Of the total amount, Allergan will pay $460m upon closing of the deal, while $100m will be paid by 2016.
The deal will also include potential research and development (R&D) success-based and sales-threshold milestone payments.
Allergan’s portfolio will now include Naurex’s lead development product rapastinel (GLYX-13), a once-weekly intravenous Phase III-ready molecule that showed efficacy in multiple Phase II clinical studies in depression.
Naurex is involved in developing transformative therapies for challenging disorders of the central nervous system (CNS).
Allergan CEO and president Brent Saunders said: "We expect Naurex will enhance Allergan’s mental health portfolio and build on our strategy to lead in this important therapeutic area.
"Naurex’s unique pipeline comprises compounds that utilise a new mechanism to target areas of significant unmet medical need in major depressive disorder (MDD), including severe and/or treatment-resistant depression."
Naurex’s discovery platform includes N-methyl-D-aspartate (NMDA) receptor modulators, including subtype-selective molecules that can treat a wide range of psychiatric and neurologic disorders.
Rapastinel is a new NMDA receptor modulator that is being developed as an adjunctive treatment for difficult-to-treat major depressive disorder.
The deal will see addition of another next-generation drug candidate into Allergan’s portfolio, NRX-1074, an orally bioavailable drug candidate that is in Phase I studies.
The transaction, subject to customary closing conditions, is expected to complete by the end of this year.