Regeneron agreed to a $150 million collaboration with Tessera Therapeutics to co-develop TSRA-196, Tessera’s in vivo gene-writing candidate for alpha-1 antitrypsin deficiency (AATD). The pact gives Regeneron development and commercialization rights and accelerates Tessera’s clinic-ready program into a partner-led development pathway. The deal pairs Regeneron’s late‑stage development and commercial capabilities with Tessera’s proprietary gene-writing platform, a non‑classic editing approach billed as a potential one‑time therapy. The arrangement signals continued big‑biotech appetite for next‑generation genetic medicines and shifts near‑clinic gene‑writing risk onto an established developer.