Jeff founded and built Spark Therapeutics into the world’s first fully integrated, commercial gene therapy company, serving as co-founder and CEO from 2013 to 2022. Under Jeff’s leadership, Spark developed and launched LUXTURNA® for a rare blinding disorder, the first FDA-approved gene therapy for a genetic disease in the United States, spearheading the creation of novel reimbursement models to ensure patient access to genetic medicines. As CEO, Jeff shepherded multiple gene therapies into the clinic for patients with conditions ranging from inherited retinal diseases to rare bleeding and neuromuscular disorders. While at Spark, Jeff raised $1 billion and established major partnerships with Pfizer and Novartis. Jeff’s successful orchestration of Spark’s $4.8 billion sale to Roche in 2019 marked a 100-fold increase in the company’s market value over six years and delivered financial returns of $750 million to Spark’s non-traditional founding investor, The Children's Hospital of Philadelphia (CHOP). At the time of his departure, Spark had grown to 850 employees and was named #5 in Science magazine’s rankings of top employers across the biopharmaceutical industry.Jeff currently serves on the boards of several start-up companies including Chroma Medicine and Prime Medicine as well as on the boards of multiple non-profit organizations, including CHOP, Life Science Cares and The Rendell Center for Civics and Civic Engagement. In 2022, Jeff and his wife founded the Marrazzo Family Foundation to foster creativity in Philadelphia youth.Jeff holds two bachelor’s degrees in systems science and engineering and in economics from the University of Pennsylvania as well as two master’s degrees in business and public administration from Wharton and Harvard University, a dual-degree program which he founded.