The Nobel Prize in Medicine 2020 for the Discovery of Hepatitis C Virus: Transforming Hepatology

Road to elimination of HCV: Clinical challenges in HCV management

Since its discovery in 1989, the road to a cure for hepatitis C virus (HCV) has been slow, but most patients can now expect to achieve a sustained virological response (SVR). With direct-acting antiviral (DAA) combination therapies such as glecaprevir/pibrentasvir and velpatasvir/sofosbuvir, 98% of patients successfully eradicate the virus, even if previous treatments failed or if resistance-associated substitutions (RASs) are present. Adverse events are rare or mild, and patients with compensated cirrhosis and other co-morbidities are often eligible for treatment. However, a small number of patients fail to eradicate the virus even after retreatment. The cause of failure is mainly due to emergence of NS5A P32 deletion mutants after initial DAA therapy in genotype 1b patients, although the reason is unknown for some patients. Alternative therapies that do not rely on NS5A inhibitors, such as sofosbuvir plus ribavirin, can be attempted in these patients. While scaled-up treatment efforts present a challenge, another problem is that many carriers are unaware of their infection. Long-term damage to the liver becomes irreversible, and patients who are not diagnosed in time can develop liver cancer or liver failure even after eliminating the virus. The long-term costs of treatment of advanced liver disease in undiagnosed patients relative to the immediate costs of DAA therapy should be considered. As no vaccine is yet available, eventual elimination of the virus requires identifying and treating undiagnosed cases and screening of high-risk populations such as injection drug users and men who have sex with men and female sex workers.

Hepatitis C virus infection and diabetes: A complex bidirectional relationship

Chronic hepatitis C (CHC) and diabetes represent two severe chronic conditions responsible for a considerable number of deaths worldwide. They have a complex, bidirectional relationship. On the one hand, several cohort studies have shown that chronic HCV infection increases both the risk of developing diabetes in non-diabetic subjects (by inducing insulin resistance and promoting β-cell dysfunction) as well as the risk of developing macro and microvascular complications in patients with known diabetes; on the other hand, diabetes is an independent risk factor for liver-related events among patients with CHC, including a higher incidence of hepatocellular carcinoma, liver-related death and transplantation. Importantly, sustained virological response, which can be obtained in the vast majority of patients with the use of direct antiviral agents, does not only lead to a lower rate of liver-related outcomes, but also to improvements of glycemic control and reduction in the rate of complications among patients with diabetes. The aim of this review is to summarize available clinical evidence on the association among CHC, diabetes and related clinical outcomes. We will also briefly discuss the biological mechanisms underpinning the association between CHC and diabetes, as well as the implications this relationship should have on everyday clinical practice.

Liver cancer risk after HCV cure in patients with advanced liver disease without non-characterized nodules

BACKGROUND & AIMS

Recognition of non-characterized liver nodules (NCLN) prior to direct-acting antivirals (DAAs) is associated with increased hepatocellular carcinoma (HCC) risk in patients with HCV. The risk of HCC has not been defined in F3/F4 patients in whom NCLN have been ruled-out before starting DAAs and at sustained virological response (SVR). This study aimed to estimate HCC incidence in this population.

METHODS

We performed a prospective study including HCV-infected patients with F3/F4 fibrosis, without a history of HCC, and who achieved SVR after DAAs. Patients were only included if they had undergone ultrasound imaging that excluded the presence of HCC/NCLN within 30 days after SVR. All patients were evaluated every 6 months until developing primary liver cancer, death or withdrawal of informed consent. HCC incidence was expressed per 100 patient-years (/100PY). Adherence to screening program was calculated every 6 months for the first 48 months.

RESULTS

A total of 185 patients (63/122, F3/F4) were included. Among those with cirrhosis, 92% were Child-Pugh A and 42.7% had clinically significant portal hypertension (CSPH). Albumin-bilirubin score was 1 in 84.9% and 2 in 15.1% of patients, respectively. The median clinical and radiologic follow-up was 52.4 months and 48 months, respectively. Ten patients developed HCC: HCC incidence was 1.46/100PY (95% CI 0.79-2.71) in the whole cohort, 2.24/100PY (95% CI 1.21-4.17) in F4 only and 3.63/100PY (95% CI 1.95-6.74) in patients with CSPH. No HCC was registered in patients with F3. Median time between SVR and HCC occurrence was 28.1 months; 12 non-primary liver cancers were also identified.

CONCLUSIONS

Patients with cirrhosis without NCLN at SVR remain at risk of HCC development. The absence of HCC in patients with F3 reinforces their marginal cancer risk, but prospective studies are needed to exclude them from screening programs.

LAY SUMMARY

Patients with HCV-related cirrhosis, without non-characterized liver nodules at sustained virologic response, remain at risk of hepatocellular carcinoma despite viral cure. However, the cancer risk after successful direct-acting antiviral treatment is marginal in patients with F3 fibrosis without non-characterized liver nodules. If confirmed in larger prospective studies, current screening recommendations may need to be revisited in this group of patients.

Liver Abnormalities after Elimination of HCV Infection: Persistent Epigenetic and Immunological Perturbations Post-Cure

Chronic hepatitis C (CHC) is a major cause of hepatocellular carcinoma (HCC) worldwide. While directly acting antiviral (DAA) drugs are now able to cure virtually all hepatitis C virus (HCV) infections, even in subjects with advanced liver disease, what happens to the liver and progression of the disease after DAA-induced cure of viremia is only beginning to emerge. Several large-scale clinical studies in different patient populations have shown that patients with advanced liver disease maintain a risk for developing HCC even when the original instigator, the virus, is eliminated by DAAs. Here we review emerging studies derived from multiple, complementary experimental systems involving patient liver tissues, human liver cell cultures, human liver slice cultures, and animal models, showing that HCV infection induces epigenetic, signaling, and gene expression changes in the liver associated with altered hepatic innate immunity and liver cancer risk. Of critical importance is the fact that these virus-induced abnormalities persist after DAA cure of HCV. These nascent findings portend the discovery of pathways involved in post-HCV immunopathogenesis, which may be clinically actionable targets for more comprehensive care of DAA-cured individuals.