NEW YORK (September 25, 2026) – Researchers at the Icahn School of Medicine at Mount Sinai have identified biological mechanisms that may contribute to CAR-T cell-associated enterocolitis, a serious inflammatory condition of the intestine that can occur after a type of CAR-T cell therapy for multiple myeloma.
Published September 23 in Nature Medicine , the study found that CAR-T cells can persist in the intestinal tissue long after treatment and that patients who develop enterocolitis experience widespread changes in the immune system within the gut. The researchers also identified inflammatory pathways that may offer potential treatment targets.
CAR-T cell therapy uses a patient’s own immune cells, called T cells, that are genetically modified to recognize and attack cancer cells. A version of the therapy known as BCMA-directed CAR-T targets a protein called BCMA found on plasma cells, including the cancerous plasma cells involved in multiple myeloma. Some patients treated with these therapies develop persistent gastrointestinal symptoms, including diarrhea, abdominal pain, nausea, and weight loss.
“CAR-T therapy has transformed outcomes for many patients with blood cancers, but as these treatments become more widely used, we are also learning more about their long-term effects on the immune system,” said Saurabh Mehandru, MD, Professor of Medicine (Gastroenterology) at the Icahn School of Medicine at Mount Sinai and corresponding author of the study. “Our research provides the first detailed map of what happens in the intestine in patients who develop CAR-T-associated enterocolitis and identifies biological pathways that may be targeted therapeutically”
“CAR-T cell therapy has changed the treatment landscape for multiple myeloma, giving patients with difficult-to-treat disease new treatment options,” said Samir Parekh, MD, Professor of Medicine and Director of the Center of Excellence for Multiple Myeloma at the Icahn School of Medicine at Mount Sinai, and co-supervisor of the study. “As we use these therapies in more patients and earlier in the course of disease, it is increasingly important to understand and manage the complications that can occur. These findings provide important insight into why some patients develop severe intestinal inflammation and point to potential strategies for treating or preventing this complication.”
Key Findings
“This work provides a detailed view of the cellular changes associated with CAR-T-associated enterocolitis and shows that the condition involves multiple components of the intestinal immune environment,” said Nikhit Kethidi, MD, first authors of the study. “Understanding these changes may help identify new approaches to treating this complication and guide future studies of how to prevent or manage it.”
The findings also point to a potential approach to treatment. JAK inhibitors are medications that block proteins involved in inflammatory signaling. Two patients with CAR-T-associated enterocolitis who received upadacitinib, a medication that blocks JAK1, experienced improvements in symptoms, intestinal inflammation, and other measures of disease activity. In one patient, treatment was also associated with a substantial reduction in CAR-T cells in intestinal tissue.
The study was conducted by investigators from the Icahn School of Medicine at Mount Sinai in collaboration with researchers from Weill Cornell Medicine, Johns Hopkins University, Memorial Sloan Kettering Cancer Center, Stanford University School of Medicine, Harvard Medical School and Boston Children’s Hospital, Northwestern University Feinberg School of Medicine, Charité–Universitätsmedizin Berlin, Friedrich-Alexander-Universität Erlangen-Nürnberg, University Hospital Leipzig, and other national and international institutions.
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About the Mount Sinai Health System
Mount Sinai Health System is one of the nation’s leading integrated academic health systems and one of the largest in the New York metropolitan area. Its comprehensive system includes seven hospitals, more than 400 outpatient practices, over 600 research and clinical laboratories, the Icahn School of Medicine at Mount Sinai, the Graduate School of Biomedical Sciences, and the Mount Sinai Phillips School of Nursing. Together, the Health System comprises approximately 48,000 employees, more than 9,000 physicians, and 8,600 nurses.
As a leading learning health system, Mount Sinai combines clinical expertise with scientific discovery to improve patient care while training the next generation of health care and biomedical leaders. The Health System provides care across every stage of life, from prenatal care through geriatrics, while advancing personalized medicine through artificial intelligence, data science, and biomedical research.
Mount Sinai is consistently recognized among the nation’s leading academic health systems for patient care, research, and education. The Mount Sinai Hospital is ranked No. 1 in New York by Newsweek and No. 5 on the magazine’s World’s Best Hospitals list. The Icahn School of Medicine at Mount Sinai ranks No. 11 among U.S. medical schools and No. 1 among freestanding medical schools for National Institutes of Health funding, reflecting the strength of its scientific enterprise and leadership in biomedical research.
Nature Medicine
Persistence of mucosal CAR-T cells and inflammatory remodeling in enterocolitis associated with BCMA CAR-T cell therapy
23-Sep-2026