Ardelyx Inc. shares soared more than 60% in after-hours trading Wednesday, after the company reported positive results for a study of a proposed drug. Ardelyx said a second Phase 3 study of tenapanor, a drug targeting irritable bowel syndrome with constipation, reached its primary endpoint and all secondary endpoints, and was well-tolerated by patients. "These results are a game-changer for patients with IBS-C, their treating physicians and for Ardelyx as a company," Ardelyx Chief Executive Mike Raab said in . The same drug previously . Ardelyx shares topped $8.50 in late trading after closing at $5.40.