Vertex to buy Seattle company

Vertex Pharmaceuticals announced Wednesday that it would acquire a Seattle biotechnology company focused on developing innovative immunotherapies for $4.9 billion in cash. The Boston-based drug company said it was buying Alpine Immune Sciences for $65 a share. The deal, which is the largest acquisition in Vertex’s history, was unanimously approved by the boards of both firms and is expected to close later this quarter. Alpine’s lead drug candidate, called povetacicept, has shown potential for treating IgA nephropathy, or IgAN, a serious progressive autoimmune disease of the kidney that can lead to end-stage renal disease and affects 130,000 people in the United States. There are no approved drugs that treat the underlying cause. Because of the way the experimental drug works, povetacicept could also help patients with other serious autoimmune diseases of the kidney, according to the companies. Vertex, based in Boston’s Seaport District, is best known for four game-changing and pricey drugs for cystic fibrosis, a rare genetic disorder, that have won approval since 2012. But with the success of those medicines, the company has been seeking to diversify its drug pipeline. In December, Vertex and Swiss-based CRISPR Therapeutics won approval of the first drug to use CRISPR-Cas9 gene-editing to treat an illness, sickle cell disease. Called Casgevy, the one-time treatment for the inherited blood disorder costs $2.2 million per patient. About a month later, Vertex said an experimental painkiller it developed was as effective treating acute postsurgical pain in clinical trials as a commonly prescribed pain reliever that contained an opioid — without the risk of addiction. — JONATHAN SALTZMAN