Francisco Leon

Founder and CEO of Tolerance Bio, a biotech start-up focused on improving healthspan by restoring and preserving the function of the thymus, a key regulator of immune tolerance. https://www.tolerancebio.com/

Co-founder of Paulex Bio, a clinical-stage biotech company working towards a world without diabetes. Paulex is developing preventative and regenerative therapies for Type-1 and Type-2 Diabetes. https://paulexbio.com/

Co-Founder of Avalor Therapeutics, a biotech start-up developing breakthrough precision medicine for chronic inflammation. Avalor is initially focused on disease modification in osteoarthritis. https://avalortx.com/

Board Director at Lapix Therapeutics, clinical-stage biopharma company developing novel, orally bioavailable immune system restoration therapies for autoimmune diseases and oncology. https://lapix.com/

Praetorian Bio is a biotech startup in stealth mode, developing a revolutionary preventative approach for oral health.

Vaxdyn is a biotechnology company located in Seville, Spain, developing a vaccine platform for antibiotic-resistant bacteria, such as Klebsiella, Acinetobacter and Pseudomonas. Our goal is to decrease the impact on public health of infections caused by drug-resistant pathogens. https://vaxdyn.com/

Company ideation and personal consultancy firm.

Glutenostics commercialized rapid gluten detection assays (Gluten Detect Stool and Gluten Detect Urine) to help people avoiding gluten to be more compliant with their diets. As of Nov 2025, operations continue under Biomedal, which commercializes Gluten Detect directly (https://glutendetect.es/en/) and via Amazon.com: - URINE: https://www.amazon.com/Gluten-Detect-Kit-Tests-Gluten-Free/dp/B0FV3F359C/ref=sr_1_4?crid=3CIIHXC2WPB5F&dib=eyJ2IjoiMSJ9.UzbDpoGD_AVa7Ikugn7oUr3inxxcOt_STh9Y3UclCz3KYH-GbZZSc74adoX_oAZW3VdzEiVTQTi5IfeAyoLPODdy_qjLNOrVu2rT-36cyBFcbhceZzeKEowoTdHMGd93vA5G4qsfUjQi9VEyDAxB8jFnxHUo4R-P4fM60zcdPg4XTLlIfSj5vNRpS5rRylz6.OgEP1s37pM6G1GQJTe0Evy6sS0lID6nxFkQ8WcF9I2o&dib_tag=se&keywords=glutendetect&qid=1773599424&sprefix=glutendetect%2Caps%2C133&sr=8-4&th=1 - STOOL: https://www.amazon.com/Gluten-Detect-Kit-Tests-Gluten-Free/dp/B0FT3KFCHY/ref=pd_sbs_d_sccl_2_1/131-2626319-3673309?pd_rd_w=qq1YU&content-id=amzn1.sym.aa738fbd-ad05-4d11-aae2-04b598db6305&pf_rd_p=aa738fbd-ad05-4d11-aae2-04b598db6305&pf_rd_r=M52PVXEC49DZPMG4C3D2&pd_rd_wg=nAD6z&pd_rd_r=f230fb8f-958b-4e1c-b9d4-f62d75b179a7&pd_rd_i=B0FT3KFCHY&psc=1

After the acquisition, I help transition and advance the Provention Bio pipeline in Sanofi, focusing on Tzield (PROTECT completion and regulatory activities, intellectual property development, life cycle).

Co-Founder, Chief Scientific Officer, former Board Director (2018-2019), former Chairman of the Scientific Advisory Board (2017). Provention Bio was acquired by Sanofi in April 2023. Provention was a clinical-stage biopharmaceutical company dedicated to sourcing, developing and commercializing novel therapeutics and cutting edge solutions to intercept and prevent immune-mediated disease. Our founding mission was to reduce the high-morbidity/mortality and escalating costs of autoimmune and inflammatory diseases, such as type 1 diabetes, celiac disease, Crohn’s disease, ulcerative colitis, lupus and emerging viruses. Our pioneering approach was to “predict” and “pre-empt” immune-mediated disease – to identify at-risk patients and intervene before the targeted disease begins, re-appears or progresses. At Provention, I had the privilege of leading scientific aspects of our programs, with focus on the advancement of teplizumab/TZIELD®, and responsibility for our celiac (PRV-015, anti-IL-15), lupus/gene therapy (PRV-3279, CD32B/CD79B bi-specific) and coxsackie vaccine (PRV-101) programs. I functionally managed Translational Medicine, Biomarkers, Intellectual Property and Pharmacokinetic teams, and supported Business Development, Investor Relations, Corporate Communications and Commercial.

DPT. OF BIOCHEMISTRY, UAM (mentor: Dr. A. Sillero), and DPT. OF CLINICAL IMMUNOLOGY, HOSPITAL RAMÓN Y CAJAL (thesis director: Dr. G. Roy). Thesis: "New immunological approaches in the diagnosis and pathogenesis of Celiac Disease and other enteropathies" (“Summa Cum Laude”).Courses at the National Center for Biotechnology (CNB) and the Molecular Biology Center (CBM, Cantoblanco Campus, Madrid, 1998-2000).

- UNIVERSITY OF TROMSO, NORWAY: Invited Researcher, Dpt. of Immunology, Institute for Medical Biology [Aug 1993 Sep 1994]. - UNIVERSITY OF OXFORD, ENGLAND: Elective student, Dpt. of Clinical Immunology [Jul Aug 1994]. - UNIVERSITY OF ODENSE, DENMARK: Erasmus Program Student, Medical School and Language School [Aug Dec 1992]. - UNIVERSITY OF UTRECHT, HOLLAND: Summer Course "Medicine and National Health Systems" [Jul 1990].