Look at this. Aboriginal health picked up on the PBT2 story...

Look at this. Aboriginal health picked up on the PBT2 story before Prana holders. Well done Prana for keeping your shareholders up to speed.
http://aboriginalhealth.net/health-news/antibiotic-resistant-bacteria-with-the-alzheimers-drug-fight/
It is almost funny. The only reason I can guess for this secrecy from holders and prospective investors, only, is to depress the price.  The pharmaceutical industry across the world, that is those more in position to go after the Patent or introduce competing drugs, were already widely informed. It looks like everybody in the industry across the world knew, so why keep it from Prana investors(owners). Maybe because it would have generated wider news coverage in the US. 
A simple announcement of fact about the PBT2 result may have boosted the price a little and attention could refocus on the high expectations of the PBT434 Parkinsonian program results coming soon.
This is from the 2018 ann report
[Also in thelast 12 months, a case has transitioned through the PCT International phase, being directed to a new use for PBT2that is not a neurodegenerative disease.] I guess that is “Method of treatingimmunoglobulin light chainamyloidosis”Filed: 1 July 2016

All the above is just opinion, because I know nothing about what is going on with PBT2. DYOR