Jeri, in Canada the length of the patent used to be shorter (17 years) than that of the US (20 years), but was changed with the passage of Bill C-91 to comply with US laws. The multinational drug companies still managed to make huge profits in this country despite Canadian generic drug manufacturing.

Before the WTO, individual countries could determine how long they would grant patent protection on drugs in their own "soverign" nations. Here is an article on how it has affected Canada and the implication on generic drugs.

The Doctors Without Borders site also provides some background and there is a link on the Oxfam site under Issues that also summarizes the problem.