By Bhanvi Satija and Mariam Sunny

(Reuters) -Novartis has agreed to buy Regulus Therapeutics ( RGLS ) for up to $1.7 billion, giving the Swiss drugmaker access to an experimental drug to treat a life-threatening kidney disease.

Under the deal terms, Novartis will pay $7 per share in cash upfront, or about $800 million, and another $7 per share to Regulus shareholders if the lead drug candidate, farabursen, gets regulatory approval, the California-based biotech said on Wednesday.

The offer represents a premium of about 108% to the stock's last closing price. Shares of Regulus more than doubled to $7.8.

The deal, expected to bolster Novartis' lineup of kidney disease drugs in development, will also give the company access to Regulus' proprietary platform to develop treatments targeting a type of genetic material called microRNAs.

Regulus' drug, farabursen, is expected to enter a late-stage study this year to test it for the treatment of autosomal dominant polycystic kidney disease, which causes fluid-filled cysts in the organ.

The deal is a "sensible bolt-on" for Novartis, said Barclays analyst Emily Field. Farabursen is a potential improvement over poorly tolerated standard-of-care therapy, tolvaptan, Field said.

Otsuka Pharmaceutical's tolvaptan is the only treatment approved by the U.S. Food and Drug Administration in the country for the condition, but it carries the risk of potentially fatal liver injury.

Novartis has recently received U.S. approvals for its drugs Fabhalta and Vanrafia for the treatment of different types of kidney disorders. It had bought Chinook Therapeutics for $3.5 billion in 2023 for its candidate to treat a rare kidney disease.

Its agreement with Regulus comes when policy and regulatory changes for the healthcare sector in the U.S. have been stalling large lifescience deals in what was initially expected to be a stellar year for mergers and acquisitions.

Novartis said on Tuesday it expects adjusted earnings to grow by "a low double-digit" percentage in 2025.