REVIEW Open AccessComparison of the efficacy of tenofovir andadefovir in the treatment of chronic hepatitis B:A Systematic ReviewShu-Shan Zhao 1,2,3† , Lan-Hua Tang 1,2,4† , Xia-Hong Dai 1 , Wei Wang 5 , Rong-Rong Zhou 1 , Li-Zhang Chen 6* ,Xue-Gong Fan 1*AbstractChronic viral hepatitis B remains a global public health concern. Currently, several drugs, such as tenofovir andadefovir, are recommended for treatment of patients with chronic hepatitis B. tenofovir is a nucleoside analog withselective activity against hepatitis b virus and has been shown to be more potent in vitro than adefovir. But theresults of trials comparing tenofovir and adefovir in the treatment of chronic hepatitis B were inconsistent. However,there was no systematic review on the comparison of the efficacy of tenofovir and adefovir in the treatment ofchronic hepatitis B. To evaluate the comparison of the efficacy of tenofovir and adefovir in the treatment of chronichepatitis B we conducted a systematic review and meta-analysis of clinical trials. We searched PUBMED, Web ofScience, EMBASE, CNKI, VIP database, WANFANG database, the Cochrane Central Register of Controlled Trials and theCochrane Database of Systematic Review. Finally six studies were left for analysis which involved 910 patients in total,of whom 576 were included in tenofovir groups and 334 were included in adefovir groups. At the end of 48-weektreatment, tenofovir was superior to adefovir at the HBV-DNA suppression in patients[RR = 2.59; 95%CI(1.01-6.67),P = 0.05]. While there was no significant difference in the ALT normalization[RR = 1.15; 95%CI(0.96-1.37), P = 0.14],HBeAg seroconversion[RR = 1.32; 95%CI(1.00-1.75), P = 0.05] and HBsAg loss rate[RR = 1.19; 95%CI(0.74-1.91),P = 0.48]. More high-quality, well-designed, randomized controlled, multi-center trails are clearly needed to guideevolving standards of care for chronic hepatitis B.1. IntroductionChronic hepatitis B virus (HBV) infection is a seriousglobal public health problem associated with cirrhosis,liver failure and hepatocellular carcinoma (HCC) [1]. Ofthe two billion people who have been infected, morethan 350 million have chronic hepatitis [2]. Severalmajor advances in the treatment of chronic hepatitis B(CHB) have been made over the last several years. Cur-rently, several drugs are recommended for treatment ofpatients with CHB. These drugs can be divided into twomain groups based on their mechanism of action,namely immunomodulatory drugs like alpha interferonsand antiviral drugs including lamivudine(LAM), telbivu-dine(LdT), entecavir(ETV), adefovir(ADV), and tenofovir(TDF) [3].Adefovir dipivoxil, an acylic phosphonate, is a nucleo-tide analog licensed for the treatment of HBV, which isactive against both negative and positive HBeAg [4,5].Furthermore, it has been shown that ADV has an excel-lent activity against wild-type as well as LAM-resistantHBV strains [6,7]. However, ADV has low HBeAg sero-conversion rate which was only 12%, less potencytoward HBV DNA suppression and a few drawbacksincluding nephrotocicity for those who are at risk forrenal dysfunction [5]. Meanwhile at the licensed dose of10 mg/day ADV is not a highly potent drug [8]. But theadvantage of ADV was the low rates of resistance. Incontrast to LAM, after 2 and 4 years of ADV treatmentonly 3%, 18% of patients exhibit resistance respectively[9]. In addition, both the ADV mutations, N236T and* Correspondence: clzhang2008@yahoo.cn; xgfan@hotmail.com† Contributed equally1 Department of Infectious Diseases, Xiangya Hospital, Central SouthUniversity, Changsha, Hunan, PR China6 School of Public Health, Central South University, Changsha, Hunan, PRChinaFull list of author information is available at the end of the articleZhao et al. Virology Journal 2011, 8:111http://www.virologyj.com/content/8/1/111© 2011 Zhao et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative CommonsAttribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction inany medium, provided the original work is properly cited.
