Efficacy of lamivudine therapy in elderly patients with chronic hepatitis B infection

Hepatitis B and elders: An underestimated issue

As the world's population becomes older, the burden of hepatitis B virus in elderly has to be considered. The liver changes with aging and its function is eventually altered. The prevalence of hepatitis B virus is paradoxically more important in elderly in areas having vaccination programs, because of a loosening of the prevention in older patients. Some differences in hepatitis B presentation must be enhanced in elderly: lower spontaneous hepatitis B surface antigen clearance after a recent contamination, major risk of cirrhosis and hepatocarcinoma. Acute hepatitis B seems to be more often symptomatic, with a great risk of chronicity. Hepatocarcinoma linked to hepatitis B virus has a higher prevalence and a different presentation in elderly. Its treatment is the same as in younger people but is less often possible. Liver transplantation is contraindicated after 70 years old. Hepatitis B treatment panel is the same as in younger people (pegylated interferon, nucleoside or nucleotide agents). It gives identical results with no particular adverse events if the precautions for use are followed. Vaccination is less efficient, as in immunocompromised patients, and needs specific protocols.

Partial virological response to three different nucleotide analogues in naive patients with chronic hepatitis B

BACKGROUND

The definition of partial virological response (PVR) was proposed because of its clinical relevance. PVR relates to subsequent therapeutic failure which results in the modification of the regimen. Whether this rationale can be applied to all nucleotide analogues (NA) is not clear. This study was undertaken to analyze PVR influence on therapeutic outcomes during lamivudine, entecavir or tenofovir monotherapy in NA-naive patients with chronic hepatitis B in routine clinical practice.

METHODS

We retrospectively analyzed 150 NA-naive patients with chronic hepatitis B. These subjects received lamivudine, entecavir or tenofovir monotherapy between February 2001 and July 2013.

RESULTS

Sixty-nine patients were treated with lamivudine, 35 with entecavir, and 46 with tenofovir. The median therapeutic duration was 19.5 (6-147) months. PVR rates at 24 weeks were similar among three NAs (lamivudine 33.3%, entecavir 35.0%, tenofovir 32.4%, P=0.981). For all three NAs, patients with a higher baseline viral load or HBeAg-positive status had a higher serum viral positive rate tested by polymerase chain reaction at week 24 and 48. Cumulative probability of virological breakthrough (VBR) for patients treated with lamivudine was 67% at 5 years, and PVR at 24 weeks was the independent risk factor for VBR (HR: 3.09; 95% CI: 1.09-8.74; P=0.034); also lamivudine treated patients older than 50 years seemed to have a tendency for VBR (HR: 2.80; 95% CI: 0.99-8.18; P=0.052). A majority of entecavir and tenofovir partial responders achieved and maintained virological response with prolonged monotherapy, except one entecavir treated patient who experienced VBR due to resistance mutations.

CONCLUSIONS

Management strategy for lamivudine treatment should include adaptation of regimen according to PVR as an on-treatment response parameter due to its relation with unacceptably high VBR probability. Similar conclusion should not be directly related to entecavir or tenofovir treatment.

Liver physiology and liver diseases in the elderly

The liver experiences various changes with aging that could affect clinical characteristics and outcomes in patients with liver diseases. Both liver volume and blood flow decrease significantly with age. These changes and decreased cytochrome P450 activity can affect drug metabolism, increasing susceptibility to drug-induced liver injury. Immune responses against pathogens or neoplastic cells are lower in the elderly, although these individuals may be predisposed to autoimmunity through impairment of dendritic cell maturation and reduction of regulatory T cells. These changes in immune functions could alter the pathogenesis of viral hepatitis and autoimmune liver diseases, as well as the development of hepatocellular carcinoma. Moreover, elderly patients have significantly decreased reserve functions of various organs, reducing their tolerability to treatments for liver diseases. Collectively, aged patients show various changes of the liver and other organs that could affect the clinical characteristics and management of liver diseases in these patients.

Viral hepatitis in the elderly

As life expectancy continues to rise, elderly adults represent a rapidly growing proportion of the population. The likelihood of complications of acute and chronic liver disease and overall mortality are higher in elderly populations. Several physiological changes associated with aging, greater prevalence of co-morbid conditions, and cumulative exposure to hepatotropic viruses and environmental hepatotoxins may contribute to worse outcomes of viral hepatitis in the elderly. Although pharmacotherapy for hepatitis B and C continues to evolve, the efficacy, tolerability, and side effects of these agents have not been studied extensively in elderly adults. Immunization against hepatitis A and B in naïve elderly adults is an important public health intervention that needs to be revised and broadened.

Liver disease, HIV and aging

The life expectancy of HIV-infected patients has increased due to the efficacy of highly active antiretroviral therapy (HAART) in controlling HIV replication; thus, the population living with HIV infection is steadily aging. Liver-related morbidity and mortality has emerged as a leading problem in HIV-infected patients. Since aging, HIV infection and HAART all affect the liver, understanding the impact of the combination of these factors on liver disease is crucial for optimisation of care in the aging HIV-infected population. This review will focus on the current understanding of liver disease in older (>50 years old) HIV-negative individuals and in HIV-infected individuals. Areas for future research in the area of HIV, liver disease and aging will also be discussed.

The therapeutic response of antiviral therapy in HBsAg-positive renal transplant recipients and a long-term follow-up

BACKGROUND

Early prediction of lamivudine (LAM) response by individualized monitoring of serum HBV DNA like roadmap concept, and investigation of the outcome after LAM discontinuation in renal transplant recipients (RTRs) with chronic hepatitis B (CHB).

METHODS

We conducted a study on 19 RTRs with HBV infection receiving LAM treatment for 2 years from 2004 to 2007. HBV DNA level was assessed at baseline, 12, 24, 52, and 104 weeks after treatment. Risk factors of tyrosine-methionine-aspartate-aspartate (YMDD) mutation on treatment and relapse rate of HBV after LAM discontinuation were analyzed.

RESULTS

HBV DNA levels became undetectable in 32, 37, 63, and 53% of patients after 12, 24, 52, and 104 weeks of LAM treatment, respectively. Overall, three (16%) and five (33%) patients were detected with YMDD mutations at week 52 and 104, respectively. In the concept of roadmap, of the seven patients with inadequate virologic response (IAVR) at week 24, five had YMDD mutations. There was no significant association of YMDD mutations with age, gender, genotype, cirrhosis, HBeAg status, baseline HBV DNA, precore/core promoter mutations, and primary response, except IAVR at week 24 (P = 0.001). The relapse rate of HBV after LAM discontinuation was high (75%) during a median follow-up of 65 weeks.

CONCLUSIONS

The rate of LAM resistance in RTRs is similar to immunocompetent CHB patients in a 2-year therapy. By roadmap concept, RTRs with IAVR require a change in therapy to prevent viral resistance. Relapse after LAM withdrawal is frequent. Long-term antiviral therapy is crucial for immunosuppressed patients.

Chronic liver disease in an ageing population

The prevalence of chronic liver disease is increasing in the elderly population. With a mostly asymptomatic or non-specific presentation, these diseases may easily go undiagnosed. Abnormal liver function tests of unknown cause are a common reason for referral to secondary care. Investigating the older person with abnormal liver function is important; even with mild abnormalities, the same vigilance should be applied to an older person as in a young person. Liver biopsy is safe but often overlooked in this age group and may provide useful information to diagnose, direct therapy and prognosticate. Treatment options are similar for all age groups, with a few subtle differences, although further evidence is frequently required for the older population. Morbidity and age-adjusted mortality are often more severe in older people, and therefore early diagnosis and intervention is important. Presented here are the most common chronic liver diseases that geriatricians are likely to encounter in clinical practise. Their epidemiology, clinical features, investigation, treatment and mortality are described with a particular focus on the elderly population.

Effect of β-L-D4A on human DNA polymerases β and δ and its mechanism

AIM: To purify and characterize the DNA polymerase δ and investigate the side effects of β-L-D4A (a novel nucleoside analog) on human DNA polymerases β and δ.

METHODS: Human DNA polymerase δ was separated from crude extract of human Hela cells by ion exchange chromatography. Detailed kinetic parameters were determined for β-L-D4A against DNA polymerases β and δ.

RESULTS: Human DNA polymerase δ was purified and characterized with a yield of 15% and a specific activity of 1911 Ukat/mg. When β-L-D4A was used as an inhibitor, the kinetic parameters of human DNA polymerases β and δ were Km = 1.86 μmol/L and 2.45 μmol/L, IC₅₀ = 25.21 μmol/L and 150.1 μmol/L, Ki = 24.03 μmol/L and 132.7 μmol/L, respectively, suggesting that the inhibitory effect of β-L-D4A on human DNA polymerases β and δ was less than that of lamivudine.

CONCLUSION: β-L-D4A is a competitive inhibitor of DNA polymerases β and δ. Its toxic side effects on DNA polymerases β and δ are less than lamivudine. It can be expected to become a high efficient and low toxic anti-HBV agent.

Effect and mechanism of β-L-D4A on DNA polymerase α

AIM: To investigate the safety of β-L-D4A on DNA polymerase α.

METHODS: Ion exchange chromatography was used to separate DNA polymerase α from crude extract of human Hela cells. Detailed kinetic parameters were determined for β-L-D4A against DNA polymerase α.

RESULTS: DNA polymerase α was purified with 4% yield and 31 000 units/mg specific activity. The Michaelis constant (Km = 3.22 μmol/L), 50% inhibition concentration (IC50 = 178.49 μmol/L) and inhibition constant (Ki = 126 μmol/L) of β-L-D4A were determined by kinetic analysis.

CONCLUSION: β-L-D4A is a more safe nucleoside for hepatitis B virus (HBV) infection with a lower host toxicity.