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P0605
GENOTYPE SPECIFIC VARIATION IN THE BASAL CORE PROMOTER AND PRE CORE REGIONS IMPACTS HBeAg LEVELS DURING IMMUNE CLEARANCE DISEASE
J. Bayliss1, G. Rosenberg1, A. Thompson2, A. Gaggar3, K. Kitrinos3,
M. Subramanian3, P. Marcellin4, E. Gane5, H.L. Chan6, X. Li1,
D. Colledge1, L. Yuen1, M. Littlejohn1, R. Edwards1, K. Jackson1,
S. Bonanzinga1, R. Hammond1, S. Bowden1, S. Locarnini1, P. Revill1.
1Molecular Research and Development, Victorian Infectious Diseases
Reference Laboratory, Melbourne, 2Gastroenterology, St Vincent’s
Hospital, Fitzroy, Australia; 3Gilead Sciences, Foster City, United States;
4Hˆopital Beaujon, University of Paris, Clichy, France; 5New Zealand
Liver Transplant Unit, Auckland City Hospital, Auckland, New Zealand;
6Department of Medicine and Therapeutics, Chinese University of
Hong Kong, Hong Kong, Hong Kong, China
E-mail: [email protected]
Background and Aims: Basal core promoter (BCP) and precore
(PC) mutations first emerge prior to HBeAg seroconversion and
have been associated with lower HBeAg expression, liver fibrosis
and HCC. GS-US-174-0103 is a phase 3 study evaluating tenofovir
in HBeAg-positive chronic hepatitis B (CHB). The aim of the current study was to use next generation sequencing (NGS) to evaluate the prevalence and quantitative frequency of key mutations within the BCP and PC regions and evaluate their impact on baseline virological profiles within the 103 cohort.
Methods: Illumina MiSeq full genome NGS was performed on a
subset of 94 baseline samples from patients enrolled in study
103, using a threshold for detection of 1%. The results of
NGS were analysed against baseline demographic, clinical, and
serological data including HBVDNA, HBsAg, and HBeAg levels. In
the first instance only mutations in the BCP and PC regions were
considered.
Results: Data were available for 94 patients (median: age 32 yrs,
69% male, HBVDNA 8.43 log10 IU/mL, HBeAg 3.30 log10PEIU/mL, HBsAg 4.71 log10 IU/mL, ALT 137.5 IU/mL, METAVIR fibrosis stage 3). BCP and PC variants were detectable in 34% and 15% of patients using population sequencing respectively vs. 43% and 41% using NGS (p < 0.001). Differences were seen in the genotype (Gt) distribution of mutations within the BCP and PC regions (Table 1).
The presence of mutation at A1762 and G1764 was associated with significantly lower HBeAg expression at baseline (p < 0.0001 for both). Presence of the G1896A mutant alone was not associated with HBeAg expression. HBsAg levels (p = 0.002), A1762T (p = 0.002) and T/C1858G (p = 0.02) were independently associated with HBeAg levels at baseline (model p < 0.0001; R2= 0.31). Baseline HBsAg levels were independently associated with HBVDNA (p < 0.0001), genotype (p = 0.005) and A1762T and G1764SA (p < 0.0001 for both) (model p < 0.0001; R2= 0.48).
Table 1. Selected BCP/PC mutations detected by NGS
n BCP PC
A1762T G1764A T/C1858G G1896A
All 94 34 (36%) 34 (36%) 13 (11%) 39 (41%)
Gt A 26 5 (19%) 6 (23%) 2 (8%) 0
Gt B 19 3 (16%) 3 (16%) 0 15 (79%)
Gt C 21 18 (86%) 19 (90%) 8 (38%) 9 (43%)
Gt D 28 8 (29%) 6 (21%) 1 (4%) 15 (54%)
Conclusions: Clinically important HBV variants are frequently
present in treatment naïve patients during the immune clearance
phase of CHB prior to the initiation of therapy, often below the
threshold of detection by population based Sanger sequencing.
These include mutations associated with increased risk of disease
progression. Our data suggest that molecular differences in the
HBV genome, both within and between genotypes may contribute
to variations in disease status among patients and illustrates the
power of NGS for detecting clinically important variants.
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