Not sure what you mean about another Part B extension? The participants all have an extension that will provide a full 12 month period.
I understand that it has already been indicated that further extensions may be introduced as more results become available, if positive.
Obviously one of the big concerns the participants have is that is this drug is successful/beneficial they don't want to be taken off it. The researchers don't want this either and it makes sense to continue the core group to monitor longer term results.
How would we know that no participants had requested a further extension? All subjects requested a 26 week extension, and I think only a few would be at or near 52 weeks at this point.