Mark Gergen served as CEO and Chairman of Poseida Therapeutics, a clinical-stage cell and gene therapy company developing treatments for cancer and rare diseases. He transitioned to Executive Chairman in January 2024 after six years of executive leadership.

Gergen joined Poseida in February 2018 as Chief Business Officer and CFO, bringing over 25 years of healthcare experience. He previously held senior leadership roles at Halozyme, Mirati Therapeutics, and Amylin Pharmaceuticals.

Gergen holds a J.D. from the University of Minnesota Law School and has extensive expertise in business development, strategy, and operations across biopharmaceuticals and medical devices. He has been a member of Poseida's Board of Directors since 2018.

Under Gergen's leadership, Poseida executed strategic partnerships with Roche (July 2022) and secured a $50 million investment from Astellas Pharma (August 2023). The company completed its IPO in July 2020, raising over $200 million in net proceeds.

Gergen led Poseida through major milestones including FDA clearance on four IND applications and dosing over 100 patients in clinical trials. In January 2025, Roche acquired Poseida for up to $1.5 billion, validating the company's allogeneic CAR-T technology platform.