Walgreens is suing Theranos for $140 million in federal court in Delaware, the Wall Street Journal reports.
The pharmacy giant is suing its former blood-testing partner for an alleged breach of contract. The complaint has been sealed, so the details remain unknown.
Theranos told the Journal that it is "disappointed" that Walgreens had decided to file the lawsuit. It added:
Over the years, Walgreens [has] consistently failed to meet its commitments to Theranos. Through its mishandling of our partnership and now this lawsuit, Walgreens has caused Theranos and its investors significant harm. We will respond vigorously to Walgreens' unfounded allegations, and will seek to hold Walgreens responsible for the damage it has caused to Theranos and its investors.