Esperion Therapeutics has agreed to acquire Corstasis Therapeutics in a deal worth up to US$255m, adding a nasal spray treatment for heart failure-related fluid retention to its portfolio.
Under the agreement, Esperion will pay US$75m in upfront cash for all outstanding Corstasis shares. Shareholders may also receive up to US$180m in additional payments linked to regulatory and commercial milestones, plus low double-digit royalties on sales.
The deal centres on Enbumyst, a bumetanide nasal spray developed by Corstasis and now being commercialised. The drug is a loop diuretic, meaning it helps the body remove excess fluid.
The US Food and Drug Administration approved Enbumyst in September 2025 to treat oedema, or fluid retention, associated with congestive heart failure as well as liver and kidney disease in adults.
Esperion said Enbumyst is the first and only FDA-approved nasal spray diuretic. The company said the treatment offers a self-administered option that may help bridge the gap between oral and intravenous diuretic therapies for patients managing fluid overload at home.
About 6.7 million adults in the US live with congestive heart failure, and oedema is one of its most common symptoms, particularly as the disease progresses.
Esperion said the product allows it to target a US market with a potential opportunity exceeding US$4bn.
The transaction is expected to close in the second quarter of 2026.
Esperion plans to finance the acquisition through existing credit facilities and royalty monetisation of its Japanese royalties with funds managed by Athyrium Capital Management and HealthCare Royalty.
Corstasis is also developing a subcutaneous pipeline, including a multidose pen injector, which Esperion said could open further market opportunities.
Sheldon Koenig, president and chief executive officer of Esperion, said:
“This acquisition represents a compelling and strategically aligned opportunity that accelerates Esperion’s momentum and advances our long-term Vision 2040. 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.
We expect that by integrating Enbumyst into our proven commercial platform, we will drive sustained double-digit growth, strengthen our leadership in cardiovascular care, and create durable value for all of our stakeholders, from patients and providers to employees and shareholders.
Ben Esque, chief executive officer of Corstasis Therapeutics, said:
“Enbumyst was purpose-built in partnership with the cardiology community to address a clear unmet need. Today’s acquisition validates our team’s vision and approach. We are excited about the future of Enbumyst in Esperion’s hands and its ability to intervene in the patient setting to treat worsening heart failure at home.”
James Udelson, chief of cardiology at Tufts Medical Center, said:
“Oedema and congestion remain the most burdensome and persistent symptoms for patients living with heart failure, often driving hospitalisations, impairing quality of life, and complicating day-to-day disease management. As a clinician who cares for these patients, it is challenging when they call in with worsening symptoms, as current oral diuretic options can be limited by delayed onset or absorption challenges. The availability of an FDA-approved intranasal diuretic like Enbumyst represents an important therapeutic advance. Its novel intranasal delivery route offers the potential for more flexible, rapid, and patient-friendly fluid management that can be done at home, precisely the kind of innovation we need to better support patients across the spectrum of cardiovascular and renal disease, and hopefully avoid the need for hospitalisation.”
Jefferies LLC served as exclusive financial adviser to Esperion and PJT Partners served as exclusive financial adviser to Corstasis. Gibson, Dunn and Crutcher LLP acted as legal advisers to Esperion and Arnold and Porter Kaye Scholer LLP as legal adviser to Corstasis.
