By Raghav Mahobe and Nandhini Srinivasan Nov 18 (Reuters) – Provention Bio Inc (PRVB.O) has priced its diabetes drug teplizumab at $13,850 a vial, it said on Friday, a day after receiving U.S. approval and far higher than some analysts’ expectations. The company’s shares reversed course from premarket gains to trade down nearly 12% as the high pricing stoked fears...