P0164Zasocitinib (TAK-279), an investigational oral, allosteric, highly selective and potent TYK2 inhibitor preserves anti-inflammatory IL-10 signalling in vitro

Background Zasocitinib (TAK-279) is an investigational, oral, allosteric, highly selective and potent tyrosine kinase 2 (TYK2) inhibitor in clinical development for immune-mediated inflammatory diseases (IMIDs), including Inflammatory Bowel Disease (IBD). TYK2 mediates signalling downstream of IL-12, IL-23 and type I IFN, which drive immune responses that perpetuate intestinal inflammation. IL-10 is a key anti-inflammatory cytokine that signals via the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway to limit pro-inflammatory cytokine production and maintain mucosal immune tolerance. Loss of IL-10 or IL-10 receptor signalling leads to very early-onset IBD, highlighting its essential role in preserving gut homeostasis and supporting regulatory T cell activity. This study assessed the effect of zasocitinib, deucravacitinib (TYK2 inhibitor) and upadacitinib (JAK1 inhibitor) treatment on IL-10 signalling. Methods Human whole blood from healthy volunteers (n = 12) was incubated with increasing concentrations (0.51 nM–10 μM) of zasocitinib, deucravacitinib or upadacitinib, and stimulated with IL-10 (10 ng/mL). IL-10 signalling was assessed by phosphorylated STAT3 (pSTAT3) relative to non-cytokine treated pSTAT3 signal via flow cytometry, and half maximal inhibitory concentrations (IC50) were calculated. IL-10-dependent (10 ng/mL) suppression of lipopolysaccharide (10 μg/mL)-induced IL-1β, IL-6 and TNFα was measured in human whole blood following treatment with 10 μM of zasocitinib (n = 11), deucravacitinib (n = 11) or upadacitinib (n = 7). RNA sequencing evaluated IL-10-responsive gene expression in whole blood from healthy volunteers (n = 4) treated with up to 10 μM of zasocitinib, deucravacitinib or upadacitinib. Results In the IL-10-pSTAT3 assay, an IC50 value could not be determined for zasocitinib, suggesting preservation of IL-10 signalling. IC50 values for deucravacitinib and upadacitinib were 331 (95% CI 301–365) nM and 307 (263–362) nM, respectively. IL-10-mediated suppression of IL-1β, IL-6 and TNFα was preserved with zasocitinib; deucravacitinib and upadacitinib significantly attenuated IL-10-mediated cytokine suppression (Figure 1). Following IL-10 stimulation, 28 out of the top 30 upregulated genes continued to be expressed after treatment with zasocitinib versus 6/30 and 12/30 with deucravacitinib and upadacitinib, respectively. Conclusion Zasocitinib preserved IL-10 signalling and suppression of pro-inflammatory cytokines. Given the immunosuppressive role of IL-10 in IBD, these observations support the ongoing investigation of zasocitinib as a potential therapeutic for patients. Ongoing clinical trials will further evaluate efficacy and safety of zasocitinib in patients with IMIDs, including IBD. Conflict of interest: Dr. Orlandi, Chiara: Employee of Takeda Development Center Americas, Inc. Lin, Kuan-Yin: Employee of Takeda Development Center Americas, Inc Kumar, Sachin: Employee of Takeda Development Center Americas, Inc Sherlock, Jonathan: Employee of Takeda Development Center Americas, Inc Wilson, Elizabeth: Employee of Takeda Development Center Americas, Inc Petrakis, Ioannis: Employee of Takeda Development Center Americas, Inc Salas, Azucena: Received research grants from AbbVie, Pfizer and Takeda.