First In Human Study on Synthetic Surfactant CHF 5633 in Respiratory Distress Syndrome

Inclusion Criteria: * Written informed consent obtained by parents/legal representative (according to local regulation) prior to any study-related procedures * Inborn and outborn, preterm neonates of either sex with a gestational age of 27 weeks up to 33 weeks+6 * Clinical and radiological findings typical of RDS * Age on admission to the study \< 24 hours from birth * Requirement of endotracheal intubation for surfactant administration * Fraction of inspired oxygen (FiO2) \> 0.35 to maintain SpO2 between 90-95 % * Documentation of normal cranial ultrasound scan Exclusion Criteria: * Use of surfactant prior to study entry and need for intratracheal administration of any other treatment (e.g. nitric oxide) * Known genetic or chromosomal disorders, major congenital anomalies (cardiac malformations, myelomeningocele etc) * Maternal drug abuse (heroin, methadone, methamphetamine, or cocaine) or significant alcohol consumption during pregnancy * Clinical chorioamnionitis (Appendix III) * Strong suspicion of congenital pneumonia/infection, sepsis * Evidence of severe birth asphyxia or a 5 minutes Apgar score less / equal 3 * Presence of air leaks prior to study entry * Neonatal seizures prior to study entry * Mothers with prolonged rupture of the membranes (\> 3 weeks duration) * Any condition that, in the opinion of the Investigator, would place the neonate at undue risk * Participation in another clinical trial of any placebo, drug or biological substance conducted under the provisions of a protocol