I think if there is an offer it'll have to be a multiple of what...

I think if there is an offer it'll have to be a multiple of what they would have returned during the same period. Eg if you held for 10 years then you might expect it to be 2 X (1+28%)^10 = $23.61/ share. Ie 28% return/growth each year is still lower than the $20bn USD valuation I put on the shares recently at approx $33 AUD/ share .
so $6bn USD is only only a 10x increase on current price :. A price of $11.50 not much of a change for all those who did purchase when. It hit $9.99 years ago.
cash flow will not be an issue for the company if it gets approval, so dilution or selling will be of lesser interest.
remember silviu wants these products on the market, not put in a closet so big pharma can continue to have you on the hook ongoing for their drugs. What meso offers if potential cures or maybe getting a single back does every 3 years! Doesn't help steroids!
Not financial advice.