shares of ptc therapeutics inc ptct were down 101 in trading on wednesday morning the day after the company said enrollment in a phase 2 clinical trial for its huntingtons disease treatment candidate has been paused ptc told investors on tuesday night that the food and drug administration had requested additional information about the study the company said there were no adverse events reported at trials in the us and in other sites being conducted in other countries ptcs stock is up 143 this year while the broader sp 500 spx is down 219