With a number of its drug patents ready to expire and widespread general changes in how the industry operates, Pfizer, the largest drug company in the world, announced Tuesday that it was instituting $4 billion in cost cuts.

This was necessary, it was said, because the company’s earnings will fall this year. Other concerns include worries over pricing, regulation, safety issues, and increasing government regulation of how drug companies conduct their operations.

Cost-cutting measures will include increasing the efficiency of its research program, reorganization of sales operations to take into consideration the greater impact of drug sales to the government in the U.S. through the Medicare program for the elderly, and a reorganization and streamlining of its worldwide operations.

Not many layoffs are expected, with the downsizing of employment rolls to be taken care of through attrition. Pfizer also said it will put more emphasis on preventative health activities in cooperation with large employers and the Medicare program.