No difference in treatment response or efficacy was observed between tenofovir alafenamide (TAF) and tenofovir disoproxil fumarate (TDF) regardless of hepatitis B virus (HBV) genotype, including in patients with known resistance mutations at baseline, according to an integrated resistance analysis published in Antimicrobial Agents and Chemotherapy. Furthermore, no TAF-associated resistance substitutions associated with virologic breakthrough were found.
Researchers conducted 2 clinical trials (ClinicalTrials.gov Identifiers: NCT01940471, NCT01940341) during which 1298 patients with chronic hepatitis B (CHB) who were hepatitis e antigen positive or hepatitis e antigen negative were randomly assigned to receive either TAF (n=866) or TDF (n=432) for up to 144 weeks, followed by the option of an open-label TAF treatment up to week 384.
The patient population included in these trials represented global people with CHB and included patients who had not undergone treatment and those who had been treated and who were all infected with HBV genotypes A through D.
The researchers found that the proportion of patients achieving virus suppression (HBV DNA <69 IU/mL) was similar across treatment groups and that no substitutions associated with resistance to TAD or TDF were detected after 96 weeks.
“Overall, this study demonstrates that TAF monotherapy achieved high levels of viral suppression over 96 weeks of treatment and that no resistance to TAF developed in patients with CHB,” concluded the authors.
This study was sponsored and financially supported by Gilead Sciences, Inc.
Cathcart AL, Chan HL-Y, Bhardwaj N, et al. No resistance to tenofovir alafenamide detected through 96 weeks of treatment in patients with chronic hepatitis B [published online July 23, 2018]. Antimicrob Agents Chemother. doi: 10.1128/AAC.01064-18