Chinook Therapeutics (KDNY) shares skyrocketed on Monday after Novartis (NVS) agreed to buy the biopharmaceutical company for up to $3.5 billion.

The deal values ​​Chinook stock at at least $40 per share, a 67% premium to the company’s closing price on Friday. Chinook shareholders will receive $40 per share in cash at closing, with up to an additional $4 per share upon achievement of certain regulatory milestones. Novartis said the transaction would be in the form of a merger between Chinook and a newly formed Novartis subsidiary.

Novartis noted that Chinook has two highly valuable late-stage drugs in development for rare and severe chronic kidney disease. It explained that the purchase is fully in line with its strategy to focus on innovative medicines and will “significantly expand its kidney portfolio and complement the existing pipeline”.

Chinook CEO Eric Dobmeier added that through the merger, “Novartis can leverage its considerable resources to further pursue the broader development and commercialization” of Chinook’s treatment.

The companies said they expect to close the deal in the second half of this year.

Shares of Chinook Therapeutics were up more than 56% as of 11:30 a.m. ET, their highest this year. Novartis shares fell 1%.