April 10 (Reuters) - Vertex Pharmaceuticals will acquire therapy developer Alpine Immune Sciences for $65 per share, or about $4.9 billion in cash, the companies said on Wednesday.

With the acquisition, Vertex will add Alpine's portfolio of protein-based immunotherapies to treat autoimmune and inflammatory diseases.

The transaction, approved by Vertex and Alpine's boards, is expected to close in the second quarter of 2024.

Shares of Alpine were up 20% in extended trading. (Reporting by Christy Santhosh in Bengaluru; Editing by Shilpi Majumdar)