 Shares of Ardelyx Inc. ARDX, -3.17 rocketed 75.4 on heavy volume toward a 16-month high in premarket trading Thursday, after an advisory panel of the U.S. Food and Drug Administration voted that benefits of the biopharmaceutical companys treatment for chronic kidney disease CKD on dialysis, XPHOZAH, outweigh the risks. Trading volume was 11.7 million shares ahead of the open, compared with the full-day average of 4.3 million shares. 