At the J.P. Morgan Healthcare Conference in January, Esperion Therapeutics’ CEO Sheldon Koenig announced his vision for the cardiovascular-focused commercial company to have “multiple blockbuster products on the market” by 2040.
On Tuesday, the company took a step toward reaching its growth ambitions by acquiring Corstasis Therapeutics and its FDA-approved nasal spray Enbumyst. In September of last year, the U.S. regulator signed off on Enbumyst, a loop diuretic that relieves the edema associated with congestive heart failure, chronic kidney disease and liver disease.
Esperion is paying $75 million upfront and up to $180 million in potential milestone payments to Corstasis shareholders. Michigan-based Esperion also agreed to pay Corstasis shareholders royalties on worldwide sales of Enbumyst. Corstasis is an eight-year-old privately held company based in Nevada.
Enbumyst is a one-of-a-kind, self-administered outpatient therapy that “may help bridge the gap between oral and intravenous diuretic treatments,” the companies said in a release. It's designed to treat patients living with edema, which is the accumulation of fluid in the body’s tissues that causes swelling.
“This acquisition represents a compelling and strategically aligned opportunity that accelerates Esperion’s momentum and advances our long-term Vision 2040,” Koenig said in a 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 approval 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 tablet form to manage chronic edema or as a hospital-administered injection in response to sudden edema attacks.
Enbumyst will primarily compete with MannKind and its loop diuretic Furoscix. In a deal that resembles the Esperion-Corstatis buyout, MannKind paid $360 million upfront in August of last year to acquire scPharmaceuticals and Furoscix, which was approved to treat edema in heart failure patients in 2022 and added a new indication last year to treat those with CKD.
Furoscix treats fluid overload by way of an at-home, on-body infuser that administers the drug over a five-hour period. It generated sales of $28 million in the first half of 2025. With its larger commercial infrastructure, MannKind believes it can boost its sales.
In an investor presentation (PDF) on Tuesday, Esperion said the efficacy of Enbumyst is “comparable” to that of Furoscix but that the Corstasis nasal spray is significantly easier to use.
The companies expect the deal to close in the second quarter.
In justifying the deal, Esperion said Enbumyst “addresses a large and growing population whose medical needs align directly with Esperion’s commercial and pipeline focus.” The company projects its addressable opportunity in the U.S. with Enbumyst at $4.6 billion, according the investor presentation.
Esperion has an interesting history. It was founded in 1998 by Roger Newton, M.D., who was instrumental in the development of Pfizer’s cholesterol drug Lipitor. In 2004, Pfizer acquired Esperion for $1.3 billion, but, four years later, in a restructuring crunch, it turned the company and its assets back over to Newton.
Esperion, which went public in 2013, has two products on the market—Nexletol and Nexlizet—that reduce LDL cholesterol. In January, at the JPM event, Esperion estimated its 2025 revenue will land between $400 million and $408 million, with product sales between $156 million and $160 million and the rest of its revenue generated through collaborations.
Esperion has several partners around the world including Daiichi Sankyo in Europe, CSL in Australia, Otsuka in Japan, HLS Therapeutics in Canada and Neopharm in Israel.