Regeneron and Tessera struck a development and commercialization agreement that funnels roughly $150 million toward Tessera’s in‑vivo gene‑writing candidate TSRA‑196 for alpha‑1 antitrypsin deficiency (AATD). The deal gives Regeneron near‑term rights and shared development responsibilities while accelerating Tessera’s path to the clinic. TSRA‑196 uses Tessera’s gene‑writing platform to install corrective sequences directly in patient tissues, a concept distinct from classic CRISPR nuclease editing. Gene writing aims to write replacement DNA without double‑stranded breaks, which proponents say could reduce some off‑target risks. The partnership pairs Regeneron’s clinical and commercial infrastructure with Tessera’s platform technology, signaling Big Biotech’s willingness to underwrite next‑generation in‑vivo gene approaches. Investors and developers will watch the early clinic readouts for safety and durable expression signals.