Efficacy and Safety Evaluation of Pneumostem® Versus a Control Group for Treatment of BPD in Premature Infants

Inclusion Criteria: * Age: 5 - 14 days since birth * Fetal gestational age: ≥23 weeks and \<29 weeks * Birth weight: ≥500g and ≤1250g * Premature infant of equal to or less than 2 weeks of age who is receiving a ventilator therapy at a rate of \> 12 breath/min and \> 25% oxygen * Patient whose ventilator setting has not been changed and who has shown aggravation of the illness within the 24 hours prior to the study enrollment * Patient with a written consent form signed by a legal representative or a parent upon explanation of the clinical trial Exclusion Criteria: * Patient with concurrent cyanotic or acyanotic congenital heart diseases, except for patent ductus arteriosus * Patient with a concurrent severe lung malformation (i.e. Pulmonary hypoplasia, congenital diaphragmatic hernia, congenital cystic lung disease) * Patient with a concurrent severe lung malformation with chromosome anomalies (i.e. Edward syndrome, Patau syndrome, Down syndrome, etc) or severe congenital malformation (Hydrocephalus, Encephalocele, etc) * Patient with a concurrent severe congenital infection (i.e. Herpes, Toxoplasmosis, Rubella, Syphilis, AIDS, etc) * Patient withCRP \> 30 mg/dL; Severe sepsis or shock * Patient who is scheduled for or expected to undergo a surgical procedure 72 hours prior to/following the administration of the study drug * Patient who has been administered with a surfactant within the 24 hours prior to the administration of the study drug * Patient with severe intracranial hemorrhage ≥ grade 3 or 4 * Patient with active pulmonary hemorrhage or active air leak syndrome at the time of screening * Patient with a history of participating in other clinical studies * Patient who is allergic to Gentamicin * Patient who is considered inappropriate to participate in the study by the investigator