Allakos Inc. announced it has initiated a randomized, double-blind, placebo-controlled Phase 2 clinical trial of subcutaneous (SC) lirentelimab in adult patients with moderate-to-severe atopic dermatitis. The company also announced plans to initiate two randomized, double-blind, placebo-controlled trials of SC lirentelimab in patients with chronic spontaneous urticaria (middle of 2022) and in moderate-to-severe, uncontrolled asthma patients with and without an eosinophilic phenotype (Q4 2022). Atopic dermatitis, chronic spontaneous urticaria and asthma are complex, chronic inflammatory diseases believed to be driven by activated eosinophils and mast cells. Atopic dermatitis is a chronic pruritic inflammatory condition that is characterized by dry, red, itchy patches of skin. Atopic dermatitis affects approximately 16.5 million (7.3%) adults in the United States (US), of which approximately 6.6 million (40%) have moderate-to-severe disease1. The Phase 2 study in atopic dermatitis is a 16-week, multicentered, randomized, double-blind, placebo-controlled trial that will enroll approximately 240 adult patients with moderate-to-severe disease who are inadequately controlled by topical treatments. Patients will be randomized 1:1:1 to receive four monthly subcutaneous doses of either: (a) lirentelimab 450 mg, (b) lirentelimab 150 mg, or (c) placebo. The primary endpoint will be the proportion of patients who achieve an Investigator Global Assessment (IGA) score of 0 or 1 with >2-point improvement at week 16. Chronic spontaneous urticaria is an often-debilitating skin condition characterized by frequent and unpredictable eruption of hives, severe itching and swelling. The disease affects up to 3.5 million patients in the U.S., of which half are refractory to standard-of-care antihistamines2. The planned Phase 2/3 study in chronic spontaneous urticaria will be a multicentered, randomized, double-blind, placebo-controlled study in patients who are na?ve to omalizumab and refractory to antihistamines. The primary end point of the trial will be the reduction of itch-severity score (ISS7). Asthma is a chronic inflammatory disease of the lungs that leads to narrowing and swelling of the airways, making it difficult to breath. Moderate-to-severe, uncontrolled asthma affects approximately 1 million adults in the U.S., of which 50% have an eosinophilic phenotype and 50% patients have a non-eosinophilic phenotype. The planned Phase 2 study in moderate-to-severe, uncontrolled asthma patients with and without an eosinophilic phenotype will be a multicentered, randomized, double-blind, placebo-controlled study. The primary end point of the trial will be the reduction of annualized asthma exacerbation rate.