The Spartacus project aims to rethink the concept of treating spondyloarthritis (SpA), a form of chronic arthritis. First-in-line disease management typically starts with non-steroidal anti-inflammatory drugs (NSAIDs) and/or conventional specific immune modulators defined as synthetic disease modifying anti-rheumatic drugs (DMARDs). Refractory patients are treated with more expensive, second-in-line biologicals. An earlier study indicated that using more expensive biologicals, TNF inhibitors, as primary treatment option resulted in complete resolution of symptoms in 82% of patients with 50%  staying in drug free remission (CRESPA trial). These promising results with biologicals as first-in-line indicate that patients suffering from a chronic disease can be reverted to a drug-free state. This project aims to validate these earlier results in a window-of-opportunity trial and in a larger cohort. A large and complex clinical trial with different treatment arms was started, in which synovial biopsies were subjected to single-cell- and epigenetic profiling. The setup and logistics of the single-cell immuno-phenotyping of the synovial tissue samples were consolidated in parallel between the research partners, to unravel potential signatures for responders versus non-responders.