The Significance of HBV-miR-3 in Predicting the Efficacy of Nucleoside Analogue Therapy in Patients with Chronic Hepatitis B

BACKGROUND Hepatitis B virus (HBV) is a major global health threat, with chronic infection affecting 300 million people and causing 800,000 annual deaths from complications like cirrhosis and hepatocellular carcinoma, while nucleoside analogs (NAs)—key antiviral therapies—cannot eliminate covalently closed circular DNA (cccDNA) and require long-term use with varying safety profiles. HBV-encoded microRNA-3 (HBV-miR-3), a functionally diverse viral miRNA linked to viral replication, immune evasion, and carcinogenesis with predictive value for pegylated interferon-α efficacy, has an unexplored role in evaluating NA therapy. AIM To investigate the predictive significance and advantages of HBV-miR-3 levels for NA therapeutic efficacy through a randomized clinical trial of patients receiving long-term NA therapy. METHODS This registered randomized trial (NCT03903796) included 53 adults with chronic HBV infection (HBsAg-positive ≥6 months, HBV DNA ≥2×10⁴ IU/mL) without concurrent infections or advanced liver disease. Patients were randomized 2:1 to TMF (25 mg/day) or TDF (300 mg/day) for 48 weeks, followed by TMF monotherapy up to week 144. Serum HBV-miR-3, HBV DNA, HBV RNA, HBsAg, and HBeAg were quantified using real-time PCR at baseline and follow-ups (weeks 12, 24, 48, 72, 96, 144). Statistical analyses included t-tests, ANOVA, correlation analyses, logistic regression, and receiver operating characteristic (ROC) curves to assess predictive performance. RESULTS Baseline characteristics were balanced between TMF and TDF groups. At week 48, patients with undetectable HBV DNA (DNA-negative group) had significantly lower baseline HBV-miR-3, HBV DNA, HBV RNA, and HBeAg levels, and were older, compared to the DNA-positive group. Over 144 weeks, HBV-miR-3, HBV DNA, HBV RNA, HBsAg, and HBeAg declined more markedly in the DNA-negative group. HBV-miR-3 showed strong correlations with HBV DNA, HBV RNA, and HBeAg during early treatment (≤24 weeks). ROC analyses revealed HBV-miR-3 at baseline, week 12, and week 24 independently predicted week-48 HBV DNA negativity (positive predictive values [PPV] 74.5%, 73.3%, 77.1%, respectively), with performance comparable to HBV RNA and superior to HBsAg. Notably, combining HBV-miR-3 with HBV DNA yielded higher PPVs (up to 100% at week 12). CONCLUSION HBV-miR-3 is closely associated with HBV replication and serves as a robust predictor of HBV DNA virological response during NA therapy.