The purpose of this study is to identify the safest dose of recombinant surfactant protein D (drug name: rfhSP-D) that can be administered to preterm infants born at less than 30 weeks gestation, and to help identify whether this can prevent the development of neonatal chronic lung disease.

This is a Phase I, dose escalation safety study that aims to identify the recommended phase 2 dose of recombinant fragment of human surfactant protein D (rfhSP-D) (drug name: rfhSP-D) for infants at risk of neonatal chronic lung disease. This study will aim to establish if the administration of rfhSP-D to the lungs of preterm babies, via an endotracheal tube, is safe at the proposed dosage range (1mg/kg - 4mg/kg) and whether this dose results in detectable concentrations in lung secretions or serum.

Surfactant protein D (SP-D) is a naturally occurring component of the surfactant system with anti-inflammatory properties. Current surfactant replacement therapy contains phospholipids and surfactant proteins B and C (SP-B and SP-C) but no surfactant protein A (SP-A) or surfactant protein D (SP-D).

Proof of concept regarding the anti-infective and anti-inflammatory activity of SP-D has been achieved in mouse and a preterm lamb models of lung disease and supports increasing evidence of the role played by deficiency of SP-D in human respiratory diseases.

Subjects will be enrolled in cohorts with increasing dose. Whether or not the dose is escalated will depend on the occurrence of dose limiting events (DLE) in all current patients and the doses that they have received. A model will be used to estimate the risk of DLE per dose level. Initial estimates of these risks will be updated using data collected throughout the trial.

Up to 24 infants of less than 30 weeks gestation will be recruited in the study and receive intra-tracheal administration of SP-D59, in the dose range 1mg/kg, 2mg/kg or 4mg/kg per dose for up to 3 doses. The first dose of SP-D59 will be given as soon as possible after the first dose of standard surfactant therapy (e.g., Curosurf). Subsequent doses of the IMP will be given at 12 hours and 24 hours after the first dose was administered.

Participant Inclusion Criteria:

1. Inborn infants born at between 23 weeks and 0 days and 29 weeks and 6 days gestation.
2. Infant must be intubated or planned to be intubated for respiratory distress at time of eligibility check, and this should be done within 12 hours from time of birth.
3. Receiving standard surfactant therapy
4. Clinically stable on mechanical ventilation. Stability is defined at the time of IMP instillation and is defined below.
5. Written informed consent from parents/guardians/person with legal responsibility

Definition of stability:

1. Blood gases within the normal range for preterm infants (pH>7.20; paCO2 <60mmHg)
2. Mean blood pressure with or without inotropic support at at least gestational age or above (mmHg)
3. No evidence of a pneumothorax
4. Clinical observations within acceptable range for an infant of that gestational age
5. No stability concerns from the attending neonatologist

Participant Exclusion Criteria:

1. Congenital anomalies i.e any major antenatal diagnosed congenital abnormalities such as congenital heart disease, suspected or known chromosomal abnormalities
2. Parents/legal guardians unable to give consent due to learning or other difficulties
3. Infants requiring only CPAP support without the need for surfactant replacement therapy, i.e. without endotracheal intubation
4. Infants born in very poor condition and judged too sick or unstable to be included (high risk of mortality) in an experimental first in human study, for example infants that are requiring maximal intensive care therapy and have findings such as a grade IV intraventricular haemorrhage that is likely to be life limiting.
5. Infants that are born out of the participating site.
6. Participation in any other interventional study (participation in an observational study is permissible).

There is currently no plan to make individual participant data available to other researchers. Written requests will be considered by the RESPONSE Trial Management Group.