DEERFIELD, Ill. (December 30, 2011)--Walgreen CEO Greg Wasson says chances are slim to none that the drugstore operator will reach an agreement with pharmacy benefits manager Express Scripts before their current contract ends Saturday.

But Walgreen says it is taking several steps to help patients covered by an Express Scripts pharmacy network to continue to use Walgreen locations after the agreement ends.

It expects to keep more than 120 Express Scripts clients, including employers and health plans.

Express Scripts pays Walgreen and other drugstore operators to fill prescriptions.

The companies have said since June that they were preparing to stop business once their three-year contract ends this year.

Walgreen said it would rather give up the revenue it gets from Express Scripts than continue filling unprofitable prescriptions.