Two-Year Follow-Up Outcomes of Premature Infants Enrolled in the Phase I Trial of Mesenchymal Stem Cells Transplantation for Bronchopulmonary Dysplasia

Objective To determine the long-term safety and outcomes of mesenchymal stem cells (MSCs) for bronchopulmonary dysplasia in premature infants enrolled in a previous phase I clinical trial up to 2 years of corrected age (CA). Study design We assessed serious adverse events, somatic growth, and respiratory and neurodevelopmental outcomes at visit 1 (4-6 months of CA), visit 2 (8-12 months of CA), and visit 3 (18-24 months of CA) in a prospective longitudinal follow-up study up to 2 years' CA of infants who received MSCs (MSC group). We compared these data with those from a historical case-matched comparison group. Results One of 9 infants in the MSC group died of Enterobacter cloacae sepsis at 6 months of CA, the remaining 8 infants survived without any transplantation-related adverse outcomes, including tumorigenicity. No infant in the MSC group was discharged with home supplemental oxygen compared with 22% in the comparison group. The average rehospitalization rate in the MSC group was 1.4/patient because of respiratory infections during 2 years of follow-up. The mean body weight of the MSC group at visit 3 was significantly higher compared with that of the comparison group. No infant in the MSC group was diagnosed with cerebral palsy, blindness, or developmental delay; in the comparison group, 1 infant was diagnosed with cerebral palsy and 1 with developmental delay. Conclusions Intratracheal transplantation of MSCs in preterm infants appears to be safe, with no adverse respiratory, growth, and neurodevelopmental effects at 2 years' CA.