Bispecific Antibody Targeting Both IL33 and TSLP for Asthma and COPD

Abstract RATIONALE: Asthma and chronic obstructive pulmonary disease (COPD) are persistent inflammatory airway disorders characterized by obstructive airflow limitation, imposing a substantial burden on both patients and healthcare systems. Alarmins IL33 and TSLP have been established as validated therapeutic targets for the treatment of asthma and COPD. Notably, IL33 and TSLP are the only targets that have demonstrated clinical efficacy in non-Th2 asthma settings. Here we engineered and produced HXN-1013, a bispecific antibody (bsAb) simultaneously targeting both TSLP and IL33, with the aim to further enhance clinical efficacy for the treatment of asthma and COPD patients. METHODS: anti-TSLP antibodies were generated, characterized and selected through various in vitro assays, including TSLPR-STAT5-Luc reporter assays, TSLP-induced Baf3 proliferation, and CCL17 release from PBMCs. IL33 antibodies were generated and assessed using IL33 reporter assay, and L33 induced PBMC activation assay. The synergistic effect of dual targeting was measured by IL5 and IL13 release in human PBMCs co-stimulated with TSLP and IL33. RESULTS: Multiple anti-TSLP antibodies were generated with high potency and different binding epitopes, including antibodies targeting TSLP Site I (TSLPR binding site), Site II (IL7Rα binding site), and biparatopic antibodies that simultaneously targeting both site I and II. In TSLPR/STAT5 reporter assays and BaF3 proliferation assays, these antibodies demonstrated a significant activity advantage compared to Tezepelumab. We produced a number of anti-IL33 antibodies with superior potency compared to Itepekimab based on IL33 reporter assays and PBMC activation assays. Based on these building blocks, we engineered a bispecific antibody, HXN-1013, that is capable of simultaneously binding to both TSLP and IL33 and blocking the cytokines from interacting with it respective receptor. Each arm of the bsAb demonstrated a biological activity comparable to the parental antibodies. In the PBMC activation assay induced by both TSLP and IL33, the bsAb showed superior activity than each of the individual parent antibodies. CONCLUSIONS: HXN-1013 simultaneously blocks TSLP and IL33, with each arm exhibiting activity comparable to the parent antibodies. HXN-1013 has great potential to enhance clinical efficacy for the treatment of asthma and COPD.