Stocks Tumble On Tetraphase, Flexion Failures; Surge On Akebia Win

Antibiotic developer Tetraphase Pharmaceuticals Inc. and arthritis pain drug maker Flexion Therapeutics Inc. were battered in after-hours trading on Sept. 8 after the companies said their lead drug candidates failed to reach statistical significance in late-stage clinical trials, but investors rewarded Akebia Therapeutics Inc. for positive mid-stage results for its anemia drug after the stock market closed.