Esperion Therapeutics to Acquire Corstasis, Expanding Its Cardiovascular Franchise with Enbumyst

Esperion Therapeutics has entered into a definitive agreement to acquire Corstasis Therapeutics, a privately held biopharmaceutical company. The acquisition focuses on the integration of Enbumyst™ (bumetanide nasal spray), the first and only FDA-approved intranasal loop diuretic, into Esperion’s existing cardiovascular portfolio.¹

The transaction— consisting of an upfront cash payment of $75million and provisions for Corstasis shareholders to receive up to $180 million in additional payments contingent upon the attainment of specific regulatory and commercial milestones— is a core component of Esperion's long-term commercial strategy to address significant unmet needs in the outpatient management of fluid overload.¹

What Market Opportunity Does Enbumyst Address for Esperion?

Enbumyst targets a substantial U.S. market opportunity estimated to exceed $4 billion.¹ The primary target population includes the approximately 6.7 million American adults living with congestive heart failure (CHF), in which edema—swelling caused by excess fluid in body tissues—is a defining clinical feature.² Beyond CHF, the product is indicated for edema associated with hepatic and renal disease, including nephrotic syndrome, providing a pathway for Esperion to expand its footprint in metabolic and renal care.¹

“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,” stated Sheldon Koenig, president and chief executive officer of Esperion.¹

From a commercialization standpoint, Esperion plans to leverage its established cardiovascular commercial infrastructure to integrate Enbumyst into existing sales channels. The product is expected to be available across multiple healthcare settings, including specialist offices, outpatient heart failure clinics, and integrated delivery networks. Additionally, Corstasis is advancing a sub-cutaneous pipeline, including a multidose pen injector, which offers further potential for market expansion and long-term revenue diversification.¹

How Does the Nasal Delivery Platform Differentiate Enbumyst in the Diuretic Space?

Enbumyst, which received FDA approval on September 12, 2025, represents a significant shift in the delivery of loop diuretics. Traditionally, patients with worsening edema rely on oral loop diuretics, which can be limited by delayed onset or poor gastrointestinal absorption. When oral therapies fail, patients often require intravenous (IV) diuretics, which typically necessitate inpatient hospitalization or specialized infusion settings.²

Enbumyst fills this therapeutic gap by offering a self-administered outpatient therapy that provides rapid absorption through the nasal mucosa. In a randomized, controlled trial of healthy volunteers, bumetanide nasal spray demonstrated bioequivalence to oral and IV formulations regarding its effect on diuresis (urine production) and natriuresis (sodium excretion).¹ By providing a bridge between oral and IV treatments, Enbumyst allows for earlier intervention at home, which clinicians suggest could potentially reduce the economic burden of heart failure-related hospitalizations.

What are the Financial and Strategic Terms of the Transaction?

Esperion intends to fund the acquisition through its existing credit facilities and the monetization of Japanese royalties with funds managed by Athyrium Capital Management and HealthCare Royalty.¹ The transaction is expected to close in the second quarter of 2026, pending customary closing conditions. Strategically, the move advances "Vision 2040," Esperion’s roadmap for delivering differentiated cardiovascular innovations to high-need patient populations while driving sustained double-digit revenue growth.¹

“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,” Koenig said.¹

How Will Healthcare Professionals Optimize the Clinical and Commercial Rollout of Enbumyst?

The commercial success of Enbumyst depends on appropriate patient selection and adherence to safety protocols. As a loop diuretic, it functions by acting on the kidneys to increase urine flow. Each spray delivers 0.5 mg of bumetanide, and the standard adult dose is one spray in one nostril.³

Pharmacists are expected to play a critical role in ensuring patient access and providing essential counseling on the proper administration of the nasal spray. Because Enbumyst is a one-time-use device that must not be tested or primed before application, clear patient education is paramount to avoid dose wasting.³

By managing clinical complexities and drug interactions, healthcare providers can help optimize the utilization of Enbumyst in the outpatient setting, supporting Esperion’s objective to establish the product as a new standard of care for edema management.

References

1. Esperion Therapeutics. Esperion Therapeutics and Corstasis Therapeutics Announce Esperion’s Definitive Agreement to Acquire Corstasis, Expanding Its Cardiovascular Franchise with Enbumyst™ (bumetanide nasal spray). Press release. Published March 3, 2026. https://www.esperion.com/news-releases/news-release-details/esperion-therapeutics-and-corstasis-therapeutics-announce
2. Halpern L. FDA Approves Bumetanide Nasal Spray for Edema With Heart Failure, Hepatic and Renal Disease. Pharmacy Times. Published September 16, 2025. Updated September 18, 2025. https://www.pharmacytimes.com/view/fda-approves-bumetanide-nasal-spray-for-edema-with-heart-failure-hepatic-and-renal-disease?utm_source=chatgpt.com
3. Mayo Clinic. Bumetanide (nasal route) - Side effects & dosage. Updated January 31, 2026. https://www.mayoclinic.org/drugs-supplements/bumetanide-nasal-route/description/drg-80008509?utm_source=chatgpt.com