Tune Therapeutics’ TUNE-401 epigenome editing therapy advanced with strong early clinical signals in a phase 1 study, reporting antiviral activity and safety data for its approach to add repressive epigenetic marks to hepatitis B virus cccDNA. “Epigenome editing” is a strategy that modifies gene-expression control signals rather than directly cutting the viral genome. The results reinforce growing interest in functional cure concepts for chronic hepatitis B, where key barriers include maintaining suppression after treatment stops. Early-stage safety data remain central for this modality, given the need to ensure edits are controlled and localized. For biotech watchers, the event is notable because it combines a new mechanism class with the trial endpoint framing typical of next-generation curative programs—antiviral activity plus tolerability in early humans.