There will have to be a Japanese trial for Japanese approval, that I know. The only possible exception would be if there was an ethnic Japanese cohort in the Australian trial, which I don't really expect.
Yes, eventually there will be U.S. trials and trials in other places around the world too. But since S.O.C. is so incredibly awful and we are really talking about an historic first here, there is no way to project how the FDA will handle this.
Missling, however, probably has a much better idea, and this information may have been shared with Biogen or another perspective partner under NDA.
We will know when we know, but personally I don't believe 2017 is out of the question.