RA is an inflammatory autoimmune disease that causes pain, swelling and stiffness in the joints. It can also cause fatigue, and the underlying inflammation may affect other body systems. Treating RA quickly after diagnosis and as early as possible after symptom start has been shown to have a significant impact in its further development. With the discovery of the preclinical phase of the disease, the idea of treating people who are at-risk with the aim of preventing RA is very attractive. However, to do this requires carrying out clinical trials to assess the safety and efficacy of treatments in the ‘pre-RA’ phase. Some initial trials in this area have looked at very different populations—with variation in eligibility criteria, biomarkers, interventions, and outcomes. This makes it hard to interpret and compare the evidence as it accumulates.