up 43% with large volume on nasdaq

Progen Industries (ASX:PGL) is trading on ASX at a large discount to the price on the US market.
In the past few weeks the volume traded in USA has increased and last night more than 1 mil. shares traded (big vol. for this stock) on NASDAQ where PGLAF closed @ US$0.83 = A$1.27. One PGLAF = one PGL.
Can't explain why PGL is trading at such a discount in OZ.
Today (11 June) Progen will be having presentations for shareholders in Brisbane and Sydney. 12 June in Melbourne.
Prof. John Zalcberg, a non-executive director, will give a presentation on PI-88 clinical development program with clinical interpretation.
My guess is that biotech investors in US are aware of the content of this presentation.