Tessera Therapeutics announced it will start its first human trial next month, testing its in vivo gene writing platform in adults with a rare genetic disease (alpha‑related indication disclosed by the company). The trial marks the first clinical test of the company’s programmable gene writing approach, which seeks to install genetic sequences directly in situ without relying on traditional viral gene therapy vectors. Tessera framed the study as a milestone for the nascent gene writing field and a proof of concept for in vivo sequence installation. The company aims to generate safety and proof‑of‑mechanism data that will inform broader applications of gene writing for single‑dose, durable genetic medicines. Investors and competitors will watch delivery, editing specificity and immunogenicity findings closely.