Traders shorting May calls and puts could be in for a nasty 20 dollar surprise move in the stock. Conference data for DNDN will be released this Thursday. From Minyanville: "While some companies have already released details of what their presentations will entail, the full abstracts will be available on the ASCO website on May 20. Biotech and pharma stocks tend to see a good increase prior to the conference and could jump on any significant results that are released at the conference -- so now is the time to put your money down."
The latest story in Google Finance also says DNDN could be taken over. It's just not a good time to be short options in this particular stock.