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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.

The compound is primarily intended for the treatment of eosinophilic esophagitis (EoE), an inflammatory disease of the esophagus. The disease is also known as “allergic esophagitis” and means that the patient has great difficulty swallowing. To date, no drugs with the same mechanism of action have been developed for EoE and there is a high unmet medical need.

Aqilion’s Phase 1 clinical trial of AQ280, ARIA-1, will include 64 healthy volunteers and so far (end of Q3 2022) just over half of the participants have been recruited. The purpose is to investigate possible side effects and how the body breaks down and gets rid of the substance. ARIA-1 is being conducted as a dose escalation study, which means that the trial begins with a very low dose, after which the dose is gradually increased. The primary objective is to establish the safety and tolerability of AQ280. The study is following its schedule and Aqilion expects a final report in Q2/Q3 2023. The company then intend to apply for drug testing prior to a Phase 2a clinical study in EoE 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.