The DFA Discussion, page-11

Having conducted searches, there is no evidence of the company having made any representations that if the Opthea trials were unsuccessful, then the capital advanced would not have to be repaid. This is confirmed by the fact that the DFA investors took a Charge over all the Assets and Undertakings of Optea, that Optea would be required to pay up to 4 times the loan or $680 million dollars.

The DFA investors were not interested in running a lottery, which is what it would have been. They accepted the risk, but determined that it was covered by the assets of the company in the even that the trials were unsuuccessful.