Matthew Klein, M.D., M.S., F.A.C.S., current Chief Operating Officer, has been named the company's CEO and will join the Board of Directors. The transition is effective immediately. Dr. Peltz will serve as a Senior Consultant to the Company and join its Scientific Advisory Board following his retirement.

Prior to joining PTC in 2019, Dr. Klein was CEO and Chief Medical Officer at BioElectron Technology Corporation, a biotechnology company focused on the development of redox-active small molecules for mitochondrial disease and related disorders of oxidative stress. PTC acquired BioElectron's assets in 2019. As CEO and CMO of BioElectron, Dr. Klein led the restructuring of the company with successful implementation of new strategic and operational plans and led the development of two novel small molecules targeting CNS diseases from discovery to early and late clinical development stages.

In addition, he oversaw the formation of an oncology platform that yielded several novel preclinical compounds with novel approaches to targeting cancer.Dr. Klein joined PTC as Global Head of Gene & Mitochondrial Therapies and then assumed the role of Chief Development Officer prior to promotion to COO in January 2022. At PTC, he has overseen the Company's broad development pipeline now with five ongoing registration-directed clinical trials and headed the efforts in achieving EMA approval for Upstaza, the first ever gene therapy directly administered to the brain.Dr. Klein holds a Bachelor of Arts in history, and graduated summa cum laude and phi beta kappa from the University of Pennsylvania. He received his Doctor of Medicine degree with honors from Yale University.

In addition, Dr. Klein holds a Masters of Epidemiology degree from the University of Washington. Prior to leading BioElectron, he was the Auth- Washington Research Foundation Endowed Chair for Restorative Burn Surgery at the University of Washington. He has authored or co-authored over 100 peer-reviewed scientific publications and has served on the Research Advisory Board of the Shriners Hospitals for Children for over 15 years.