Current therapies for chronic hepatitis B (CHB) have a number of limitations, and better treatment options are needed. Peginterferon alpha-2a (40 kDa) is superior to conventional interferon alpha-2a in the treatment of chronic hepatitis C. This is the first report on peginterferon alpha-2a (40 kDa) in the treatment of CHB. In this phase II study, 194 patients with CHB not previously treated with conventional interferon-alpha were randomized to receive weekly subcutaneous doses of peginterferon alpha-2a (40 kDa) 90, 180 or 270 microg, or conventional interferon alpha-2a 4.5 MIU three times weekly. Twenty-four weeks of therapy were followed by 24 weeks of treatment-free follow-up. All subjects were assessed for loss of hepatitis B e antigen (HBeAg), presence of hepatitis B antibody (anti-HBe), suppression of hepatitis B virus (HBV) DNA, and normalization of serum alanine transaminase (ALT) after follow-up. At the end of follow-up, HBeAg was cleared in 37, 35 and 29% of patients receiving peginterferon alpha-2a (40 kDa) 90, 180 and 270 microg, respectively, compared with 25% of patients on conventional interferon alpha-2a. The combined response (HBeAg loss, HBV DNA suppression, and ALT normalization) of all peginterferon alpha-2a (40 kDa) doses combined was twice that achieved with conventional interferon alpha-2a (24%vs 12%; P = 0.036). All treatment groups were similar with respect to frequency and severity of adverse events. These results indicate that peginterferon alpha-2a (40 kDa) is superior in efficacy to conventional interferon alpha-2a in chronic hepatitis B based on clearance of HBeAg, suppression of HBV DNA, and normalization of ALT.

Of the estimated 50 million new cases of hepatitis B virus (HBV) infection diagnosed annually, 5-10% of adults and up to 90% of infants will become chronically infected, 75% of these in Asia where hepatitis B is the leading cause of chronic hepatitis, cirrhosis and hepatocellular carcinoma (HCC). In Indonesia, 4.6% of the population was positive for HBsAg in 1994 and of these, 21% were positive for HBeAg and 73% for anti-HBe; 44% and 45% of Indonesian patients with cirrhosis and HCC, respectively, were HBsAg positive. In the Philippines, there appear to be two types of age-specific HBsAg prevalence, suggesting different modes of transmission. In Thailand, 8-10% of males and 6-8% of females are HBsAg positive, with HBsAg also found in 30% of patients with cirrhosis and 50-75% of those with HCC. In Taiwan, 75-80% of patients with chronic liver disease are HBsAg positive, and HBsAg is found in 34% and 72% of patients with cirrhosis and HCC, respectively. In China, 73% of patients with chronic hepatitis and 78% and 71% of those with cirrhosis and HCC, respectively, are HBsAg positive. In Singapore, the prevalence of HBsAg has dropped since the introduction of HBV vaccination and the HBsAg seroprevalence of unvaccinated individuals over 5 years of age is 4.5%. In Malaysia, 5.24% of healthy volunteers, with a mean age of 34 years, were positive for HBsAg in 1997. In the highly endemic countries in Asia, the majority of infections are contracted postnatally or perinatally. Three phases of chronic HBV infection are recognized: phase 1 patients are HBeAg positive with high levels of virus in the serum and minimal hepatic inflammation; phase 2 patients have intermittent or continuous hepatitis of varying degrees of severity; phase 3 is the inactive phase during which viral concentrations are low and there is minimal inflammatory activity in the liver. In general, patients who clear HBeAg have a better prognosis than patients who remain HBeAg-positive for prolonged periods of time. The outcome after anti-HBe seroconversion depends on the degree of pre-existing liver damage and any subsequent HBV reactivation. Without pre-existing cirrhosis, there may be only slight fibrosis or mild chronic hepatitis, but with pre-existing cirrhosis, further complications may ensue. HBsAg-negative chronic hepatitis B is a phase of chronic HBV infection during which a mutation arises resulting in the inability of the virus to produce HBeAg. Such patients tend to have more severe liver disease and run a more rapidly progressive course. The annual probability of developing cirrhosis varies from 0.1 to 1.0% depending on the duration of HBV replication, the severity of disease and the presence of concomitant infections or drugs. The annual incidence of hepatic decompensation in HBV-related cirrhosis varies from 2 to 10% and in these patients the 5-year survival rate drops dramatically to 14-35%. The annual risk of developing HCC in patients with cirrhosis varies between 1 and 6%; the overall reported annual detection rate of HCC in surveillance s...

The risk factors and settings for non-alcoholic fatty liver disease (NAFLD) in Asians are reviewed comprehensively. Based particularly on large community-based studies using ultrasonography, case-control series and prospective longitudinal studies, the prevalence of NAFLD in Asia is between 12% and 24%, depending on age, gender, locality and ethnicity. Further, the prevalence in China and Japan has nearly doubled in the last 10-15 years. A detailed analysis of these data shows that NAFLD risk factors for Asians resemble those in the West for age at presentation, prevalence of type 2 diabetes mellitus (T2DM) and hyperlipidemia. The apparent differences in prevalence of central obesity and overall obesity are related to criteria used to define waist circumference and body mass index (BMI), respectively. The strongest associations are with components of the metabolic syndrome, particularly the combined presence of central obesity and obesity. Nonalcoholic fatty liver disease appears to be associated with long-standing insulin resistance and likely represents the hepatic manifestation of metabolic syndrome. Not surprisingly therefore, Asians with NAFLD are at high risk of developing diabetes and cardiovascular disease. Conversely, metabolic syndrome may precede the diagnosis of NAFLD. The increasing prevalence of obesity, coupled with T2DM, dyslipidemia, hypertension and ultimately metabolic syndrome puts more than half the world's population at risk of developing NAFLD/non-alcoholic steatohepatitis/cirrhosis in the coming decades. Public health initiatives are clearly imperative to halt or reverse the global 'diabesity' pandemic, the underlying basis of NAFLD and metabolic syndrome. In addition, a perspective of NAFLD beyond its hepatic consequences is now warranted; this needs to be considered in relation to management guidelines for affected individuals.

Primary liver cancer, particularly hepatocellular carcinoma (HCC) remains a significant disease worldwide. It is among the top three causes of cancer death in the Asia Pacific region because of the high prevalence of its main etiological agents, chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. In this region, the incidence of HCC has been static over recent decades. Older age is a major risk factor; the incidence increasing sharply after age 40 years. There is a male predilection, with male to female ratio of 3:1, except in elderly Japanese with equal sex incidence or female predominance. In most Asia-Pacific countries, chronic HBV infection accounts for 75-80% of cases; Japan, Singapore and Australia/New Zealand are exceptions because of higher prevalence of HCV infection. In spite of advances in surgery, liver transplantation and newer pharmaco/ biological therapies, the survival rate has improved only slightly over recent decades, and this could be attributable to earlier diagnosis ('lead-time bias'). The majority of patients present with advanced diseases, hence reducing the chance of curative treatment. The importance of HCC may decrease in two to three decades when the prevalence of chronic HBV infection decreases as a result of the universal HBV vaccination programs implemented in late 1980s in most Asia-Pacific countries, and because of reduced incidence of medical transmission of HCV. However, transmission of HCV by injection drug use, and rising prevalence of obesity and diabetes, both independent risk factors for HCC, may partly offset this decline.

The entire nucleotide sequences of 70 hepatitis B virus (HBV) isolates of genotype B (HBV/B), including 38 newly determined and 32 retrieved from the international DNA database (DDBJ/EMBL/GenBank), were compared phylogenetically. Two subgroups of HBV/B were identified based on sequence divergence in the precore region plus the core gene, one with the recombination with genotype C and the other without it. The analysis over the entire genome of HBV/B by the SimPlot program located the recombination with genotype C in the precore region plus the core gene spanning nucleotide positions from 1740 to 1838 to 2443 to 2485. Within this genomic area, HBV/B strains with the recombination had higher nucleotide and amino acid homology to genotype C than those without the recombination (96.9 versus 91.1% in nucleotides and 97.0 versus 92.9% in amino acids). There were 29 HBV/B strains without the recombination, and they were all recovered from carriers in Japan. The remaining 41 HBV/B isolates having the recombination with genotype C were from carriers in China (12 strains), Hong Kong (3 strains), Indonesia (4 strains), Japan (3 strains), Taiwan (4 strains), Thailand (3 strains), and Vietnam (12 strains). Due to the frequency of the distribution of HBV/B without the recombination (29 of 32 isolates, or 91%) and the fact that it was exclusive to Japan, it was provisionally classified into the Bj (j standing for Japan) subgroup, and HBV/B with the recombination was classified into the Ba (a for Asia) subgroup. Virological differences between HBV/Bj and HBV/Ba may be reflected in the severity of clinical disease in the patients infected with HBV of genotype B, which seems to be under strong geographic influences in Asia.