An $18 buyout would price in at about $1.3 billion (when you account for all of the outstanding warrants). Not bad for a company valued at just $60 million a couple months ago. Also, Merck would save a lot of milestones... nearly half of the purchase price. However, once the OS numbers come in, all bets are off, and the price of a takeover could be much higher. This is why I think Merck may want to move sooner rather than later, at least capture a majority stake this spring. Remember half of the US market is still dangling out there.