Regeneron agreed to a $150 million upfront investment and equity purchase to partner with Tessera on TSRA-196, a gene-writing program aimed at correcting the mutation that causes alpha-1 antitrypsin deficiency (AATD). Tessera will lead the first-in-human trial and Regeneron will share global development and commercialization responsibilities, with near- and mid-term milestones topping an additional $125 million. The partners said TSRA-196 uses Tessera’s Gene Writing platform — a retrotransposon-based system coupled to reverse transcriptase — to make precise in vivo DNA corrections. Tessera plans IND/CTA filings by year-end based on strong in vivo data, and the deal structures equal cost sharing and profit split thereafter. For the rare-disease field, the transaction signals big-pharma willingness to underwrite next-generation genome-editing modalities and accelerates an AATD program that targets liver and lung manifestations with a potential one-time durable therapy.