Etrasimod Treatment Modulates Circulating and Lymph Node-Derived Lymphocytes in Crohn's Disease

Area of Science:

• Immunology
• Pharmacology
• Gastroenterology

Background:

• Etrasimod is an oral sphingosine-1 phosphate receptor modulator used for inflammatory bowel diseases.
• Its precise anti-inflammatory mechanism, particularly in lymph nodes, remains unclear.
• Previous studies noted peripheral blood lymphocyte reductions but lacked lymph node data.

Purpose of the Study:

• To investigate the effects of etrasimod on leukocyte subpopulations in peripheral lymph nodes and blood of Crohn's disease patients.
• To elucidate the pharmacodynamic mechanism of etrasimod in the context of T-cell mediated inflammation.

Main Methods:

• A randomized, double-blind, phase 2 CULTIVATE trial involving moderate-to-severe Crohn's disease patients.
• Collection of peripheral blood and inguinal lymph node biopsies at baseline and after 14 weeks of etrasimod treatment.
• Single-cell mass cytometry analysis of immune cell populations and T-cell subpopulations (CD4+, CD8+).

Main Results:

• Etrasimod treatment led to significant accumulation of naïve, central memory, and effector memory CD4+ T-cells, and naïve CD8+ T-cells in lymph nodes (p=0.03).
• Conversely, these T-cell subsets decreased significantly in peripheral blood (p=0.03).
• Naïve and memory B-cells decreased in circulation but remained unchanged in lymph nodes; innate immune cells were largely unaffected.

Conclusions:

• Etrasimod's pharmacodynamic effects are primarily associated with the attenuation of T-cell mediated inflammation.
• The drug causes a redistribution of T-cells from peripheral blood to lymph nodes.
• Further studies are needed to validate these findings in Crohn's disease treatment.