Farag MS, van Campenhout MJH, Pfefferkorn M, et al. - Researchers analyzed the kinetics of hepatitis B virus RNA (HBV-RNA), a novel serum biomarker, following pegylated interferon (PEG-IFN) treatment. Further, they investigated its potential role as a predictor to response in HBeAg-negative chronic hepatitis B (CHB) patients. HBV-RNA correlates with the transcription of intrahepatic covalently closed circular (cccDNA) which is a significant target for PEG-IFN and novel therapies for a functional cure. They determined HBV-RNA levels in 133 HBeAg-negative CHB patients treated with PEG-IFN α-2a for 48 weeks in an international randomized controlled trial (PARC study). At baseline, they identified mean value of HBV-RNA of 4.4 (SD 1.2) log₁₀ c/mL. Observation revealed a fast and significant decline in HBV-RNA during PEG-IFN treatment for HBeAg-negative CHB that correlates with treatment response and HBsAg-loss at long-term follow-up.