A Swiss official has been allowed to visited him once.
But Swiss officials say they later developed misgivings about the project.
One Swiss official said there was some room for compromise between the two sides.
Swiss officials anticipate a 5 percent increase in American visitors this year.
Swiss officials refused to disclose the names of the other three companies.
Swiss officials said yesterday that they would not make it public.
Swiss officials, he said, had "come to an understanding that something needs to be done."
Swiss officials said they found him to be in satisfactory health.
But Swiss officials emphasize that their country's participation will be limited.
Swiss officials say they are setting a new course on soft drugs - simply because the traditional one is not working.