Objective:

To evaluate blood eosinophil count trends and their predictive value for clinical response and endoscopic improvement in IBD patients receiving ustekinumab or adalimumab.

Key Findings:

• Ustekinumab responders for UC had significantly higher baseline eosinophil counts compared to non-responders (0.21 × 10^9/L vs 0.18 × 10^9/L, P = .042).
• By week 8, ustekinumab responders showed greater absolute (−0.07 × 10^9/L vs −0.01 × 10^9/L, P < .001) and percent declines (−33.33% vs −5.55%, P = .027) in eosinophil counts compared to non-responders.
• No significant differences in eosinophil counts were observed among CD patients treated with adalimumab or UC patients treated with vedolizumab.

Interpretation:

Eosinophil reduction may serve as an early marker for clinical response to ustekinumab in IBD, indicating its potential role in managing eosinophil-associated inflammation and guiding treatment decisions.

Limitations:

• The study's findings are based on data from clinical trials, which may not fully represent real-world patient populations, potentially limiting applicability.
• Eosinophil counts were not evaluated as a predictive marker for all treatment regimens, which may overlook other important factors.

Conclusion:

Targeting the IL-12/IL-23 pathway with ustekinumab may be more effective in managing eosinophil-associated inflammation in IBD compared to adalimumab.