By Julian Pecquet - 12/05/11 09:10 PM EST
"We understand that a combined entity has the potential to control 60 percent of mail order and 50 percent of the specialty market," the letter says. "With that type of market concentration, it is important that your agency works to see that access to health care is not limited."
Opposition to the proposed deal cuts across party lines. The latest letter brings to at least 23 the number of lawmakers who have raised concerns with the merger.