Cost-Effectiveness Analysis of Alternative Antiviral Strategies for the Treatment of HBeAg-Positive and HBeAg-Negative Chronic Hepatitis B in the United Kingdom.

BACKGROUND: Seven drugs are licensed for the treatment of chronic hepatitis B (CHB) in the United Kingdom. Which initial treatment, secondary therapy, and whether antivirals should be given alone or in combination are questions of considerable uncertainty. OBJECTIVE: The aim of this model was to undertake a comprehensive economic evaluation of all antiviral treatments for CHB to recommend the most cost-effective therapeutic sequence. METHODS: We developed a probabilistic Markov model to compare the cost-effectiveness of all clinically relevant antiviral treatment sequences for nucleos(t)ide-naive adults with hepatitis B e-antigen (HBeAg)-positive or HBeAg-negative CHB. Relative rates of HBeAg seroconversion and viral suppression were obtained from a network meta-analysis. Data on mortality, antiviral drug resistance, durability of response, adverse events, and costs were obtained from published literature. Results are reported in terms of lifetime costs, quality-adjusted life-years (QALYs), and expected net benefit. RESULTS: In the base-case analysis, pegylated interferon alpha-2a (peg-IFN α-2a) followed by tenofovir disoproxil fumarate was most effective and cost-effective in HBeAg-positive patients, with a cost of £7488 per QALY gained compared with no treatment. In HBeAg-negative patients, peg-IFN α-2a followed by entecavir was most effective and cost-effective, with a cost of £6981 per QALY gained. The model was robust to a wide range of sensitivity analyses. CONCLUSIONS: Peg-IFN α-2a followed by tenofovir disoproxil fumarate or entecavir is the most effective antiviral treatment strategy for people with both variants of CHB. At a cost of less than £10,000 per QALY gained, these sequences are considered cost-effective in England and Wales. The results of this analysis were used to inform 2013 National Institute for Health and Care Excellence guideline recommendations.

Key mutations in the C-terminus of the HBV surface glycoprotein correlate with lower HBsAg levels in vivo, hinder HBsAg secretion in vitro and reduce HBsAg structural stability in the setting of HBeAg-negative chronic HBV genotype-D infection.

Increasing evidences suggest that HBsAg-production varies across HBV-genotypes. HBsAg C-terminus plays a crucial role for HBsAg-secretion. Here, we evaluate HBsAg-levels in different HBV-genotypes in HBeAg-negative chronic infection, the correlation of specific mutations in HBsAg C-terminus with HBsAg-levels in-vivo, their impact on HBsAg-secretion in-vitro and on structural stability in-silico.HBsAg-levels were investigated in 323 drug-naïve HBeAg-negative patients chronically infected with HBV genotype-D(N = 228), -A(N = 65) and -E(N = 30). Genotype-D was characterized by HBsAg-levels lower than genotype-A and -E (3.3[2.7-3.8]IU/ml; 3.8[3.5-4.2]IU/ml and 3.9[3.7-4.2]IU/ml, P < 0.001). Results confirmed by multivariable analysis correcting for patients'demographics, HBV-DNA, ALT and infection-status.In genotype-D, specific C-terminus mutations (V190A-S204N-Y206C-Y206F-S210N) significantly correlate with HBsAg<1000IU/ml(P-value from <0.001 to 0.04). These mutations lie in divergent pathways involving other HBsAg C-terminus mutations: V190A + F220L (Phi = 0.41, P = 0.003), S204N + L205P (Phi = 0.36, P = 0.005), Y206F + S210R (Phi = 0.47, P < 0.001) and S210N + F220L (Phi = 0.40, P = 0.006). Notably, patients with these mutational pairs present HBsAg-levels 1log lower than patients without them(P-value from 0.003 to 0.02). In-vitro, the above-mentioned mutational pairs determined a significant decrease in HBsAg secretion-efficiency compared to wt(P-value from <0.001 to 0.02). Structurally, these mutational pairs reduced HBsAg C-terminus stability and determined a rearrangement of this domain.In conclusion, HBsAg-levels in genotype-D are significantly lower than in genotype-A and -E in HBeAg-negative patients. In genotype-D, specific mutational clusters in HBsAg C-terminus correlate with lower HBsAg-levels in-vivo, hamper HBsAg-release in-vitro and affect its structural stability, supporting their detrimental role on HBsAg-secretion. In this light, genotypic-testing can be a valuable tool to optimize the clinical interpretation of HBsAg in genotype-D and to provide information on HBV-pathogenicity and disease-progression.