(Reuters) -Vertex Pharmaceuticals will buy Alpine Immune Sciences (NASDAQ:) for about $4.9 billion in cash, gaining access to the biotech firm’s treatment for an autoimmune disease of the kidney, the companies said on Wednesday.

The deal values each share of Alpine at $65, representing a premium of about 67% to the stock’s close on Tuesday, a day before Bloomberg News reported that the company was considering options after attracting takeover interest.

Shares of Alpine were up 36% in extended trading, while Vertex (NASDAQ:) Pharma was down about 1%.

The gene therapy developer will now have access to Alpine’s povetacicept, which is in mid-stage development for the treatment of IgA nephropathy (IgAN) and will be evaluated in a late-stage trial in the second half of 2024.

Povetacicept works by targeting types of proteins called BAFF and APRIL, which together contribute to the development of multiple autoimmune and antibody diseases.

IgAN, which occurs when clumps of antibodies are deposited in the kidneys, affects about 130,000 people in the United States, according to the companies.

Vertex currently has approval from the U.S. Food and Drug Administration for the treatments of cystic fibrosis — a rare genetic disorder that affects mostly the lungs — and two types of blood disorders, namely sickle cell disease and transfusion-dependent beta thalassemia.

Alpine said in a filing it may be required to pay Vertex a fee of $173 million on termination of the deal, which is approved by the boards of both companies and expected to close in the second quarter of 2024.