Our Mission
Immune-mediated diseases represent a significant unmet medical challenge: cancer, autoimmunity, transplant rejection, infections, immune deficiencies, and allergy.
Abnormalities in immune tolerance underpin all these disease areas. The thymus is the essential organ for establishing and maintaining immune tolerance, yet it involutes over time, leading to increased susceptibility to immune diseases.
Our accomplished team is pioneering a novel, multi-platform approach to control immune tolerance at will - by restoring, preserving, and manipulating the function of the thymus.
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Francisco Leon is the Founder and CEO of Tolerance Bio. He is also the Co-founder and Chairman of Paulex Bio, focused on prevention and treatment of diabetes.
Francisco is a clinical and basic immunologist with a long career in academia (NIH), biopharma (BMS, MedImmune/AZ, Janssen/JNJ) and as an entrepreneur – as CEO, CMO and CSO of several companies.
He has led or participated in the development of 6 drugs which reached the market, most recently teplizumab (TZIELD®) for the delay or prevention of the onset of clinical type 1 diabetes, and has co-founded two biotech companies acquired by Pharma: Celimmune, acquired by Amgen in 2017, and Provention Bio, acquired by Sanofi in 2023.
Founder and CEO
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Holger Russ, PhD, is a pioneer in stem-cell derived thymic and beta cell generation. He is an Associate Professor in the Department of Pharmacology and Therapeutics at the Diabetes Institute of the University of Florida. He is also an Honorary Senior Research Fellow at the Institute of Metabolism & Systems Research at the University of Birmingham in the UK.
Dr Russ’s research focuses on the generation of functional human thymic and pancreatic islets from pluripotent stem cells. He has made significant contributions to the field of regenerative medicine, and is a co-inventor on eight patents in this area.
Scientific Co-founder
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Justin Vogel is a seasoned financial leader with close to two decades of experience in the biotech industry. As a pivotal member of various teams, he has successfully raised over $1.3 billion in equity and debt transactions to fuel R&D, clinical development, and commercial operations.
With a track record of building and directing financial operations for four biotech public companies, including Provention Bio and Iveric Bio, Justin brings deep technical accounting knowledge and expertise to the table.
Noteworthy achievements include supporting product launches like TZIELD and spearheading business development and finance efforts for in-licensed programs from industry giants like Amgen and BMS. As a Certified Public Accountant, he is dedicated to driving financial excellence and innovation within the biotech sector.
Chief Financial Officer
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Phil Ball, PhD, has over 20 years of international biopharma experience in business development, alliance management, product development, and global health policy.
Prior to Tolerance Bio, Phil was VP of Alliance Management and Business Development for Provention Bio until its acquisition by Sanofi. Earlier in his career, he held roles of increasing responsibility at Allergan, Actavis, Watson Pharmaceuticals, and Eden Biodesign.
Phil received his BSc in biochemistry from the University of Manchester and PhD in biochemistry from the University of Liverpool.
Chief Business Officer
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Yeh-Chuin Poh, PhD, is SVP and Head of Tech Ops, with extensive experience in cell and gene therapy and involvement in multiple IND approvals. He was Senior Director of Cell Process Development and CMC Lead at Beam Therapeutics, where he established manufacturing processes for cell therapies. Previously, he led the development of stem cell-derived pancreatic beta-cells at Semma Therapeutics (acquired by Vertex) and co-founded Absolute Nano (acquired by United Science), focused on nanomaterials synthesis. Poh earned his BSE in mechanical engineering from the University of Michigan and his MS and PhD in mechanobiology from the University of Illinois Urbana-Champaign, completing postdoctoral research at MIT.
SVP, Head of Tech Ops
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Paul Dunford, VP of Translational Sciences, has over 25 years of expertise in preclinical and clinical immunology and pharmacology. In his senior roles at Roche, Janssen, and Provention Bio/Sanofi, he has successfully led in vitro and in vivo pharmacology groups, advancing numerous novel therapeutics to first-in-human (FIH) studies.
Paul has led the development of novel biomarkers for rapid go/no-go clinical studies in rheumatoid arthritis, lupus, and IBD. His extensive experience spans leading preclinical and clinical project teams for both small and large molecules. At Janssen, he was the clinical science lead for a Stelara registrational PK study and was the global project head for a Phase 2 autoimmune asset at Sanofi. Additionally, he recently led non-clinical and biomarker teams in support of the BLA submission and FDA approval of teplizumab (TZIELD®). Paul has authored 31 peer-reviewed papers and is a co-inventor on seven drug development patents.
VP, Translational Science
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Christian Blount, MBA, PMP, Senior Director of Program Management, has a decade of program management experience in biologics and cell and gene therapy. He possesses broad knowledge across therapeutic areas including hematology, immuno-oncology, inflammation & immunology, cardiovascular & metabolic, neurology, and emergent diseases.
Christian has deep expertise in CMC strategy, program development, and risk management. At Beam Therapeutics, he co-led cross-functional teams developing CMC strategies for BEAM-101 and BEAM-201. He also established program management fundamentals across functional groups. At Regeneron Pharmaceuticals, he led clinical programs from IND-enabling to late-stage clinical and validation, and managed lifecycle strategies for commercialized products like LIBTAYO® and KEVZARA® in collaboration with Sanofi. Christian's leadership ensures collaborative and efficient program execution.
Senior Director, Program Management
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Linda Arterburn, PhD, is a biotechnology executive with over 30 years of experience in R&D and regulatory affairs. She has led discovery, preclinical, translational, and clinical research, most recently as Vice President of Regulatory Affairs at Sanofi and Provention Bio. There, she oversaw European regulatory strategies for type 1 diabetes immunotherapies and regulatory development for pipeline products in celiac disease and virology. Previously, she held leadership roles at Medifast and biopharma companies focused on HIV prevention and nutrition. Linda holds a PhD in Pharmacology and Molecular Sciences from Johns Hopkins University School of Medicine and a BS in Biochemistry from the University of Wisconsin-Madison.
Regulatory Lead
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Jacquelyn (Jackie) Brown, PhD, is an immunologist with deep expertise in research, medical affairs, and scientific communications. She contributed to type 1 diabetes research at JDRF before joining Provention Bio, where she supported the approval and launch of TZIELD. After Sanofi’s acquisition of Provention, she served as U.S. Publications Lead for type 1 diabetes. Most recently, she was Associate Director of Scientific & Medical Affairs at Orna Therapeutics. Jackie earned her PhD in Immunology from the University of Pennsylvania, studying developmental immunology and lymphocyte cytotoxicity, and completed a fellowship at Memorial Sloan Kettering Cancer Center.
Immunology Research Lead
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Carina Meyer, PhD, is a bioanalytical scientist specializing in cell therapy development. At HebeCell Corp., she led assay development for stem cell-derived NK cell therapies, and supported the transition from R&D to GMP manufacturing. An expert in flow cytometry, qPCR, and cytotoxicity assays, she established robust quality control processes. Carina earned her PhD in Neuroimmunology from Memorial Sloan Kettering Cancer Center and the University of Freiburg, studying microglia mutations in neurodegeneration. She holds a BSc and MSc in Molecular Biotechnology from the University of Heidelberg, Germany.
iPSc Bioanalytical Lead