Clinical factors leading to a change in management in chronic hepatitis B patients managed in a tertiary setting.

BACKGROUND: Newer antiviral agents for chronic hepatitis B (CHB) are highly effective, with minimal risks of complications and development of resistance. AIM: To identify the proportion of patients with CHB on treatment who will not require alteration of management and the clinical factors of those who will require closer monitoring. METHODS: Patients with CHB who were on entecavir and/or tenofovir between January 2011 and December 2016 were retrospectively studied. According to the initial treatment plan provided by the managing physician, any deviation in the interval of follow up, choice of investigations and alteration of medical therapy were considered a change in CHB management. We also evaluated the predictability of these changes, factors associated with higher frequency of change and the additional cost of managing stable patients with CHB in a tertiary setting. RESULTS: Of the patients, 75.7% (n = 87/115) did not have a change in CHB management; 85.6% of the changes in management were predictable based on liver function tests, hepatitis B virus DNA polymerase chain reaction levels and liver ultrasound. Interpreter use (OR (95% CI) = 2.41 (1.01-5.76)), liver cirrhosis (OR (95% CI) = 4.11 (1.44-11.75)) and immunosuppression (OR (95% CI) = 3.81 (1.2-12.06)) were associated risk factors. Overall, there was an incremental annual cost of AU$60 166 to manage patients who did not require alteration of their CHB management in our institution. CONCLUSION: The majority of stable CHB patients on highly potent antiviral treatment do not require alteration of management. While additional investigations are required, this study highlights the potential for a shared primary care approach in highly selected CHB patients.

Generation of a chimeric hepatitis C replicon encoding a genotype-6a NS3 protease and assessment of boceprevir (SCH503034) sensitivity and drug-associated mutations.

BACKGROUND: Genotype (gt)6 HCV is common amongst HCV-positive populations of the Asia-Pacific region but cell culture models for this gt have only recently been developed. Boceprevir (SCH503034) is a clinically available inhibitor of the HCV NS3 protein. We investigated the efficacy of boceprevir for inhibiting replication of a chimeric gt1b replicon encoding a gt6a NS3 protease and defined the development of mutations in the protease when boceprevir treatment was applied. METHODS: We constructed a chimeric gt1b subgenomic replicon encoding a gt6 NS3 protease (NS3p) sequence (gt6NS3p_gt1b). The boceprevir EC50 value against replication of this replicon was determined using quantitative reverse transcriptase PCR. Next-generation sequencing was used to identify nucleotide changes associated with boceprevir resistance. The replication capacities of chimeric replicons containing mutations associated with boceprevir resistance were determined by colony formation efficiency assays. RESULTS: The boceprevir EC50 value for the gt6NS3p_gt1b replicon was 535 ±79 nM. Boceprevir-resistant gt6NS3p_gt1b replicon cell lines could be selected and they demonstrated drug-associated amino acid changes that have previously been reported in other HCV gts. Interestingly, no mutations were observed at A156, a position defined for boceprevir resistance in gt1 NS3p, while mutation at N122, which is rarely reported in boceprevir-resistant gt1 proteases, was frequently observed. Re-introduction of these mutations into the chimeric replicon altered their replication capacity, ranging from complete abolishment of replication (A156T) to increasing replication capacity (V36A, N122S). This report provides the first characterization of gt6 HCV resistance to boceprevir. CONCLUSIONS: A chimeric HCV replicon encoding gt6 NS3 protease is sensitive to boceprevir and develops drug-resistant mutations at amino acid sites previously reported for other gts. Mutation at N122 also appears to be associated with boceprevir resistance in the gt6 NS3 protease.