Esperion buys Corstasis for USD255M to launch Enbumyst nasal spray for edema

USA—Michigan-based Esperion has agreed to acquire Corstasis, an eight-year-old privately held Nevada company, in a deal valued at up to USD255 million.

The pharmaceutical company will pay USD 75 million upfront to Corstasis shareholders, with an additional USD 180 million available through potential milestone payments.

Esperion also committed to paying royalties on worldwide sales of Enbumyst, Corstasis’s flagship product.

Enbumyst represents a novel approach to treating edema, the accumulation of fluid in body tissues that causes swelling.

The self-administered nasal spray therapy bridges the gap between oral and intravenous diuretic treatments, offering patients an outpatient option for managing their condition.

Strategic alignment with company vision

Esperion’s leadership views the acquisition as a strategically aligned opportunity that accelerates the company’s momentum toward its Vision 2040 goals.

The addition of Enbumyst brings meaningful innovation to millions of patients who struggle daily with diuretic therapy management.

The nasal spray’s novel intranasal delivery system, established regulatory approval, and expanding clinical applications make it a natural complement to Esperion’s existing cardiovascular franchise.

The company estimates the United States’ addressable market opportunity for Enbumyst at USD 4.6 billion.

Product background and market position

Enbumyst contains bumetanide, a drug that entered the U.S. market in 1983 as Roche’s Bumex.

Patients have relied on Bumex in tablet form for chronic edema management and as a hospital-administered injection for sudden edema attacks for decades.

The product will primarily compete with MannKind’s Furoscix, another loop diuretic that treats edema in heart failure patients.

MannKind acquired Furoscix through its USD 360 million purchase of scPharmaceuticals in August 2024.

Furoscix uses an at-home, on-body infuser that administers treatment over five hours and generated USD 28 million in sales during the first half of 2025.

Esperion maintains that Enbumyst delivers efficacy comparable to Furoscix while offering significantly easier administration for patients.

Company heritage and current portfolio

Roger Newton founded Esperion in 1998 after playing an instrumental role in developing Pfizer’s cholesterol drug Lipitor.

Pfizer acquired Esperion for USD 1.3 billion in 2004, but returned the company and its assets to Newton four years later during a restructuring.

Since going public in 2013, Esperion has marketed two LDL cholesterol-reducing products: Nexletol and Nexlizet.

The company projected 2025 revenue of USD400 million to USD408 million in January, with product sales contributing USD156 million to USD160 million and collaborative partnerships generating the remainder.

Esperion maintains partnerships with pharmaceutical companies worldwide, including Daiichi Sankyo in Europe, CSL in Australia, Otsuka in Japan, HLS Therapeutics in Canada, and Neopharm in Israel.

The companies expect the Corstasis acquisition to close in the second quarter of 2025.