Regeneron Pharmaceuticals, Inc. (REGN) is backing a promising gene therapy collaboration with a serious check. The company announced Monday it's partnering with Tessera Therapeutics to jointly develop and commercialize TSRA-196, an experimental treatment targeting alpha-1 antitrypsin deficiency.

If you haven't heard of AATD, here's the deal: It's an inherited genetic disorder where your body doesn't produce enough alpha-1 antitrypsin protein, which normally protects your lungs and liver. Without enough of this protein, patients can develop serious damage to either or both organs. It's rare but not insignificant, affecting approximately 200,000 people across the U.S. and Europe.

What makes TSRA-196 interesting is that it's designed as a one-and-done solution. Rather than managing symptoms indefinitely, this gene writing therapy aims to precisely correct the underlying genetic mutation responsible for AATD, restoring the body's ability to produce functional AAT protein. Think of it as fixing the typo in your DNA rather than just dealing with the consequences.

Tessera is moving quickly toward human trials. The company expects to file an Investigational New Drug application and multiple Clinical Trial Applications with the FDA by the end of this year, which would clear the path for testing in patients.

The Financial Structure

Here's how the deal breaks down: Tessera receives $150 million upfront, which includes both cash and an equity investment from Regeneron. Beyond that initial payment, Tessera can earn another $125 million through near and mid-term development milestone payments. The two companies will split worldwide development costs and any future profits equally.

As for responsibilities, Tessera will lead the first-in-human trial, while Regeneron takes charge of subsequent global development and commercialization efforts. It's a sensible division of labor that leverages Regeneron's commercial muscle with Tessera's specialized gene therapy platform.

The Science Behind It

This collaboration builds on some compelling preclinical data that Tessera presented at the American Society of Gene & Cell Therapy Annual Meeting. The results showed durable, high-fidelity genome editing of SERPINA1, the specific genetic locus responsible for AATD, in both mice and non-human primates following a single dose of TSRA-196.

What really caught attention was the precision: high liver editing specificity with no germline or off-target editing detected, plus favorable safety and tolerability using Tessera's proprietary lipid nanoparticle delivery system. In other words, the therapy appears to hit its target without causing collateral damage elsewhere in the genome.

Regeneron stock was down 3.02% at $756.40 on Monday following the announcement.