Blockade of thymic stromal lymphopoietin receptor (TSLPR) reduces allergic inflammation in a cynomolgus monkey model of asthma

TSLP pathway blockade is a potential strategy for asthma treatment, as TSLP modulates cytokine production by mast cells and regulates the activation of dendritic cells (DCs), which prime the differentiation of nave T cells into inflammatory Th2 cells. To assess the effect of TSLPR blockade on the development of allergic inflammation and bronchoconstriction in Cynomolgus monkeys after Ascaris suum allergen challenge. Antibodies against human TSLPR were generated and confirmed to be cross-reactive to cynomolgus. Animals were dosed weekly with either vehicle (n=8) or TSLPR HuMAb (n=8) for 6 weeks and their responses to A.Suum challenge at baseline, week 2 and week 6 were assessed. Antibody-treated animals showed reduced bronchoalveolar lavage (BAL) eosinophil counts (p=0.04), reduced lung resistance (RL) area under the curve (p=0.04), and reduced IL-13 cytokine levels in BAL fluid (p=0.03) in response to challenge at 6 weeks compared to vehicle-treated animals. To understand the molecular changes underlying these differences, BAL fluid samples pre- and post-challenge were profiled using microarrays. Genes up-regulated by allergen challenge overlapped strongly with 11 genes up-regulated in DCs when stimulated by TSLP (TSLP-DC signature). The number of genes differentially expressed in response to challenge was reduced in aTSLPR-treated animals after 6 weeks relative to vehicle-treated animals. Expression of the TSLP-DC gene signature was also significantly reduced in aTSLPR-treated animals (p = 0.05). These results demonstrate promising efficacy for TSLPR blockade in an allergen challenge model where TSLP activation of DCs may play a key role.

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Cheng DT, Ma C, Niewoehner J, Dahl M, Tsai A, Zhang J, Gonsiorek W, Apparsundaram S, Pashine A, Ravindran P, Jung J, Hang J, Allard J, Bitter H, Tribouley C, Narula S, Wilson S, Fuentes ME