PTC study failure has minimal impact on thesis, says William Blair

William Blair analyst Sami Corwin keeps an Outperform rating on PTC Therapeutics after the MIT-E study of vatiquinone in patients with refractory mitochondrial epilepsy did not meet the primary endpoint of reduction in observable motor seizures. While we view the study’s inability to achieve its primary endpoint as unfortunate, the firm previously thought a 50% reduction in seizure frequency was a high bar to meet, the analyst tells investors in a research note. Furthermore, based on the small addressable population, the program was not a central part of the valuation thesis and its removal only reduced the stock’s net present value by $1.50 per share, says the firm. It continues to believe PTC’s phenylketonuria program remains undervalued.