At the JPMorgan Healthcare Conference in January, Esperion Therapeutics CEO Sheldon Koenig announced a vision for the cardiovascular-focused commercial company to have “multiple blockbuster products on the market” by 2040.
The company took a step toward achieving its growth goals Tuesday by acquiring Corstasis Therapeutics and the FDA-approved nasal spray Enbumyst. Last September, U.S. regulators approved Enbumyst, a loop diuretic that reduces edema associated with congestive heart failure, chronic kidney disease, and liver disease.
Esperion will pay Corstasis shareholders $75 million upfront and up to $180 million in potential milestone payments. Michigan-based Esperion also agreed to pay Colstasis shareholders royalties on worldwide sales of Enbumyst. Corstasis is an 8-year-old privately held company based in Nevada.
Enbumyst is a unique outpatient therapy that “may help bridge the gap between oral and intravenous diuretic therapy,” the companies said in a release. It is designed to treat patients suffering from edema, which is a buildup of fluid within the body’s tissues that causes swelling.
“This acquisition represents an attractive and strategically aligned opportunity to accelerate Esperion’s momentum and advance our long-term Vision 2040,” Koenig said in the release. “Enbumyst brings meaningful innovation to millions of patients who continue to struggle with the daily burden of diuretic therapy. Enbumyst’s novel intranasal delivery, established regulatory approvals, and expanding clinical footprint make it a natural fit for our cardiovascular franchise.”
Enbumyst is a nasal spray formulation of the drug bumetanide, which entered the U.S. market in 1983 as Roche’s Bumex. For decades, patients have used Bumex in pill form to manage chronic edema or as an injection in the hospital in response to sudden attacks of edema.
Enbumyst primarily competes with MannKind and its loop diuretic Furoscix. In a deal similar to the Esperion and Colstatis acquisitions, Mankind paid $360 million upfront to acquire SC Pharmaceuticals and Flosix last August. Flosix was approved in 2022 to treat edema in heart failure patients, and last year it added a new indication for the treatment of CKD patients.
Furoscix treats fluid overload by administering the drug over five hours using a body-worn injector for home use. Revenue for the first half of 2025 was $28 million. MannKind believes its large commercial infrastructure will allow it to increase sales.
In an investor presentation (PDF) on Tuesday, Esperion said Enbumyst’s efficacy is “comparable” to that of Furoscix, but that Corstasis nasal spray is much easier to use.
The companies expect the deal to close in the second quarter.
In justifying the deal, Esperion said Embumist “serves a large and growing population whose medical needs align directly with Esperion’s commercial and pipeline focus.” The company projects a viable U.S. opportunity with Enbumyst at $4.6 billion, according to an investor presentation.
Esperion has an interesting history. It was founded in 1998 by Dr. Roger Newton, who helped develop Pfizer’s cholesterol drug Lipitor. In 2004, Pfizer acquired Esperion for $1.3 billion, but four years later, in a restructuring crisis, it turned the company and its assets over to Newton.
Esperion, which went public in 2013, markets two products that lower LDL cholesterol: Nexletol and Nexlisette. At a JPM event in January, Esperion estimated that 2025 sales would be $400 million to $408 million, product sales would be $156 million to $160 million, and the remaining revenue would be generated through collaborations.
Esperion has multiple partners around the world, including Daiichi Sankyo in Europe, CSL in Australia, Otsuka Pharmaceutical in Japan, HLS Therapeutics in Canada, and Neopharm in Israel.
