The court found that the winning bid included language that improperly broke from the bid specifications and gave OptumRx "a clear competitive advantage."
The ruling complicates pharmaceutical benefits for more than 800,000 New Jersey public workers and the $1.6 billion employees and state and local governments are projected to save over the contract's three-year run.
A spokeswoman for Express Scripts, which brought the suit, told NJ Advance Media it is "encouraged by the decision and looks forward to the opportunity to participate in the re-bidding process."
The state is self-insured for prescription drug benefits but outsources administration of the program to a pharmacy benefit manager that negotiates prices and rebates with drug manufacturers. They get paid in a couple ways, including a management fee and by collecting a share of those rebates.