Cell line development (CLD) is a critical first step towards drug development. Agenus has established a cutting-edge in-house CLD facility that assures quality and flexibility with production schedules, while reducing timelines and costs. Our CLD facility in Cambridge, UK, (Agenus UK) has established an efficient system starting with high throughput screening and selection of clones and ending with the development of robust and reproducible cell lines with commercial grade yields. Agenus UK can efficiently deliver high-yielding, stable monoclonal cell lines to our in-house GMP manufacturing facility (Agenus West) for commercial scale production within ~ 4 months. Through close collaboration and parallel workflows, Agenus UK and Agenus West facilitate faster INDs and seamless supply of clinical product, which is essential for clinical and, ultimately, commercial success. Current efforts by our team at Agenus UK to automate the CLD process is expected to shrink timelines even further.