"With Zytiga approved and MDV3100 and Alpharadin going to be filed for approval soon (and both available already under compassionate-use programs), Exelixis will have a tough time enrolling patients in Study 307. If we assume the trial starts now, I don't expect the company to have data until the first half of 2015 at the earliest, and that assumes a lightning-fast enrollment pace and an early halt for efficacy. How likely is it that the cabo trial can be halted early for efficacy? Not so much because cabo has yet to show any survival benefit to date. The drug is being studied at a new, lower dose and at every turn, it seems inferior to the competition. On pain, Alpharadin and Zytiga are better; on survival MDV3100, Provenge, Alpharadin and Zytiga win; and on quality of life, Alpharadin and Amgen's Xgeva win.

"I see two possible outcomes: Exelixis is forced to resize the trial, i.e. add more patients, which means more cost and more time; or Exelixis moves forward with the current trial size, setting up a very high-risk event that is more likely to fail."

Thank you, Bio-investor X.

Porter M. writes, "I want you on the record with a prediction for the Arena Pharmaceuticals panel. With all your negativity, you shouldn't be able to weasel out of being wrong when the panel votes to approve."

Not a problem. I predict Thursday's FDA advisory panel vote will be negative, meaning the recommendation will be for FDA to reject lorcaserin a second time. I don't have a guess on the actual vote count. I'm sure some of the experts will vote in lorcaserin's favor, just not enough. Recall, the first FDA advisory panel in September 2010 voted 9-5 against lorcaserin.

That's my prediction, on the record. If I'm wrong, you won't have to wait long for me acknowledge my error publicly. I will be live-blogging the lorcaserin FDA advisory panel, so please tune in. And don't worry, Arena will get fair treatment from me on the live blog.

Haley W. asks, "Isn't FDA adding many obesity experts to the Arena panel a good thing? Why would these people not want a new weight-loss drug to be approved?"

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