Esperion to buy Corstasis for $75M upfront, adds FDA‑approved Enbumyst spray

Esperion Therapeutics said it will acquire privately held Corstasis Therapeutics for $75 million in cash upfront, up to $180 million in additional regulatory and commercial milestone payments and low double‑digit royalties on Enbumyst and follow‑on products. The deal, announced March 3, is expected to close in the second quarter of 2026 and is subject to customary conditions; one republished item noted a potential termination if the transaction is not completed by May 1, 2026.

The acquisition brings Enbumyst (bumetanide nasal spray), approved by the Food and Drug Administration in September 2025 for edema associated with congestive heart failure and edema tied to hepatic and renal disease in adults, into Esperion’s portfolio. Company materials called Enbumyst "the first and only FDA‑approved nasal spray loop diuretic," and positioned the product as a differentiated, self‑administered outpatient therapy that could bridge gaps between oral and intravenous diuretics and ease pressure on inpatient care.

Esperion said it will acquire all outstanding stock of Corstasis through a subsidiary, after which Corstasis will become a wholly owned Esperion unit. The company plans to fund the transaction through existing credit facilities and by monetizing its Japanese royalties with funds managed by Athyrium Capital Management and HealthCare Royalty. The press release announcing the deal was distributed via GlobeNewswire and republished on platforms including Yahoo Finance, where it carried a paid press release notice.

The transaction is framed as strategic diversification for Esperion, which built its business on LDL cholesterol therapies such as NEXLETOL and NEXLIZET. Esperion said adding Enbumyst will allow it to leverage its cardiovascular commercial infrastructure and help drive "double‑digit revenue growth" as it expands beyond cholesterol management. Company materials cited an estimated 6.7 million U.S. adults with congestive heart failure and described a potential U.S. market opportunity exceeding $4 billion.

From a market standpoint, the deal signals consolidation among smaller commercial biotechs and a willingness by specialty drugmakers to buy late‑stage or recently approved niche products rather than develop them in house. Financing the purchase through credit and royalty monetization reflects a broader trend of companies monetizing noncore cash flows to fund bolt‑on acquisitions. For investors, the key variables to watch will be the pace of Enbumyst uptake, the size and timing of milestone payments that could total up to $180 million, and the eventual royalty percentage within the described "low double‑digit" range, which the companies did not specify.

Several important details were not disclosed in the announcement. The companies provided no sales figures or launch performance metrics for Enbumyst since its September 2025 approval, did not define the milestones that trigger the contingent payments, and did not specify the exact royalty rate or its duration. Esperion also did not quantify expected GAAP accounting impacts from the purchase price allocation, or outline integration plans for Corstasis personnel and commercial operations.

Regulators beyond customary closing approvals were not identified as prerequisites. With the closing timeline stretching into Q2 and a possible May 1 termination deadline reported by a syndicate that republished the release, stakeholders will be watching for the filing of an 8‑K or similar disclosures that could provide the missing financial and operational detail.