On September 15, 2023, PTC announced that the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency issued a negative opinion of its drug Translarna, for the treatment of nonsense mutation Duchenne muscular dystrophy. The CHMP concluded that Translarna’s benefit-risk balance was negative and denied conversion of the conditional marketing authorization to full marketing authorization, in addition to the renewal of the existing conditional authorization. Analysts noted that they were surprised by the CHMP’s decision to deny renewal of Translarna’s marketing authorizations.

Following this news, PTC’s stock price fell by $11.13 per share, or approximately 30% to close at $26.26 per share.