PTC Therapeutics Inc (PTCT)

Shares of PTC Therapeutics (PTCT) dropped by 22.71% from $23.95 to $18.51 in the trading on Friday, October 27, 2023. The reason why PTCT stock down is due to a change in its regulatory submission plan. Originally, PTC Therapeutics had planned to seek FDA approval in the fourth quarter of 2023. However, the FDA now requires a 26-week nonclinical mouse study before authorization. As a result, PTC Therapeutics has altered its submission pathway from 505(b)(2) to 505(b)(1), which necessitates the collection of additional data. This regulatory change has impacted investor sentiment, leading to the significant drop in PTCT's stock price.

European regulators rejected full approval for PTC Therapeutics' Duchenne muscular dystrophy treatment, Translarna, causing a 29.8% drop in PTC stock. The decision came due to insufficient evidence, and PTC plans to seek reexamination from the European Commission.

https://www.investors.com/news/technology/ptc-stock-crashes-after-european-regulators-reject-its-muscular-dystrophy-drug/?src=A00220