Shares of Threshold Pharmaceuticals (NASDAQ:THLD) jumped up 15% today, bizarrely upon news that its competitor Celgene (NASDAQ:CELG) announced a set of successful phase 3 results. In this video, Motley Fool health-care analyst David Williamson tells investors what was behind this counterintuitive pop, and why it could be an excellent indicator for some of Threshold's own trials.

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