Phase 2a randomised, double-blind, placebo-controlled study to evaluate the efficacy and safety of londamocitinib (AZD4604) two times per day for 12 weeks in adult patients with moderate-to-severe asthma uncontrolled on medium-high-dose ICS-LABA.

introductionAsthma is a heterogeneous condition and affected individuals show variable responses to available medications. An unmet need exists for add-on therapies that target novel molecular pathways, before patients escalate to biologics. Janus kinase 1 (JAK1) is implicated in multiple inflammatory cytokine pathways critical for the pathogenesis of asthma. Londamocitinib (AZD4604) is a highly specific, inhaled, JAK1 inhibitor with high potency to block multiple JAK1-dependent signalling pathways. AJAX is a phase 2a, randomised, double-blind, partially decentralised placebo-controlled study assessing the efficacy, safety and pharmacokinetics (PK) of londamocitinib in adults with moderate-to-severe asthma uncontrolled on medium-to-high-dose inhaled corticosteroid/long-acting β METHODS AND ANALYSIS: The primary endpoint is time to first CompEx Asthma event. Secondary endpoints include change from baseline in prebronchodilator forced expiratory volume in 1 s, chronic airways assessment test, six-item asthma control questionnaire, daily asthma symptom score, and morning and evening peak expiratory flow at weeks 4 and 12. In addition, assessment of the effect of londamocitinib on airway inflammation as measured by the fractional exhaled nitric oxide test; cough severity assessment; and the PK of londamocitinib in all participants after 4 and 12 weeks will also be evaluated. ETHICS AND DISSEMINATION: The study has received ethical approval from the appropriate ethic committee and will be conducted in accordance with the Declaration of Helsinki, Good Clinical Practice guidelines, and all applicable regulatory requirements. All participants will provide written informed consent prior to enrolment, with procedures in place to ensure comprehension and voluntary participation. Findings will be disseminated through peer‑reviewed publications and/or presentations at scientific conferences. Summary results will be posted on the trial registry and shared with participants and relevant patient groups in lay summaries.