Calfactant (Infasurf®): A Comprehensive Monograph on its Pharmacology, Clinical Efficacy, and Safety in Neonatal Respiratory Distress Syndrome

Executive Summary

Calfactant, marketed under the brand name Infasurf®, is a sterile, non-pyrogenic, natural pulmonary surfactant of bovine origin. It is a cornerstone therapy in neonatal intensive care for the prevention and treatment of Neonatal Respiratory Distress Syndrome (RDS) in premature infants. Extracted from calf lungs using a distinct lung lavage method, Calfactant is a complex mixture of phospholipids, neutral lipids, and the critical hydrophobic surfactant-associated proteins B (SP-B) and C (SP-C). Its mechanism of action is to replace deficient or dysfunctional endogenous surfactant, rapidly adsorbing to the alveolar air-liquid interface to reduce surface tension. This biophysical action stabilizes the alveoli, prevents end-expiratory collapse (atelectasis), improves lung compliance, and facilitates effective gas exchange.

Clinical evidence has robustly demonstrated Calfactant's efficacy in decreasing the incidence of RDS, associated air leaks, and mortality due to RDS. Comparative trials have established its superiority over first-generation, protein-free synthetic surfactants and have shown it to be at least as effective as other natural surfactants, such as beractant, with potential advantages in duration of effect and speed of weaning from mechanical ventilation. Administration is exclusively intratracheal, requiring a highly controlled clinical setting and personnel experienced in the ventilatory management of premature neonates. The drug's potent and rapid pharmacodynamic effects necessitate immediate and frequent adjustments to ventilator support to prevent iatrogenic lung injury.