In addition, and more specific to the sector, any bull market for the sector will come to an end if or when high profile drugs start to fail Phase III clinical trials or the Food and Drug Administration turns down a high profile drug that everyone was certain would be approved.

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Normally, such tests would be only the earliest stages of getting a drug approved, and most medicines that pass these hurdles eventually fail in late-stage clinical trials.

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But most medicines in clinical trials are likely to fail.

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