The drugmaker told employees the osteoporosis team will disintegrate at the end of the year, according to a source. That’s because the patent on Fosamax expires in February. The med has been a big seller for Merck for years, ringing up more than $3.1 billion in annual sales in each of the last three years. The move will affect about 250 people, mostly sales reps.

A Merck spokeswoman confirmed the move in this e-mail:

“As you are most likely aware, Merck’s marketing exclusivity for Fosamax will expire in the first quarter of 2008. Accordingly, Merck is eliminating 250 positions - primarily in the osteoporosis specialty sales force. Merck notified the impacted individuals now to allow ample time for them to pursue other opportunities, including those available within the company.”

Later, another note came over the transom, saying the drugmaker hopes to help the “vast majority” find new roles at Merck.