There is nothing illegitimate about investing through the Cayman's or any other tax haven. Most multinational US companies trading on the big boards have subsidiaries located in tax havens; that is a fact (read some OECD literature/statistics).
CELG would not be involved with a fraud; a $15M investment is not large for them, but it is large enough that their professionals did their DD before investing.
Read my board and you will see I am the first to call 95% of OTC companies frauds. I don't know how the PPS will move with this ticker (no one does), but the company is not a fraud.
It is important to distinguish between P&D's and legitimate high-risk tickers; each should be traded in a completely different manner IMO.
Every trades a winner, and every trades a loser, and the most you can hope for is to die in your sleep.