This is a reasonable offer any BP or major investor(s). The buyer gets 100 million shares which will most likely be trading above $10 immediately; the stake holder can sell those shares back to get back the $1 billion, and still owns 20% without any risk.
If I had several billion$ sitting around; I would take on this investment. Very little risk; I get my money back and I own 20% of future profits.
With $1 billion, mnkd has a very strong chance of successful launch and profitability.