Aristea launched in December 2018 as an AstraZeneca spin-out. The company dove into the biopharma space with $15 million in Series A backing to rehome molecules to develop novel treatments against severe inflammatory conditions. "Our aim here is to take molecules that have been discarded by big pharma for a variety of reasons, or from other biotechs who have taken them through preclinical development but are not equipped to take them into clinical," Mackay told BioSpace in a January 2022 interview. Novo Holdings, the private limited liability company under the Novo Nordisk group, backed the startup. Aristea gained exclusive global rights to RIST4721, its lead asset, from AstraZeneca. The candidate is an antagonist of the CXCR2 protein and was set to enter Phase II assessments in palmoplantar pustulosis when the company launched. The company completed enrollment into this study in October 2019.