Aad van de Leur is a highly experienced biotech professional with over 40 years of expertise in CMC development, biotechnological process development, and GMP manufacturing. He has in-depth knowledge of cell culture, downstream processing, purification, analytical development, validation, and the associated quality and regulatory aspects. Aad combines strong technical expertise with operational and strategic leadership in both clinical and commercial environments.
From 2013 to early 2025, Aad served as Chief Operating Officer (COO) at Byondis (formerly Synthon Biopharmaceuticals) in Nijmegen. In this role, he was responsible for all biopharmaceutical operational activities, including process development from cell line to drug product, manufacturing and supply of IMPs and future commercial material, with a strong focus on monoclonal antibodies (mAbs) and Antibody Drug Conjugates (ADCs).
Since July 2025, Aad has been active as an independent consultant, leveraging his broad CMC and operational experience to support biotech and biopharma organizations.
Expertise and Services
• CMC development within biotech and biopharmaceuticals
• Biotechnological process development and validation
• Manufacturing and technology transfer (clinical and commercial)
• Cell culture and downstream processing
• Quality and regulatory aspects within CMC programs
• Operational and strategic management
Positions
• Chief of Staff – Batavia Biosciences (2025 – present)
• COO – Byondis (2013–2025)
• Vice President / Director Biopharmaceutical Development – Synthon (2009–2012)
• Senior Director Customer Project Management – Organon (2003–2008)
• Director / Assistant Director Downstream Processing R&D – Diosynth (1993–2003)
• Laboratory Technician – Diosynth & Organon (1985–1993)
Professional Experience (selection)
Since July 2025, Aad has been working as Chief of Staff at Batavia Biosciences, where he supports the CEO on organizational matters, the development of viral vector vaccines, and the qualification of a new large-scale production facility. Prior to joining Batavia, he worked at Byondis (formerly Synthon Biopharmaceuticals) from January 2009 onward, initially in senior development and management roles and from 2013 as COO. He led end-to-end biopharmaceutical CMC activities, from early process development to clinical and commercial manufacturing and supply.
Before that, Aad spent more than 23 years in various biotech departments at Diosynth and Organon/Schering-Plough. He started in cell culture development, where he was involved in the development, optimization, and troubleshooting of cell culture processes using, among others, hollow fiber bioreactors, cell factories, (fed-)batch fermentation, and perfusion systems up to a scale of 100 liters.
He subsequently spent more than 10 years responsible for purification process development, optimization, viral clearance studies, troubleshooting, production of glycosylated proteins, and cleaning validation. In his final phase at Organon, Aad led complex technology transfer projects for approximately five years, including cell culture, purification, and analytical transfers for both internal projects and external partners.
Throughout his career, Aad has been involved in multiple regulatory filings and interactions with EMA, FDA, and Japanese authorities.
Education
• MSc Chemistry – Utrecht University
• Ing. HNWO – Dr. Struycken Institute
Skills
CMC development • Biotech process development • Manufacturing & tech transfer • Cell culture • Downstream processing • Purification • Quality & regulatory oversight • Operations management
LinkedIn
https://www.linkedin.com/in/aad-van-de-leur-4728307/