Tessera Therapeutics confirmed it will begin the first human trial of its in vivo gene‑writing platform, testing an approach intended to install permanent genetic changes without double-strand breaks. The Phase 1 study targets a rare genetic disease (alpha‑1 antitrypsin deficiency was cited in company materials) and represents the platform’s transition from preclinical validation to clinical testing. Tessera’s gene writing uses proprietary enzymology and delivery modalities designed to write therapeutic sequences directly into patient genomes; the trial will provide initial safety, dosing and target‑engagement data crucial to the platform’s broader therapeutic roadmap.