A Biomarker Signature to Predict Complete Response to Itacitinib and Corticosteroids in Acute Graft Versus Host Disease

BACKGROUND: Acute graft versus host disease (aGVHD) represents a serious and potentially life-threatening condition in patients receiving hematopoietic stem cell transplantation (HSCT). Development of aGVHD is characterized by increased levels of inflammatory mediators and activated T cells in circulation, leading to tissue and organ damage. Previously, we demonstrated that a panel measuring ST2, REG3A, and TNFR1 poorly predicted response to the combination of corticosteroids and itacitinib, a potent and highly selective JAK1 inhibitor, in a parallel-cohort phase 1 trial (NCT02614612). In this study, we utilized broad proteomic analysis to identify potentially predictive biomarkers of therapeutic response to the combination treatment. METHODS: Plasma samples were collected from 25 patients enrolled in the Phase 1 clinical trial prior to and at designated times following treatment. Broad proteomic analysis was conducted by OLINK Proteomics using a proximity extension assay. Selected biomarkers were quantitated by the same method based on standard curves generated using recombinant proteins. Statistical differences were identified using unpaired T tests and significance conferred when p