove 3 (telaprevir) and Respond 2 (boceprevir) studies, which demonstrated that re-treatment of relapsing or nonresponding HCV genotype 1 infections with standard therapy plus a PI significantly increases the likelihood of HCV eradication [7,8].
Now that we have confirmation that the new direct-acting antiviral agents will provide a major breakthrough in the treatment of patients with HCV genotype 1 infections, although at the cost of increased treatment-related side effects and discontinuation rates, we must adopt new therapeutic algorithms based on careful pretreatment patient stratification.
This purpose might be served by the recent description of a set of polymorphisms in the interleukin 28B (IL28B) gene region, which encodes interferon λ3 and is associated with response to Peg IFN/Rbv therapy in HCV patients [9,10]. In fact, the link between IL28B genotype and treatment outcome might allow for pretreatment stratification aimed at refining not only decisions regarding the initiation of current therapy, but also the design of clinical trials with new direct antiviral agents. Indeed, it is worthwhile to test both a strategy restricting dual therapy to patients with the favourable IL28B genotype (CC), while administering triple therapy to those with unfavourable genotypes (TT or CT), and also a strategy in which patients are stratified by IL28B genotype for dosing and duration of antiviral therapy. This strategy might be even more cost-effective once ‘second wave’ direct antiviral agents, endowed with higher genetic barriers and broader antiviral activity against different HCV genotypes, become available.
Indeed, we should acknowledge that the applicability of first generation antivirals is jeopardized by a very high risk of generating resistant HCV mutants with variable degrees of replicative fitness and by low tolerability, which could translate into higher rates of treatment discontinuation compared to dual therapy with PegIFN/Rbv alone [11].
Cutaneous rash, pruritus and anaemia following telaprevir versus anaemia and disgeusia following boceprevir were more common in the triple regimen than in the standard of care groups. Undoubtedly, the management and treatment of patients with chronic HCV infection will become more complicated, requiring increased scientific and clinical expertise to meet the new challenges that this first generation of direct-acting antivirals will provide. Although the development of viral resistance to PIs occurs in a minority of patients receiving the triple therapy regimens, it is important to outline that those mutant strains will likely preclude or delay our patients from receiving other class-specific direct antiviral agents [12].
Related:Dermatological side effects of hepatitis C and its treatment: Patient management in the era of direct-acting antivirals
Boceprevir and telaprevir for hepatitis C: safety management in clinical practice
Because alternative anti-HCV agents such as nucleoside or nonnucleoside NS5B polymerase inhibitors are in the early stages of development, patients with resistant disease will be left waiting for future drugs to enter the market before an effective anti-HCV regimen can be started. Thus, when a patient is considered for treatment with PIs, a careful risk/benefit evaluation must be conducted at the individual level; careful patient selection for triple therapy is mandatory. This is even more important when re-treating patients with genotype-1 infections, where breakthrough rates are higher among nonresponders (particularly those with < 1 log decline of HCV-RNA at week 4 of treatment) than among relapsers and among patients infected with subtype 1a compared with subtype 1b.
The clinical implication of these observations is clear: PIs require some degree of viral response to PegIFN and Rbv to maximize their antiviral activity, therefore suggesting that treatment be prioritized in relapsing patients and in those primary nonresponders experiencing a ≥1 log decline in HCV-RNA at week 4 of lead in treatment with PegIFN+Rbv. In addition, an updating of HCV genotype definition is mandatory to avoid false positive diagnosis of 1b using tests based on sequence analysis or reverse hybridization of only the 5′ noncoding region of HCV, a risk that can be avoided using a second generation reverse hybridization assay that targets both the 5′ noncoding and the core-coding region of HCV [13]. Last but not least, the landscape of therapeutic effectiveness needs to be reshaped in terms of reducing HCV-related mortality at the population level.
Given that HCV-related mortality in the general population can only be reduced by increasing the number of HCV patients on treatment (only 1% in Italy) and that most of the infected patients are unaware of their liver disease because of its symptomless course, more effort should be made to identify infected patients to be treated.
Although the implementation of screening of persons at risk for HCV is an important step in this direction, we must realize that in many European countries including Italy, more than half of the patients with chronic hepatitis C lack a history of exposure to known risk factors and, therefore, will escape identification based on such a case-finding strategy [14]. As it is estimated that the health burden of HCV-related complications will continue to grow in most countries, in May 2010 the World Health Organization declared hepatitis a global and urgent health issue to be combated through prevention campaigns and widespread treatment of patients with the aim of avoiding progression to cirrhosis in individuals already infected.
To offer anti-HCV therapy to every eligible patient, efforts should be geared toward improving the currently available screening programs for HCV infection, such as in individuals born between 1950 and 1960, as was recently suggested by the American Association for the Study of the Liver. A Markov model analysis clearly shows that increasing the number of patients currently treated with dual therapy by 50% would prevent 30% of liver-related deaths because of HCV by 2030 [15]. The advent of a rapid point-of-care test for HCV exposure that can be performed without phlebotomy needs to be recognized as a major breakthrough in this field [16]. Obviously, an agreement between local health authorities and big pharma to significantly decrease drug costs is necessary to make an expanded HCV therapy program affordable.
Declaration of personal interests:
Massimo Colombo received grants and research support from Merck, Roche, BMS, Gilead Science and participated in Advisory Committees organized by Merck, Roche, Novartis, Bayer, BMS, Gilead Science, Tibotec, Vertex and moreover acted as a speaker and as a teacher for Tibotec, Roche, Novartis, Bayer, BMS, Gilead Science, Vertex.
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