TPI ASM8 reduces eosinophil progenitors in sputum after allergen challenge

Summary Background TPI ASM8 contains two modified phosphorothioate antisense oligonucleotides (AON), one targeting the common beta chain (βc) of the IL‐3/IL‐5/GM‐CSF receptors and the other targeting the chemokine receptor CCR3. Inhalation of TPI ASM8 significantly improves lung function and sputum eosinophilia after allergen inhalation challenge in asthmatics. Objective This study assessed whether TPI ASM8 reduces airway levels of haemopoietic progenitor cells. Methods This open‐label study was conducted in 14 stable, allergic mild asthmatic subjects with early‐ and late‐phase allergen‐induced bronchoconstriction. Subjects underwent allergen challenges after 4‐day treatment with placebo, 4 mg b.i.d. and 8 mg o.d. of TPI ASM8. Sputum was induced before, 7 and 24 h after allergen challenges for progenitor measurements. Treatments were separated by 2–3 weeks. Results TPI ASM8 reduced allergen‐induced sputum eosinophils, and the early and late asthmatic responses (P