Regeneron and Tessera Therapeutics struck a deal worth $150 million to co-develop TSRA-196, Tessera’s near-clinic in vivo gene-writing candidate for alpha-1 antitrypsin deficiency (AATD). Regeneron will share development and commercialization responsibilities under the partnership, signaling big-pharma commitment to next-generation gene-writing approaches that aim to install permanent genomic changes in target tissues. Gene writing is a precision approach distinct from conventional editing: it aims to write corrective DNA sequences directly into the genome without reliance on donor template therapies. The alliance gives Tessera both capital and Regeneron’s development scale; Regeneron gains exposure to a potentially one-time curative modality. Observers say the deal reflects a rush among large biotechs to secure rights to emerging in vivo gene technologies.