Vertex Pharmaceuticals Inc.’s bad news from a phase II pain study and separately on the regulatory front caused shares (NASDAQ:VRTX) to close Aug. 5 at $393.83, down $78.44, or 16%. Vertex rolled out top-line results from the phase II dose-ranging study to test the safety and efficacy of its NaV1.8 pain signal inhibitor, VX-993, in tackling acute pain after bunionectomy.