We're pretty much down the road on risk now. Pona will rule this company's future, rida 2nd or third in line.
Your approach depends on answers to three questions 1) do you think pona will be successful 2) will Pona alone take the price well beyond where a successful SUCCEED trial would, i.e. greater than $8 3) Can you wait 18 months without needing the money invested (risk tolerance)
If your answers are 1) yes, 2) yes 3) yes, the put it all in now. Your price is $3.70, your upside is say $8.70 or better, your profit $5. If you wait, your price could be either $7, or $2.00 PIII fail). If you wait, and PIII is good and then you buy, your upside is 1.70 or better. If you buy now PIII fails, you forego a dollar (or so)but still make more than double by not waiting. This also overcomes the logic that at $2, you could purchased twice as much stock than at current levels.
Time nearly totally dissolves the risk of SUCCEED, as over time, Pona will drive the value well beyond it. And then there is upside from endo. This time approach nearly 100% nullifies the buy now risk.
If you aren't 3 yeses, then follow the 1/2 in approach.
WARNING: Know yourself. You'd better be very risk tolerant and and really believe in Pona to go in now.