With the announced cuts coming before the end of the year, “hundreds” are set to have a less than Merry Christmas.

It’s likely that the employees affected have been told or will be shortly, but so far details are not forthcoming. Dierdre Connelly, who heads North American operations, has stated that the drug-maker is looking to cut costs by $1.6 billion over the next three years with the bulk of this cutting to be reflected in its 2016 balance sheet. The company first announced this cost cutting in October of this year.

GlaxoSmithKline To Cut Hundreds Of U.S. Jobs Before Year's End

GlaxoSmithKline’s employees to begin to hear details today

A spokesperson for the company recently told the Wall Street Journal that the cost cutting “is to improve performance by taking unnecessary complexity out of our operations and establish a smaller, more focused, organization, operating at lower costs that support our future portfolio. Each business unit is currently deciding how to respond to this challenge.” When asked for further details, she declined stating, “When we do have proposals, we will first share those with our employees.”

The cuts are not a terrific surprise given the company’s third quarter sales results which fell 11% in GlaxoSmithKline plc (ADR) (NYSE:GSK) (LON:GSK)’s biggest market (The U.S.). The drop was primarily due to poor sales of its best-selling product Advair.

Reorganization of GlaxoSmithKline’s R&D facilities

Of the 99,000 employees that GlaxoSmithKline plc (ADR) (NYSE:GSK) (LON:GSK) has working for it worldwide, 17,000 of them are based in the United States and its believed that the bulk of the cuts will occur at the company’s North Carolina R&D site as the company looks to streamline its research and development given “market changes, evolving customer needs and the overall U.S. business environment.” GSX , in a letter of intent, spoke of its desire to shift around 450 of its R&D staff in Research Triangle Park, near Durham, N.C. to Parexel International and create a dedicated GSK business unit within PAREXEL. That shift will “provide a variety of clinical development services and be largely based in the RTP area,” according to a release from GSK.

In addition to R&D restructuring and reorganization, sales and marketing employees are also on the chopping block though to a considerably lesser extent.

GlaxoSmithKline plc (ADR) (NYSE:GSK) (LON:GSK) will pare its Research Triangle Park R&D team and consolidate its R&D around its sites in the Philadelphia region and at Stevenage, U.K. It’s believed that some North Carolina workers will be offered a chance to relocated to one of these sites.