In a double-blind, multicenter clinical study premature infants of birth weight between 500 and 1000 g, less than 30 weeks post-conceptional age, and with echocardiographic evidence of a PDA were randomized to placebo or Ibuprofen Lysine. These infants were asymptomatic from their PDA at the time of enrollment. The primary efficacy parameter was the need for rescue therapy (indomethacin, open-label ibuprofen, or surgery) to treat a hemodynamically significant PDA by study day 14. An infant was rescued if there was clinical evidence of a hemodynamically significant PDA that was echocardiographically confirmed. A hemodynamically significant PDA was defined by three of the following five criteria ― bounding pulse, hyperdynamic precordium, pulmonary edema, increased cardiac silhouette, or systolic murmur ― or hemodynamically significant ductus as determined by a neonatologist.
One hundred and thirty-six premature infants received either placebo or Ibuprofen Lysine (10 mg/kg on the first dose and 5 mg/kg at 24 and 48 hours). Mean birth age was 1.5 days (range: 4.6 – 73.0 hours), mean gestational age was 26 weeks (range: 23 – 30 weeks), and mean weight was 798 g (range: 530 – 1015 g). All infants had a documented PDA with evidence of ductal shunting. As shown in
Table 2, 25% of infants on Ibuprofen Lysine required rescue therapy versus 48% of infants on placebo (p=0.003 from logistic regression controlling for site).
Table 2. Summary of Efficacy Results, n (%) | Ibuprofen Lysine
N=68
| Placebo
N=68
|
|---|
| Required rescue through study day 14 | | |
| Total | 17 (25) | 33 (48) |
| By age at treatment | | |
| Birth to < 24 hours | 3/14 (21) | 8/16 (50) |
| 24-48 hours | 9/32 (28) | 16/37 (43) |
| > 48 hours | 5/22 (23) | 9/15 (60) |
| | |
| Echocardiographically proven PDA prior to rescue | 17 (100) | 32 (97) |
| Reasons for Rescue | | |
| Hemodynamically significant PDA per neonatologist | 14 (82) | 25 (76) |
| Bounding pulse | 6 (35) | 12 (36) |
| Systolic murmur | 6 (35) | 15 (45) |
| Pulmonary Edema | 3 (18) | 5 (15) |
| Hyperdynamic precordium | 2 (12) | 3 (9) |
| Increased cardiac silhouette | 1 (6) | 5 (15) |
Of the infants requiring rescue within the first 14 days after the first dose of study drug, no statistically significant difference was observed between the Ibuprofen Lysine and placebo groups for mean age at start of first rescue treatment (8.7 days, range 4-15 days, for the Ibuprofen Lysine group and 6.9 days, range 2-15 days, for the placebo group).
The groups were similar in the number of deaths by day 14, the number of patients on a ventilator or requiring oxygenation at day 1, 4 and 14, the number of patients requiring surgical ligation of their PDA (12%), the number of cases of Pulmonary Hemorrhage and Pulmonary Hypertension by day 14, and Bronchopulmonary Dysplasia at day 28. In addition, no significant differences were noted in the incidences of Stage 2 and 3 Necrotizing Enterocolitis, Grades 3 and 4 Intraventricular Hemorrhage, Periventricular Leukomalacia and Retinopathy of Prematurity between groups as determined at 36±1 weeks adjusted gestational age.
Two supportive studies also determined that ibuprofen, either prophylactically (n=433, weight range: 400 – 2165 g) or as treatment (n=210, weight range: 400 – 2370 g), was superior to placebo (or no treatment) in preventing the need for rescue therapy for a symptomatic PDA.