Full approval sooner.....In this link...
Frequently Asked Questions: Breakthrough Therapies | FDA Question no 16?
''Would a clinical trial for a drug that has been designated as a Breakthrough Therapy generally have to enroll fewer patients prior to approval?''
The answer seem to be yes.
If the answer is yes, it does seem that 75 patients with strong data could be enough to accelerate the full approval(unless my interpretation of the above link is wrong).