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Regulus represents an entirely new compound, a next-generation selective JAK1 inhibitor previously developed under the name LEO 142397, now AQ280. The Phase 1 ready anti-inflammatory program was acquired from LEO Pharma in December 2021. Aqilion  started a Phase 1 safety study in healthy volunteers in August 2022, to be followed by a Phase 2a study in patients.

Selectivity holds the potential to optimize efficacy and to minimize some side effects. AQ280 shows selectivity over JAK2 should leave erythropoiesis and myelopoiesis pathways minimally affected which is expected to reduce potential class related side effects.

Drugs with a similar mechanism of action have shown clinical efficacy in autoimmune and inflammatory diseases. Aqilion will initially investigate AQ280 as a potential therapy for eosinophilic esophagitis (EoE), an inflammatory disease of the esophagus. To date, no drugs with the same mechanism of action have been developed for EoE and there is a high unmet medical need.