Tessera Therapeutics confirmed it will begin its first-in-human trial next month for an in vivo gene‑writing platform, targeting adults with a rare genetic disease (alpha‑related condition reported in the firm’s release). The move converts long‑running preclinical work into clinical execution and marks one of the earliest human tests of a gene‑writing modality that writes DNA sequences in situ rather than delivering a replacement gene. Tessera’s platform aims to install or rewrite genomic sequences directly in patients’ cells, a step beyond traditional gene therapy vectors and base editors. The company plans to watch safety and on‑target writing efficiency closely in the first cohort and expects the readouts to shape future indications and manufacturing approaches. Clarification: gene writing differs from editing in that it can inscribe new sequences into the genome without relying solely on endogenous repair pathways, potentially enabling larger or more complex corrections.