I really like the following question:

I'm not sure the end of the biotech bull market is near. The stamina exemplified in the chart is incredible: ^NBI Chart ^NBI data by YCharts

Of course, not all biotech and drugs stocks increase in value forever. FDA rejections and failed clinical trials tend to have a depressing effect on share price. With that in mind, here are five stocks which I predict will end 2013 lower than where they trade today:

1. Vanda Pharmaceuticals ( VNDA): I expect the tasimelteon FDA panel on Nov. 14 to end badly for Vanda.

2. Coronado BioSciences ( CNDO): I don't believe in the "hygiene hypothesis" so I predict negative results from the CNDO-201 phase II study in Crohn's disease. The risk: Phase II study results can be fungible, meaning flaws are more easily swept under the rug.

3. Oncolytics Biotech ( ONCY): In my opinion, management has worked hard to delay and hide as much Reolysin data as possible because the experimental cancer-killing virus is incapable of killing cancer at all. The ugly truth about Reolysin can't be hidden forever, however, so I expect the upcoming data from a study in head-and-neck cancer patients will be a total bust.

4. Amarin ( AMRN): The stock is beaten up already so the short is less compelling, but I expect the Oct. 16 FDA panel to recommend against approving Vascepa for the so-called "Anchor" patient population. Instead, the panel will tell FDA to wait two years for definitive cardiovascular outcomes data from the ongoing REDUCE-IT study.

5. Vivus ( VVUS) and Arena Pharmaceuticals ( ARNA): Two stocks but they're related. Their respective obesity drug launches are flailing. Script growth is totally unimpressive and the stocks, while down sharply already, are still over-valued.

Samuel R. asks:

There have been confusing reports on NewLink Genetics (NLNK) and the interim analysis of the pancreatic cancer trial. Can you call the company to see what is really happening. Your help would be most appreciated.

It's pretty simple. NewLink CEO Charles Link spoke at a couple of health care investment conferences this week and pushed back the timing on the interim analysis of the algenpantucel-L (a cancer vaccine) phase III pancreatic cancer study.

The trigger for the interim analysis is 222 death events in the study. The company first expected the analysis to take place in the middle of the year, then it was pushed back to the second half of the year. When asked for an update at the investor conferences this week, Link said the company is now unsure if the 222nd death in the study will occur this year at all.

NewLink spokeswoman Gina Nugent confirmed Link's new guidance for me:

"Adam, What Dr. Link said during the Baird and Stifel conferences (webcast available) was that the trigger event for the first of three planned interval analysis, which will occur when 222 death events are recorded, has not yet occurred and that management is not sure that this first trigger event will occur before the end of 2013."

What does this delay in the interim analysis mean?

NewLink is encouraged, arguing pancreatic patients in the study's control arm are unlikely to be living longer than expected. Therefore, patients being treated with algenpantucel-L might be living longer. The study is blinded so there is no way to know definitively what's going on until the interim analysis is conducted.

Skeptics (and yes, I'm in this group) believe the more likely explanation is NewLink messed up the survival assumptions used to design and power the study. All patients -- not just those treated with algenpantucel-L -- are living longer than NewLink expected. We've seen ample examples of phase III studies of cancer drugs in which delays in reporting survival endpoints ended badly -- GlaxoSmithKline (Mage-A3) Vical ( VICL) (Allovectin) and Oncoythreon ( ONTY) (Stimuvax), most recently. NewLink is no different. This delay in the interim analysis increases the risk that the phase III study ultimately fails, not the other way around.

With that said, I also believe a lot of time is being wasted by fixating on the outcome of the algenpantucel interim analysis. Even under the most ideal circumstances, the odds that the cancer vaccine works so effectively to stop the study early for efficacy are very small. The most likely outcome is that NewLink continues to enroll patients and we wait for more definitive results next year.

-- Reported by Adam Feuerstein in Boston.

Follow Adam Feuerstein on Twitter.
Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.

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