Clinical impact of treatment timing for chronic hepatitis C infection: a decision model.

Recent advances in the treatment of hepatitis C virus (HCV) infection have led to the availability of both highly efficacious interferon-containing and interferon-sparing regimens. However, the use of such therapies faces restrictions due to high costs. For patients who are medically eligible to receive interferon, the choice between the two will likely be impacted by preferences surrounding interferon, severity of disease, coverage policies and out-of-pocket costs. We developed a decision model to quantify the trade-offs between immediate, interferon-containing therapy and delayed, interferon-free therapy for patients with chronic, genotype 1 HCV infection. We projected the quality-adjusted life expectancy stratified by the presence or absence of cirrhosis for four strategies: (i) no treatment; (ii) immediate, one-time treatment with an interferon-containing regimen; (iii) immediate treatment as above with the opportunity for retreatment in patients who fail to achieve sustained virologic response with interferon-free therapy in 1 year; and (iv) delayed therapy with interferon-free therapy in 1 year. When compared to one-time immediate treatment with the interferon-containing regimen, delayed treatment with the interferon-free regimen in 1 year resulted in longer life expectancy, with a 0.2 quality-adjusted life year (QALY) increase in noncirrhotic patients, and a 1.1 QALY increase in patients with cirrhosis. This superiority in health benefits was lost when wait time for interferon-free therapy was greater than 3-3.2 years. In this modelling analysis, interferon-free therapy resulted in superior health benefits compared to immediate therapy with interferon until wait time exceeded 3-3.2 years. Such data can inform decision-making regarding treatment initiation for HCV as healthcare financing evolves.

JC virus enters human glial cells by clathrin-dependent receptor-mediated endocytosis.

The human polyomavirus JC virus (JCV) is the etiologic agent of a fatal central nervous system (CNS) demyelinating disease known as progressive multifocal leukoencephalopathy (PML). PML occurs predominantly in immunosuppressed patients and has increased dramatically as a result of the AIDS pandemic. The major target cell of JCV infection and lytic replication in the CNS is the oligodendrocyte. The mechanisms by which JCV initiates and establishes infection of these glial cells are not understood. The initial interaction between JCV and glial cells involves virus binding to N-linked glycoproteins containing terminal alpha(2-6)-linked sialic acids. The subsequent steps of entry and targeting of the viral genome to the nucleus have not been described. In this report, we compare the kinetics and mechanisms of infectious entry of JCV into human glial cells with that of the related polyomavirus, simian virus 40 (SV40). We demonstrate that JCV, unlike SV40, enters glial cells by receptor-mediated clathrin-dependent endocytosis.