easily be higher when long-term therapy is needed.

Which Is the Better One? Peg-interferon ? Or Nucleoside Analogues?
Peg-interferon and nucleoside analogues are the most major options of antiviral therapy in chronic HBV infected patients. When deciding on the antiviral drug to be given, several factors have to be taken into account. Professor Harry L.A. Janssen of University Medical Center, Rotterdam, The Netherlands compared the advantages and disadvantages of  PEG-IFN with those of nucleoside analogues. The major advantage of PEG-IFN is the higher chance of achieving sustained response compared to nucleos(t)ide analogues with a finite duration of therapy while the disadvantages are the subcutaneous administration and the frequent occurrence of side effects. On the contrast, The major advantage of nucleos(t)ide analogues are the favourable tolerability and the oral administration. Disadvantages are the long duration of therapy and the subsequent risk of antiviral resistance. Besides, the costs of a one-year course of nucleos(t)ide analogue therapy are lower than of PEG-IFN, but will
PEG-IFN can be considered as therapy in eligible patients because of the higher chance of achieving sustained off-treatment response compared to nucleos(t)ide analogues. Professor Harry L.A. Janssen also expound the chance of response to PEG-IFN therapy in HBeAg-positive and HBeAg-negtive patients respectively. Sustained transition to the immune-control phase (inactive HBsAg carrier state) can be achieved in 30% of HBeAg positive patients and 25% of HBeAg negative patients treated with PEG-IFN, implicating that treatment induced response is sustained in about 85% and 50% of HBeAg positive and HBeAg negative patients, respectively. Relapse occurs in at least 40% and 90% of HBeAg positive and HBeAg negative patients after discontinuation of nucleos(t)ide analogue therapy, respectively. HBeAg-positive patients with a high chance of response to PEG-IFN therapy are those with genotype A, and those with genotype B or C having serum HBV DNA below 1.0x 109 copies/ml and serum ALT above twice the upper limit of normal. In HBeAg positive patients, response rates after 24-32 weeks of treatment course seem comparable to those observed after one year, but head-to-head comparison is not available. For HBeAg-negative disease the role of genotype is less well defined. However, it has been suggested that in HBeAg-negative patients genotypes B and C were more likely to achieve a sustained virologic response than genotype D. Furthermore, low serum HBV-DNA and high ALT levels are positive predictors of response in these patients. Since early prediction of response to PEG-IFN is difficult in chronic HBV infected patients, the recommended the duration of therapy is still one year for all patients.

Professor Harry L.A. Janssen pointed out that nucleos(t)ide analogue therapy should be considered in all patients not responding to or not eligible for PEG-IFN therapy. This includes also patients with autoimmune disease, pre-existent psychiatric disorders or advanced cirrhosis. It should be emphasized that when choosing a nucleos(t)ide analogue, potency and risk of resistance play an important role. It is recommended to choose those antivirals with most potency, highest genetic barrier, least toxicity.

聚乙二醇化干扰素（PEG-IFN）及核苷（酸）类似物为目前最主要的慢性乙型肝炎抗病毒治疗方法，在选择药物时需要考虑多个方面的因素。Harry L.A. Janssen 教授比较了PEG-IFN和核苷类似物的优缺点，PEG-IFN在有限的时间内达到持续应答的机会更大，并在治疗结束后仍能维持持续应答，但需要皮下注射且易出现副作用。而核苷（酸）类似物治疗具有良好的耐受性且为口服给药，但需要长时间持续治疗且治疗后存在发生抗病毒耐药的风险。因此，推荐选择强效、高基因屏障和毒副作用小的药物。