Tenofovir alafenamide fumarate (TAF) has high plasma stability resulting in fewer renal adverse events compared to tenofovir disoproxil fumarate (TDF) in chronic hepatitis B (CHB) patients. We aimed to study the effectiveness and renal safety of TAF in a real‐world setting, in patients with or without compromised kidney function. CHB patients (Nucleos(t)ide Analogue [NA]‐naïve or experienced) who received TAF >1 year from 11 academic institutions as part of the Canadian Hepatitis B Network (CanHepB) were included. Kidney function was measured by estimated glomerular filtration rate (eGFR) as per Cockcroft‐Gault. Patients were followed for up to 160 weeks. Of 176 patients receiving TAF, 143 switched from NA (88% TDF), and 33(19%) were NA naïve. Majority of NA‐naïve patients (75%) achieved undetectable HBV DNA after one year of TAF treatment. Majority of patients with eGFR <60 mL/min who had renal deterioration during TDF (76%) reversed to eGFR increase after one year of TAF (p=0.009). Among patients with stage 2 chronic kidney disease (CKD) (eGFR 60–89), the estimated eGFR decline during TDF was halted after switching to TAF (p=0.09). NA‐experienced patients with abnormal ALT before TAF showed a significant decline after switching to TAF: −0.005 [−0.006 – −0.004] log10 ULN U/L/month, p<0.001). In CHB patients, TAF was safe, well‐tolerated and effective in this real‐world cohort. Switching to TAF led to improved kidney function, particularly in those with stage 2 CKD, which suggests that the indication for TAF in the guidelines could be extended to patients with an eGFR higher than 60 mL/min.

Background Hepatitis B virus RNA (HBV-RNA) is a novel serum biomarker that correlates with transcription of intrahepatic covalently closed circular (cccDNA), which is an important target for pegylated interferon (PEG-IFN) and novel therapies for functional cure. We studied HBV-RNA kinetics following PEG-IFN treatment and its potential role as a predictor to response in HBeAg-negative chronic hepatitis B (CHB) patients. Methods HBV-RNA levels were measured in 133 HBeAg-negative CHB patients treated in an international randomized controlled trial (PARC study). Patients received PEG-IFN α-2a for 48 weeks. HBV-RNA was measured from baseline through week 144. Response was defined as HBV-DNA &lt;2000 IU/mL and ALT normalization at week 72. Kinetics of HBV-RNA were compared with HBV-DNA, HBsAg, and HBcrAg. Results Mean HBV-RNA at baseline was 4.4 (standard deviation [SD] 1.2) log10 c/mL. At week 12, HBV-RNA declined by −1.6 (1.1) log10 c/mL. HBV-RNA showed a greater decline in responders compared to nonresponders early at week 12 (−2.0 [1.2] vs −1.5 [1.1] log10 c/mL, P = .04). HBV-RNA level above 1700 c/mL (3.2 log10 c/mL) had a negative predictive value of 91% at week 12 and 93% at week 24 (P = .01) for response. Overall, HBV-RNA showed a stronger correlation with HBV-DNA and HBcrAg (.82 and .80, P &lt; .001) and a weak correlation with HBsAg (.25). At week 12, HBV-RNA was significantly lower among patients with lower HBsAg (&lt;100 IU/mL) or HBsAg loss at week 144. Conclusions During PEG-IFN treatment for HBeAg-negative CHB, HBV-RNA showed a fast and significant decline that correlates with treatment response and HBsAg loss at long-term follow-up. Clinical Trials Registration NCT00114361