Regeneron agreed to a strategic collaboration with Tessera Therapeutics, investing $150 million to develop TSRA‑196, a gene‑writing program targeting alpha‑1 antitrypsin deficiency (AATD). Tessera will lead the first‑in‑human trial and Regeneron will take later‑stage development and commercialization responsibilities. The deal includes upfront cash and equity to Tessera plus up to $125 million in near‑ and mid‑term milestones. Tessera’s Gene Writing platform uses a retrotransposon‑based system and reverse transcriptase to perform targeted DNA changes in vivo, an approach the company says can enable durable correction for monogenic diseases. Regeneron and Tessera plan IND and CTA filings before year‑end. The collaboration signals major pharma interest in nonviral, in‑situ gene correction approaches and will accelerate clinical testing of gene‑writing technologies.