The deal includes a drug approved in the U.S. and the EU for systemic mastocytosis, a rare immunology disease, as well as an early-stage immunology pipeline, the companies said.

Blueprint, based in Cambridge, has an approved drug called Ayvakit that treats a rare immunological condition.

Sanofi announced that it will buy pharma company Blueprint Medicines for $129 per share, making the deal worth more than $9 billion. Blueprint specializes in systemic mastocytosis and other diseases driven by KIT, a receptor on mast cells.