Mark D. Rosen, PhD has been vice president and head of chemistry at Nine Square Therapeutics since January 2021. He is responsible for medicinal and computational chemistry, drug metabolism, screening and other drug discovery activities. Before joining Nine Square, Dr. Rosen was the inaugural head of chemistry at Verge Genomics, where he built and led the team that discovered Verge’s PIKfyve inhibitor portfolio, culminating in successful completion of Phase 1 clinical trials for amyotrophic lateral sclerosis in June 2023. Dr. Rosen has also held leadership roles at Akebia Therapeutics, Regulus Therapeutics and Johnson & Johnson (Janssen), where he conducted drug discovery research for more than 12 years. He earned his bachelor’s degree from the University of California, San Diego and completed a PhD in organic chemistry at the University of California, Irvine.