Modelling hepatitis C virus infection and the development of hepatocellular carcinoma

Another Step Toward Hepatitis C Elimination: An Economic Evaluation of an Irish National Birth Cohort Testing Program

OBJECTIVES

We aimed to evaluate the cost-effectiveness of offering once-off birth cohort testing for hepatitis C virus (HCV) to people in Ireland born between 1965 and 1985, the cohort with the highest reported prevalence of undiagnosed chronic HCV infection.

METHODS

Systematic and opportunistic HCV birth cohort testing programs, implemented over a 4-year timeframe, were compared with the current practice of population risk-based testing only in a closed-cohort decision tree and Markov model hybrid over a lifetime time horizon. Outcomes were expressed in quality-adjusted life-years (QALYs). Costs were presented from the health system's perspective in 2020 euro (€). Uncertainty was assessed via deterministic, probabilistic, scenario, and threshold analyses.

RESULTS

In the base case, systematic testing yielded the largest cost and health benefits, followed by opportunistic testing and risk-based testing. Compared with risk-based testing, the incremental cost-effectiveness ratio for opportunistic testing was €14 586 (95% confidence interval €4185-€33 527) per QALY gained. Compared with opportunistic testing, the incremental cost-effectiveness ratio for systematic testing was €16 827 (95% confidence interval €5106-€38 843) per QALY gained. These findings were robust across a range of sensitivity analyses.

CONCLUSIONS

Both systematic and opportunistic birth cohort testing would be considered an efficient use of resources, but systematic testing was the optimal strategy at willingness-to-pay threshold values typically used in Ireland. Although cost-effective, any decision to introduce birth cohort testing for HCV (in Ireland or elsewhere) must be balanced with considerations regarding the feasibility and budget impact of implementing a national testing program given high initial costs and resource use.

Advanced Hepatitis C Virus Replication PDE Models within a Realistic Intracellular Geometric Environment

The hepatitis C virus (HCV) RNA replication cycle is a dynamic intracellular process occurring in three-dimensional space (3D), which is difficult both to capture experimentally and to visualize conceptually. HCV-generated replication factories are housed within virus-induced intracellular structures termed membranous webs (MW), which are derived from the Endoplasmatic Reticulum (ER). Recently, we published 3D spatiotemporal resolved diffusion⁻reaction models of the HCV RNA replication cycle by means of surface partial differential equation (sPDE) descriptions. We distinguished between the basic components of the HCV RNA replication cycle, namely HCV RNA, non-structural viral proteins (NSPs), and a host factor. In particular, we evaluated the sPDE models upon realistic reconstructed intracellular compartments (ER/MW). In this paper, we propose a significant extension of the model based upon two additional parameters: different aggregate states of HCV RNA and NSPs, and population dynamics inspired diffusion and reaction coefficients instead of multilinear ones. The combination of both aspects enables realistic modeling of viral replication at all scales. Specifically, we describe a replication complex state consisting of HCV RNA together with a defined amount of NSPs. As a result of the combination of spatial resolution and different aggregate states, the new model mimics a cis requirement for HCV RNA replication. We used heuristic parameters for our simulations, which were run only on a subsection of the ER. Nevertheless, this was sufficient to allow the fitting of core aspects of virus reproduction, at least qualitatively. Our findings should help stimulate new model approaches and experimental directions for virology.

The Indian National Association for Study of the Liver (INASL) Consensus on Prevention, Diagnosis and Management of Hepatocellular Carcinoma in India: The Puri Recommendations

Hepatocellular carcinoma (HCC) is one of the major causes of morbidity, mortality and healthcare expenditure in patients with chronic liver disease. There are no consensus guidelines on diagnosis and management of HCC in India. The Indian National Association for Study of the Liver (INASL) set up a Task-Force on HCC in 2011, with a mandate to develop consensus guidelines for diagnosis and management of HCC, relevant to disease patterns and clinical practices in India. The Task-Force first identified various contentious issues on various aspects of HCC and these issues were allotted to individual members of the Task-Force who reviewed them in detail. The Task-Force used the Oxford Center for Evidence Based Medicine-Levels of Evidence of 2009 for developing an evidence-based approach. A 2-day round table discussion was held on 9th and 10th February, 2013 at Puri, Odisha, to discuss, debate, and finalize the consensus statements. The members of the Task-Force reviewed and discussed the existing literature at this meeting and formulated the INASL consensus statements for each of the issues. We present here the INASL consensus guidelines (The Puri Recommendations) on prevention, diagnosis and management of HCC in India.

Liver transplantation for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary tumor of the liver and is considered an aggressive tumor with mean survival estimated between 6 and 20 months. Hepatitis B and C are the most common etiologies. Pathological, laboratory and radiologic imaging all aid in diagnosis but much controversy exists in the utilization of any given modality. Many treatment options exist for management of HCC, each has its own limitation. Liver transplantation offers the most reasonable expectation for curative treatment while simultaneously removing the burden of the diseased liver. Still, advancements in the field have thus far not yet matched its potential, although new immunosuppressive and chemotherapy regimen may allow transplantation to push the envelope once again.

How virus persistence can initiate the tumorigenesis process

Human oncogenic viruses are defined as necessary but not sufficient to initiate cancer. Experimental evidence suggests that the oncogenic potential of a virus is effective in cells that have already accumulated a number of genetic mutations leading to cell cycle deregulation. Current models for viral driven oncogenesis cannot explain why tumor development in carriers of tumorigenic viruses is a very rare event, occurring decades after virus infection. Considering that viruses are mutagenic agents per se and human oncogenic viruses additionally establish latent and persistent infections, we attempt here to provide a general mechanism of tumor initiation both for RNA and DNA viruses, suggesting viruses could be both necessary and sufficient in triggering human tumorigenesis initiation. Upon reviewing emerging evidence on the ability of viruses to induce DNA damage while subverting the DNA damage response and inducing epigenetic disturbance in the infected cell, we hypothesize a general, albeit inefficient hit and rest mechanism by which viruses may produce a limited reservoir of cells harboring permanent damage that would be initiated when the virus first hits the cell, before latency is established. Cells surviving virus generated damage would consequently become more sensitive to further damage mediated by the otherwise insufficient transforming activity of virus products expressed in latency, or upon episodic reactivations (viral persistence). Cells with a combination of genetic and epigenetic damage leading to a cancerous phenotype would emerge very rarely, as the probability of such an occurrence would be dependent on severity and frequency of consecutive hit and rest cycles due to viral reinfections and reactivations.