A groundbreaking case report published in The New England Journal of Medicine describes the first successful use of CD19 CAR T-cell therapy in treating severe, multidrug-resistant ulcerative colitis, achieving complete remission in a 21-year-old patient who had exhausted all conventional treatment options.
The patient, who had declined colectomy, experienced treatment failure with an extensive list of therapies including prednisolone, mesalamine, infliximab, ustekinumab, ozanimod, filgotinib, vedolizumab, upadacitinib, and cyclosporine combined with mirikizumab-mrkz. Even blinatumomab, a CD19-directed T-cell engager, produced only transient improvement without sustained B-cell depletion.
Novel Therapeutic Approach
The research team, led by Markus F. Neurath of Friedrich-Alexander-University Erlangen–Nuremberg, opted for CD19 CAR T-cell therapy based on evidence of dysregulated mucosal B-cell responses in ulcerative colitis. This decision challenged conventional understanding, as ulcerative colitis was previously considered largely B-cell independent, particularly given that rituximab treatment showed no efficacy in this condition.
Following standard lymphodepleting chemotherapy, the patient received autologous CD19 CAR T-cell infusion at 1 × 10⁶ cells/kg. The CAR T cells rapidly expanded, resulting in both peripheral and mucosal B-cell depletion.
Remarkable Clinical Outcomes
The treatment achieved unprecedented results within 14 weeks of follow-up. The patient experienced complete clinical, biochemical, and mucosal remission without requiring any concomitant therapy. Endoscopic, histologic, and ultrasonographic evaluations demonstrated clear evidence of mucosal healing over time.
Beyond the clinical markers, the patient gained 9 kg (20 pounds) in body weight and was able to resume her professional activities, representing a dramatic improvement in quality of life. The therapeutic response was associated with reduced levels of secretory IgA in the stool and loss of serum anti–integrin αvβ6 antibodies.
Safety Profile
The treatment demonstrated a favorable safety profile. The patient experienced only a spontaneously resolving grade 1 cytokine-release syndrome event on day 3 post-infusion. Additional documented findings included asymptomatic hypogammaglobulinemia and an isolated event of neutropenia, which was managed with a single dose of granulocyte colony-stimulating factor.
Clinical Implications
This case represents a paradigm shift in understanding ulcerative colitis pathophysiology and treatment approaches. According to the investigators, mucosal inflammation in ulcerative colitis involves infiltration of both adaptive immune cells (T cells, B cells, plasmablasts) and innate immune cells (neutrophils, macrophages). While current therapies target T-cell trafficking and cytokine production, they do not address the activated B-cell compartment.
The success of CD19 CAR T-cell therapy suggests that B-cell depletion may be a viable therapeutic strategy for patients with refractory ulcerative colitis. This finding is particularly significant given that many patients do not respond to current targeted treatments and continue to experience abdominal pain, bloody diarrhea, poor quality of life, and disease-associated complications including colorectal cancer risk.
Future Research Directions
The investigators emphasized the preliminary nature of these findings, noting that "because these findings are based on a single case, more patients with ulcerative colitis will need to be treated with CD19 CAR T cells to interpret the safety and efficacy of this treatment and to evaluate whether certain subgroups of patients are particularly prone to treatment response."
The case builds on previous evidence from a case series indicating that CD19 CAR T-cell therapy might induce deep tissue depletion of B cells and plasmablasts in B-cell–mediated autoimmune diseases. If these results can be replicated in larger studies, CAR T-cell therapy may expand its therapeutic reach far beyond current autoimmune indications, potentially reshaping treatment approaches for severe inflammatory bowel disease.
