WASHINGTON – The Walgreen pharmacy chain will begin filling prescriptions from customers in the Express Scripts network again starting in September under a new multiyear contract between the companies.

The agreement comes after a series of disputes between Walgreen and Express Scripts that ended with the discontinuation of the contract between the drugstore operator and the pharmacy benefit manager last year.

Since January, Walgreen has not filled prescriptions for Express Scripts, saying the company was not paying enough in drug dispensing fees. Its sales have slumped since the split.