U.S. private equity firm Gurnet Point Capital Ltd. is acquiring Corium International Inc. for up to $504 million.

Under the definitive agreement, Gurnet Point — which invests primarily in the healthcare and life sciences sectors, and is backed by Swiss billionaire Ernesto Bertarelli — will pay $12.50 per share in cash for all of Corium's outstanding common shares upon deal closing. The PE firm will also pay 50 cents per share if the U.S. Food and Drug Administration grants approval to Corplex donepezil, Corium's lead product candidate to treat Alzheimer's disease, before March 31, 2020.

Corplex donepezil is a proprietary once-weekly transdermal patch for delivery of the most commonly prescribed treatment for all stages of Alzheimer's disease. The product has met the criteria for bioequivalence to Pfizer Inc.'s Aricept using primary pharmacokinetic goals previously established with the FDA.

The transaction "provides Corium with the financial and other resources needed to bring Corplex Donepezil through regulatory approval and commercialization," Corium President and CEO Peter Staple said.

Essex Woodlands Management Inc., Corium's largest shareholder, has entered into a support agreement to tender its shares in the transaction.

Corium, a commercial-stage biopharmaceutical company, expects to close the deal by 2018-end, after which the company will offer to repurchase all of its $120 million in convertible notes.

Following deal completion, Corium will become private and will cease trading on the Nasdaq Global Select Market. The company plans to maintain operations in its Menlo Park, Calif. headquarters and in Grand Rapids, Mich.

Gurnet Point "will support the Corium team and its strategy for creating additional novel products like Corplex donepezil," Managing Partner Chris Viehbacher said. "We will also be providing a significant financial investment to quickly expand Corium's operations and establish a commercial organization that can effectively bring these products to the market upon approval, including the addition of a dedicated sales force that is scaled appropriately for the products and their prescribers."

Guggenheim Securities serves as financial adviser to Corium, while Fenwick & West LLP is legal adviser. Weil Gotshal & Manges LLP acts as legal adviser to Gurnet Point.