Eli Lilly (LLY) has agreed to acquire AtaiBeckley (ATAI) for $2.8 billion in cash plus potential milestone payments of up to $1.0 billion, the companies said Thursday.

Under the deal, Eli Lilly will pay $6.75 per share of AtaiBeckley plus up to $2.50 per share as a contingent value right on achievement of development and regulatory milestones, including the initiation of phase 3 trials and regulatory approvals of its mental health therapies, the companies said.

AtaiBeckley develops therapies for treatment-resistant depression and other serious mental health conditions.

The deal, already approved by the boards of both companies, is not subject to any financing condition and is expected to close in Q3, subject to approval by AtaiBeckley shareholders and regulatory approvals, the companies said.

Shares of AtaiBeckley were up more than 30% in recent premarket trading.