Mallinckrodt Pharmaceuticals and Endo Inc. plan to merge and create a $6.7 billion company in a move that will cut costs and broaden access to patients and new treatments.

Mallinckrodt and Endo are set to merge in a cash-and-stock deal valued at $6.7 billion, with the drug makers set to list shares of the new firm on the New York Stock Exchange. Shareholders in Endo, which makes sterile injectables and generic pharmaceuticals,