Well for almost sure PBT434 has a better safety profile than...

Well for almost sure PBT434 has a better safety profile than DFP. Both can remove the labile(free) iron, which is thought to be the problem, but DFP removes it with a much stronger binding force, capable of removing iron from cell stores, and that can create problems.

DFP  Kb=10-36                 PBT434   Kb=10-10 

DFP even has a stronger zinc attraction than PBT2. 

For anyone interested have a look at page 14 of this Dr Stamler presentation to see the effect of DFP iron chelation on patients in a 6 month study.

http://pranabio.com/wp-content/uploads/2018/01/Prana-Biotechnology-JPM-investor-presentation_updated.pdf 

There is good reason to expect the current Fair Park II study will be successful, and that is good news for PBT434 IMO. DYOR