DEERFIELD, Ill. — Walgreens mitigated projected repercussions out of the chain's withdrawal from the Express Scripts pharmacy network come January, as the Walgreens/Express Scripts failed negotiations again dominated the pharmacy's quarterly analyst call Tuesday morning. All told, Express Scripts represents $5.3 billion in revenue to Walgreens, but the Chicago-based pharmacy is working toward retaining the prescription business from several employers and payers, "consistent with their contractual obligations," executives emphasized.