ABSTRACT
@#Worldwide, an estimated two billion people have evidence of HBV infection, and approximately 240 million have CHB. In April 2017, EASL added a drug newly approved for treatment of CHB, tenofoviralafenamide (TAF) to their list of recommended first-line therapies. Treatment with these therapies can achieve sustained suppression of HBV DNA replication, decreases in inflammation, and histological activity that decrease the risk of cirrhosis and hepatocellular carcinoma in both cirrhotic and noncirrhotic patients and, ultimately, of CHB-associated mortality [1, 2]. However, recent advances in understanding the HBV life cycle have enabled multiple, novel therapeutic targets to be identified and new therapies of direct-acting antiviral (DAAs) and host-targeting agents (HTAs) are indevelopment.</br> In most clinical trials, TAF was non-inferior to TDF in achieving HBV DNA levels below 29 IU/ml.No amino-acid substitutions associated with viral breakthrough were detected by deep sequencing, and no resistance to TAF.With clear evidence from major studies showing that TAF is safe, tolerable, and non-inferior to TDF, its recommendation as a first-line therapy is appropriate.</br> Long-term safety is an important consideration in the therapeutic management of patients with CHB because treatment is often life-long.</br> The efficacy of TAF in patients with resistance mutations associated with older nucleos(t)ide analogues is unclear. Although no evidence of TAF or TDF resistance was detected in the phase III studies through 96 weeks of treatment, very small numbers of patients had baseline mutations indicating resistance to lamivudine, adefovir or entecavir and efficacy data specifically for this group is not available.
ABSTRACT
Introduction@#Worldwide, an estimated two billion people have evidence of HBV infection, and approximately 240 million have CHB. In this study, a representative group of Mongolian adults was tested for hepatitis B virus (HBV) in 2017. The prevalence estimates of HBV the general Mongolian adult population were found to be 11.1%, respectively.</br> In April 2017, EASL added a drug newly approved for treatment of CHB, tenofovir alafenamide (TAF) to their list of recommended first-line therapies. The requirement for long-term therapy in chronic HBV highlights the importance of these efficacy and safety trends, however their true clinical relevance is yet to be established and further studies with long-term follow up and real-world clinical data are needed.@*Goal@#Evaluate for result of tenofovir alafenamide in the treatment of chronic hepatitis B infection.@*Materials and Methods@#The clinical trials have evaluated TAF in HBeAg-positive and HBeAg-negative chronic HBV patients. The trials have similar designs and are randomized, double blind, non-inferiority studies. The primary efficacy endpoint was the proportion of patients with HBV DNA<29 IU/ml at week 24 and 48. Other prespecified efficacy endpoints were the proportion of patients with HBsAg seroncoversion to anti-HBs at week 24 and 48. Key secondary safety end- points at week 24 and 48 included the percentage change in T-score, and Z-score bone mineral density (BMD), percentage change in BMD and change from baseline serum creatinine.@*Results@#The primary efficacy endpoint, an HBV DNA level <29 IU/ml at week 24, was achieved by 120 (59.1%) of 203 patients receiving TAF, which was non-inferior to the 63 (55.2%) of 114 patients receiving TDF who had an HBV DNA<29 IU/ml. After 24 weeks of treatment, patients receiving TAF had significantly smaller reductions in bone mineral density (BMD) compared with patients receiving TDF.@*Conclusion@#The development of TAF, specifically designed to deliver potent antiviral activity but with an improved safety profile compared with TDF, is therefore timely.