Merck, the international pharmaceutical giant, announced mass layoffs that will hit its sales personnel based in suburban Philadelphia.

About 500 people affiliated with Merck’s offices in Lansdale and Upper Gwynedd will lose their jobs in permanent reductions in force, the company said in a required letter it filed Wednesday with the Pennsylvania Department of Labor and Industry.

“The roles being eliminated are located across all states; but for administrative purposes, the jobs are associated with Merck’s U.S. headquarters in Upper Gwynedd,” said a company spokesperson. “Employees whose jobs are impacted by these changes can apply to other open positions at Merck. Impacted employees who are not placed in a role will be offered a comprehensive separation package.”

Earlier this month, Johnson & Johnson said it planned to eliminate 297 employees at its Wayne facility, in a similar letter sent to the Department of Labor.

Merck said the changes "are part of ongoing company-wide efforts to sharpen Merck’s focus on innovative research and development.”

The layoffs will be effective Jan. 3. The positions are not union-protected jobs.

The job cuts "will primarily affect certain field-based and office-based sales personnel within the company’s Human Health Division,” stated the letter, signed by Terri J. Lee, the vice president of state government affairs and policy. “The affected field-based sales personnel work out of their homes in various states [including Pennsylvania] throughout the United States.”

Merck considers its North Wales office in Upper Gwynedd to be the single site of employment for its field-based personnel.

“Significant layoffs at one of the area’s largest employers is terrible news for Lansdale and for our surrounding communities," said Lansdale Mayor Garry Herbert. “The high quality jobs that Merck has been able to offer at all of their facilities helped grow Lansdale into what it is today and it is a real detriment to our community that they are choosing to make this massive change to so many lives. Obviously, it is our hope that Merck is able to retain many of the area employees in other facilities putting those highly trained employees back to work as soon as possible for the sake of their families and their well-being.”

J&J’s filing said the jobs in Wayne had been cut because it had decided to “permanently discontinue the product line manufactured at that location.”

Company representatives for J&J did not immediately respond to requests for comment.