Comparison 1. a1PI 60 mg/kg/dose for four doses versus placebo.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 CLD at 36 weeks amongst all randomised	2	151	Risk Ratio (M‐H, Fixed, 95% CI)	0.64 [0.35, 1.18]
2 CLD at 28 days amongst all randomised	2	151	Risk Ratio (M‐H, Fixed, 95% CI)	0.81 [0.64, 1.01]
3 Death by 36 weeks PMA amongst all randomised	2	151	Risk Ratio (M‐H, Fixed, 95% CI)	1.56 [0.58, 4.17]
4 Death by 28 days amongst all randomized	2	151	Risk Ratio (M‐H, Fixed, 95% CI)	1.71 [0.56, 5.24]
5 Death by 7 days amongst all randomised	1	106	Risk Ratio (M‐H, Fixed, 95% CI)	1.33 [0.31, 5.67]
6 Death or CLD by 36 weeks PMA amongst all randomised	2	151	Risk Ratio (M‐H, Fixed, 95% CI)	0.84 [0.53, 1.34]
7 Death or CLD by 28 days amongst all randomised	2	151	Risk Ratio (M‐H, Fixed, 95% CI)	0.87 [0.72, 1.05]
8 CLD by 36 weeks PMA amongst survivors	2	136	Risk Ratio (M‐H, Fixed, 95% CI)	0.67 [0.37, 1.24]
9 CLD by 28 days amongst survivors	2	140	Risk Ratio (M‐H, Fixed, 95% CI)	0.84 [0.68, 1.04]
10 Duration of requirement of supplemental oxygen amongst survivors (days)	1	97	Mean Difference (IV, Fixed, 95% CI)	‐11.20 [‐26.34, 3.94]
11 Duration of respiratory support amongst survivors (days)	2	138	Mean Difference (IV, Fixed, 95% CI)	‐5.61 [‐18.04, 6.82]
12 Requirement for systemic anti‐inflammatory therapy amongst survivors	1	97	Risk Ratio (M‐H, Fixed, 95% CI)	1.02 [0.76, 1.38]
13 Mortality prior to hospital discharge	1	106	Risk Ratio (M‐H, Fixed, 95% CI)	1.75 [0.54, 5.63]
14 Developmental delay amongst infants assessed	1	83	Risk Ratio (M‐H, Fixed, 95% CI)	1.29 [0.43, 3.90]