Failure of cromolyn sodium to reduce the incidence of bronchopulmonary dysplasia: a pilot study. The Neonatal Cromolyn Study Group. Cromolyn sodium prophylaxis inhibits pulmonary proinflammatory cytokines in infants at high risk for bronchopulmonary dysplasia.
This prospective, randomized, blinded clinical trial was conducted to test whether therapy with cromolyn sodium might decrease the incidence or severity of bronchopulmonary dysplasia when given to newborns with respiratory distress syndrome. Cromolyn (20 mg) or placebo was aerosolized to intubated newborns with respiratory distress syndrome every 6 hours, beginning on the first day of intubation. Patients were stratified by birth weight less than 1000 g and 1000 to 2000 g; primary outcome success was defined as survival to 30 days without oxygen dependence. Of 10 patients enrolled who were less than 1000 g birth weight, there were no treatment successes, preventing outcome analysis. The study was discontinued after 28 patients of 1000 to 2000 g birth weight had been studied, at which time it had been found with 95% confidence, with a power of .80, that cromolyn sodium did not decrease by 50% the incidence of bronchopulmonary dysplasia. Severity of bronchopulmonary dysplasia was also similar, with 4 patients in the treatment group and 3 in the placebo group receiving mechanical ventilation at 30 days. Possible reasons for this study outcome include (1) a delivered dose too small to produce a clinical effect; (2) the start of therapy too late to prevent the onset of inflammation; (3) inadequate effect of cromolyn on polymorphonuclear cells in vivo; or (4) development of bronchopulmonary dysplasia through factors unaffected by the actions of cromolyn. An imbalance of proinflammatory cytokines such as TNF-alpha, IL-1 beta, and the neutrophil chemotactic factor IL-8 and inhibitors (e.g., soluble TNF receptors and IL-1ra) in the lung during the first week of life may contribute to prolonged pulmonary inflammation and fibrosis in bronchopulmonary dysplasia (BPD). Disodium cromoglycate (DSCG) has anti-inflammatory effects in asthma, a disease with many similarities with BPD. In a prospective, randomized, blinded study, we examined whether early DSCG therapy inhibits proinflammatory cytokines in infants at risk for BPD. Twenty-six infants who were identified as high risk (> or = 75% probability) for oxygen-dependency at 28 d by a 12-h predictive score and survived 48 h were randomized to nebulized DSCG 20 mg (n = 13) or 2 cc NS (control, n = 13) every 6 h from Day 3 to Day 28. Lung lavage was collected on Day 3 (pre-study) and Day 7 and analyzed for cell count and differential and TNF-alpha, sTNFR1, sTNFR2, IL-1 beta, IL-1ra, and IL-8 concentrations. The groups' pre-study lavage cytokine concentrations were similar, but TNF-alpha and IL-8 concentrations were 3.6- and 4.9-fold lower in the DSCG group on Day 7 compared with levels in the control group. Soluble TNF receptors were unaffected by DSCG. There was a trend towards lower IL-1 beta levels in DSCG-treated infants on Day 7, but IL-1ra levels were unaffected by DSCG therapy. Three control subjects, but no DSCG-treated infants, died during the study period (p = 0.07). There were no significant differences between survivors of the two groups for oxygen-dependency at 28 d (100% control subjects; 85% DSCG). These results suggest that nebulized DSCG may exert an anti-inflammatory effect in the lungs of infants < or = 1,000 g at risk for BPD.
There is currently no evidence from randomised trials that cromolyn sodium has a role in the prevention of CLD. Cromolyn sodium cannot be recommended for the prevention of CLD in preterm infants.