Firstly don't think that this will not help primary progressives.
I'm primary progressive and it helped me a lot.
Professor Zamboni found that the 10 primary progressives in his study, after initial improvement returned to baseline after 18 mths. They stopped progressing.
10 subjects is statistically insignificant, certainly not large enough to infer it won't help us.
This is a scary time for you but be positive as there is a (and I'm gonna have to use the C word) CURE!