Current approaches for treating chronic hepatitis B: when to start, what to start with, and when to stop.
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ABSTRACT:
SUBMITTER: Chang TT
PROVIDER: S-EPMC2716841 | biostudies-other | 2008 May
REPOSITORIES: biostudies-other
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Project description:The constitutively active tyrosine-kinase BCR/ABL1 oncogene plays a key role in human chronic myeloid leukemia development and disease maintenance, and determines most of the features of this leukemia. For this reason, tyrosine-kinase inhibitors are the first-line treatment, offering most patients a life expectancy like that of an equivalent healthy person. However, since the oncogene stays intact, lifelong oral medication is essential, even though this triggers adverse effects in many patients. Furthermore, leukemic stem cells remain quiescent and resistance is observed in approximately 25% of patients. Thus, new therapeutic alternatives are still needed. In this scenario, the interruption/deletion of the oncogenic sequence might be an effective therapeutic option. The emergence of CRISPR (clustered regularly interspaced short palindromic repeats) technology can offer a definitive treatment based on its capacity to induce a specific DNA double strand break. Besides, it has the advantage of providing complete and permanent oncogene knockout, while tyrosine kinase inhibitors (TKIs) only ensure that BCR-ABL1 oncoprotein is inactivated during treatment. CRISPR/Cas9 cuts DNA in a sequence-specific manner making it possible to turn oncogenes off in a way that was not previously feasible in humans. This review describes chronic myeloid leukemia (CML) disease and the main advances in the genome-editing field by which it may be treated in the future.
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Project description:Chronic hepatitis B constitutes a significant health and economic burden to Asian countries. Six medications are now approved for the treatment of chronic hepatitis B, but there is still significant uncertainty with regards to treatment outcomes, cost impact, and benefits in view of the absence of long-term outcomes data. Cost-effectiveness Markov modeling thus allows us to project and estimate long-term outcomes based on current data and compare the cost-benefit between different treatment options. However, there are limitations to these reported studies. Cost-utility indices such as cost/quality-adjusted life years (cost/QALY) may not be intuitive to clinicians and patients. These studies are also usually based on first-world economies, using a benchmark of US$50,000/QALY, and cannot be extrapolated directly to Asia-Pacific countries. Cost-effectiveness of various treatment strategies using a combination of cost-effectiveness indices may provide a more complete picture. These include cost/HBeAg seroconversion for HBeAg-positive patients (range: US$19,400-30,800) and cost/HBV DNA negative (PCR assay) for HBeAg-negative patients (range: US$14,400-32,000) over 5-year time horizon; cost per cirrhosis prevented (range: US$326,000-686,000) and cost per HCC prevented (range: US$654,000-1,380,000) over 10-year horizon using data from REVEAL study, cost per end point complication prevented in cirrhotics (US$9,630/year), and cost per HCC prevented in cirrhotics (US$ 27,600/year) over a 32-month horizon, using data from Asia Lamivudine Cirrhosis Study. More potent antivirals with low resistance appear to have lower cost/clinical end point averted. Published reports of cost-utility analysis comparing treatment using conventional cost/QALY show that all treatment modalities fall below the first-world benchmark of US$50,000/QALY but vary in modeling assumptions and in quality, making comparisons difficult. Reimbursement policies affect out-of-pocket expenses to the patient, and increases the proportion of patients who can afford therapy, but generally do not affect cost-effectiveness. In conclusion, cost-effectiveness analysis is an important tool for health care administrators, clinicians, and patients to decide on the optimal therapy for chronic hepatitis B, but the methodology permits considerable leeway for interpretation of results, thus a combination of cost-effective indices may be needed to paint a more complete picture.
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Project description:Hepatitis B virus (HBV) is a member of Hepadnavirus family, which leads to chronic infection in around 5% of patients with a high risk of developing liver cirrhosis, liver failure, and hepatocellular carcinoma. 1 Despite the availability of prophylactic vaccines against hepatitis B for over 3 decades, there are still more than 2 billion people have been infected and 240 million of them were chronic. Antiviral therapies currently used in the treatment of CHB (chronic hepatitis B) infection include peg-interferon, standard ?-interferon and nucleos/tide analogs (NAs), but none of them can provide sustained control of viral replication. As an alternative strategy, therapeutic vaccines for CHB patients have been widely studied and showed some promising efficacies in dozens of preclinical and clinical trials. In this article, we review current research progress in several types of therapeutic vaccines for CHB treatment, including protein-based vaccines, DNA-based vaccines, live vector-based vaccines, peptide-based vaccines and cell-based therapies. These researches may provide some clues for developing new treatments in CHB infection.
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Project description:The currently recommended treatment for chronic hepatitis B virus (HBV) infection achieves only viral suppression whilst on therapy, but rarely hepatitis B surface antigen (HBsAg) loss. The ultimate therapeutic endpoint is the combination of HBsAg loss, inhibition of new hepatocyte infection, elimination of the covalently closed circular DNA (cccDNA) pool, and restoration of immune function in order to achieve virus control. This review concentrates on new antiviral drugs that target different stages of the HBV life cycle (direct acting antivirals) and others that enhance both innate and adaptive immunity against HBV (immunotherapy). Drugs that block HBV hepatocyte entry, compounds that silence or deplete the cccDNA pool, others that affect core assembly, agents that degrade RNase-H, interfering RNA molecules, and nucleic acid polymers are likely interventions in the viral life cycle. In the immunotherapy category, molecules that activate the innate immune response such as Toll-like-receptors, Retinoic acid Inducible Gene-1 (RIG-1) and stimulator of interferon genes (STING) agonists or checkpoint inhibitors, and modulation of the adaptive immunity by therapeutic vaccines, vector-based vaccines, or adoptive transfer of genetically-engineered T cells aim towards the restoration of T cell function. Future therapeutic trends would likely be a combination of one or more of the aforementioned drugs that target the viral life cycle and at least one immunomodulator.
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Project description:Over the last decade, the standard of care for the treatment of chronic hepatitis C has been the combination of pegylated-interferon-alfa (PEG-IFN) and ribavirin (RBV) which results in sustained virological response (SVR) rates of 75%-85% in patients with genotypes 2 or 3 but only of 40%-50% in patients with genotype 1. Currently, there are rapid and continuous developments of numerous new agents against hepatitis C virus (HCV), which are the focus of this review. Boceprevir and telaprevir, two first-generation NS3/4A HCV protease inhibitors, have been recently licensed in several countries around the world to be used in combination with PEG-IFN and RBV for the treatment of genotype 1 patients. Boceprevir or telaprevir based triple regimens, compared with the PEG-IFN/RBV combination, improve the SVR rates by 25%-31% in treatment-naïve genotype 1 patients, by 40%-64% in prior relapsers, by 33%-45% in prior partial responders and by 24%-28% in prior null responders. At the same time, the application of response-guided treatment algorithms according to the on-treatment virological response results in shortening of the total therapy duration to only 24 wk in 45%-55% of treatment-naïve patients. There are, however, several challenges with the use of the new triple combinations in genotype 1 patients, such as the need for immediate results of HCV RNA testing using sensitive quantitative assays, new and more frequent adverse events (anemia and dysgeusia for boceprevir; pruritus, rash and anemia for telaprevir), new drug interactions and increasing difficulties in compliance. Moreover, the SVR rates are still poor in very difficult to treat subgroups of genotype 1 patients, such as null responders with cirrhosis, while there is no benefit for patients who cannot tolerate PEG-IFN/RBV or who are infected with non-1 HCV genotype. Many newer anti-HCV agents of different classes and numerous combinations are currently under evaluation with encouraging results. Preliminary data suggest that the treatment of chronic HCV patients with well tolerated combinations of oral agents without PEG-IFN is feasible and may lead to a universal HCV cure over the next 5-10 years.
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Project description:Coronavirus disease 2019 (COVID-19), which is caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was declared by the World Health Organization (WHO) as a global pandemic on March 11, 2020. SARS-CoV-2 targets the respiratory system, resulting in symptoms such as fever, headache, dry cough, dyspnea, and dizziness. These symptoms vary from person to person, ranging from mild to hypoxia with acute respiratory distress syndrome (ARDS) and sometimes death. Although not confirmed, phylogenetic analysis suggests that SARS-CoV-2 may have originated from bats; the intermediary facilitating its transfer from bats to humans is unknown. Owing to the rapid spread of infection and high number of deaths caused by SARS-CoV-2, most countries have enacted strict curfews and the practice of social distancing while awaiting the availability of effective U.S. Food and Drug Administration (FDA)-approved medications and/or vaccines. This review offers an overview of the various types of coronaviruses (CoVs), their targeted hosts and cellular receptors, a timeline of their emergence, and the roles of key elements of the immune system in fighting pathogen attacks, while focusing on SARS-CoV-2 and its genomic structure and pathogenesis. Furthermore, we review drugs targeting COVID-19 that are under investigation and in clinical trials, in addition to progress using mesenchymal stem cells to treat COVID-19. We conclude by reviewing the latest updates on COVID-19 vaccine development. Understanding the molecular mechanisms of how SARS-CoV-2 interacts with host cells and stimulates the immune response is extremely important, especially as scientists look for new strategies to guide their development of specific COVID-19 therapies and vaccines.
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Project description:BACKGROUND: In Germany, 400 000 to 500 000 people are chronically infected with the hepatitis C virus (HCV), 70% to 80% of them with HCV genotype 1. Combined treatment with peginterferon-alfa and ribavirin leads to a sustained virologic response (SVR) in 40% to 50% of patients with genotype 1 and 70% to 80% of patients with genotypes 2 and 3. The HCV protease inhibitors boceprevir and telaprevir were approved for clinical use in Germany in 2011. METHODS: Selective literature review. RESULTS: Treatment with peginterferon and ribavirin is recommended for a variable length of time depending on the HCV genotype (24 to 72 weeks for genotype 1, 16 to 48 weeks for genotypes 2 and 3), the baseline HCV-RNA concentration (greater or less than 600 000 to 800 000 IU/mL), and the decline in HCV-RNA concentration after 4 and 12 weeks of treatment. Either boceprevir or telaprevir is given in addition to peginterferon and ribavirin. In the approval studies, these triple combinations were shown to yield higher SVR rates than dual treatment for genotype 1 (66% to 75% versus 37% to 44%). If there is a favorable early decline in HCV-RNA, the treatment can be shortened to 24 to 28 weeks in 44% to 65% of patients with genotype 1. The SVR rates in genotype 1 patients who failed previous dual therapy were 69% to 88% for prior relapsers, 52% to 59% for partial responders, and 33% for null responders. Triple combination therapy is associated with new adverse events. CONCLUSION: Individualized treatment durations are recommended for the treatment of chronic hepatitis C with peginterferon and ribavirin. Triple therapy in combination with either boceprevir or telaprevir leads to a higher rate of SVR both in previously untreated genotype 1 patients and in those who have failed prior antiviral treatment.\
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Project description:Learning new action sequences subserves a plethora of different abilities such as escaping a predator, playing the piano, or producing fluent speech. Proper initiation and termination of each action sequence is critical for the organization of behaviour, and is compromised in nigrostriatal disorders like Parkinson's and Huntington's diseases. Using a self-paced operant task in which mice learn to perform a particular sequence of actions to obtain an outcome, we found neural activity in nigrostriatal circuits specifically signalling the initiation or the termination of each action sequence. This start/stop activity emerged during sequence learning, was specific for particular actions, and did not reflect interval timing, movement speed or action value. Furthermore, genetically altering the function of striatal circuits disrupted the development of start/stop activity and selectively impaired sequence learning. These results have important implications for understanding the functional organization of actions and the sequence initiation and termination impairments observed in basal ganglia disorders.
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Project description:Viral hepatitis C is responsible for a large burden of disease worldwide. Treatment of hepatitis C infection is currently undergoing a revolution with the development of new direct acting antivirals that offer higher cure rates and fewer side effects than other medications currently available. Treatment options for children, although well-defined and evidence-based, are limited relative to adults as there are few trials regarding the use of these newly developed agents in children. With so much optimism in the development of novel therapeutic options for hepatitis C, it is timely to review and summarize the current standard of care treatment and indications for treatment of chronic hepatitis C in children. We provide here an overview of recent drug developments and their potential for use in children.
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Project description: Not available
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