The insurer Cigna will spend about $52 billion to acquire the nation’s biggest pharmacy benefit manager, Express Scripts, the latest in a string of proposed tie-ups as health care’s bill payers attempt to get a grip on rising costs.
Including $15 billion in debt, the proposed $67 billion acquisition follows a deal announced late last year in which the drugstore chain CVS Corp. said it will spend around $69 billion on the insurer Aetna Inc.
Insurers and pharmacy benefit managers — which run drug plans for insurers and employer-based plans — have struggled to corral spiraling costs and the industry that was jolted by the Affordable Care Act, which reshaped the individual insurance market and expanded the state- and federally funded Medicaid program.

