Asthma is a heterogeneous chronic airway disease comprising of distinct phenotypes characterized by different immunopathophysiologic pathways, clinical features, disease severity, and response to treatment. The phenotypes of asthma include eosinophilic, neutrophilic, mixed cellularity, and paucigranulocytic asthma. Eosinophilic asthma is principally a T helper type 2 (Th2)-mediated airway disease. However, several other immune and structural cells secrete the cytokines implicated in the pathogenesis of eosinophilic asthma. Innate type 2 lymphoid cells, mast cells, basophils, and eosinophils secrete Th2 cytokines, such as interleukin-4 (IL-4), IL-13, and IL-5. Additionally, airway epithelial cells produce alarmin cytokines, including IL-25, IL-33, and thymic stromal lymphopoietin (TSLP). Alarmins are the key initiators of allergic inflammation at the sentinel mucosal surfaces. Innovative biotherapeutic research has led to the discovery of monoclonal antibodies which target and inhibit the immunopathological effects of the cytokines involved in the pathogenesis of eosinophilic asthma. Parenteral biologics targeting the inciting interleukins, include mepolizumab and reslizumab (anti-IL-5), benralizumab (anti-IL-5Rα), dupilumab (anti-4Rα), and tezelizumab (anti-TSLP). They have been shown to significantly reduce annualized exacerbation rates, improve asthma control, lung function, and quality of life. Currently, there are no pulmonary delivered aerosol biologics for topical treatment of asthma. CSJ117 is a potent neutralizing antibody Fab fragment against TSLP, formulated as a PulmoSol TM engineered powder, and is delivered to the lungs by a dry powder inhaler. Phase 2 placebo-controlled clinical trial evaluated the efficacy and safety of CSJ117. CSJ117 delivered as an inhaler attenuated the late asthmatic response (LAR), and the early asthmatic response (EAR) after allergen inhalation challenge (AIC) at day 84 of treatment. The maximum decrease in FVE1 from pre-AIC were significantly lower in the CSJ117 group compared to placebo (P = 029), during LAR. CSJ117 also significantly reduced fractional exhaled nitric oxide before AIC at day 83; and significantly reduced the allergen-induced increase in % sputum eosinophil count. Pulmonary delivery of biologics directly to the airway mucosal surface has several advantages over parenteral routes, particularly in treating airway diseases such as asthma. Inhaler delivered biologics, such as CSJ117 are innovative and attractive methods of future precision treatment of asthma, and other respiratory diseases.