UnitedHealth UK signed a three-year deal to help NHS Northamptonshire commission NHS services in 2008.
But a spokesman for the PCT confirmed 'both parties' agreed to end the deal this month.
John Parkes, chief executive of NHS Northamptonshire, said: 'The NHS landscape has changed. We've had successes, including improvements in the use of data and pathways for chronic disease patients.'
The deal was agreed under Labour's framework for the procurement of external commissioning support, which approved 14 companies to help PCTs deliver services.
Firms are now hoping to work with GP consortia as they take on commissioning from 2013.