Pediatric patients with CD19+ acute lymphoblastic leukemia (ALL) undergoing chimeric antigen receptor T‐cell (CAR‐T) therapy frequently experience gastrointestinal (GI) complications. A retrospective study analyzed 13 patients (median age: 8 years) treated between January 2020 and January 2024. Seventy percent of patients experienced symptoms such as diarrhea (46%), abdominal pain (30%), and nausea/vomiting (38%). Despite adequate nutritional tolerance in 70% of cases, 31% required parenteral nutrition. Chronic malnutrition prevalence increased from 23% at baseline to 30% 6 months after therapy. These findings highlight the significant impact of CAR‐T therapy on GI health and nutritional status in pediatric patients. The high incidence of GI side effects and the associated nutritional challenges underline the importance of implementing multidisciplinary care and close monitoring to mitigate these complications. Optimizing nutritional management could improve patient outcomes and inform strategies for future treatments in this vulnerable population. Further research is needed to refine supportive care approaches.

Background/Objectives: Copper deficiency is described in adults on prolonged jejunal enteral nutrition, but paediatric evidence remains scarce. We compared the prevalence, timing and consequences of copper and other micronutrient deficiencies in children on prolonged jejunal versus gastric enteral nutrition. Methods: Ambispective observational cohort study at a tertiary paediatric centre. Children aged 0–18 years receiving at least 80% of their nutritional requirements through an enteral device for more than three months were studied; pre-existing malabsorption was an exclusion criterion. Groups were defined by feeding route (jejunal or gastric). Serum copper, zinc, iron and selenium were assessed longitudinally, with concurrent C-reactive protein < 2 mg/dL. Results: Forty-six patients were included (jejunal, 31; gastric, 15). Copper deficiency occurred in 9 of 31 jejunal patients (29.0%) and in no gastric patient (risk difference 29.0%, 95% CI 4.9–46.6%; p = 0.021). Iron deficiency was the commonest abnormality (71% versus 60%; p = 0.51). Six of the nine copper-deficient children developed anaemia or neutropenia; all normalised after oral copper sulfate given through the gastric route. Conclusions: In this single-centre cohort, prolonged jejunal feeding was associated with more frequent copper deficiency despite adequate intake; larger studies should confirm this. We suggest monitoring serum copper from three months after post-pyloric feeding starts.