The US Food and Drug Administration has finally approved Discovery Lab's Surfaxin for the prevention of respiratory distress syndrome, a breathing disorder that affects premature infants.

The green light is based on a study which saw 1,294 premature infants receive either Surfaxin (lucinactant), the no-longer marketed Exosurf (colfosceril palmitate) or Abbott Laboratories' Survanta (beractant) within 30 minutes of birth. Surfaxin demonstrated significant improvement in both RDS at 24 hours after birth and RDS-related mortality through two weeks, when compared with Exosurf, which used to be sold by GlaxoSmithKline.

The FDA noted that the lungs of premature infants are not able to make enough surfactant, a liquid that coats the inside of the lungs and helps to keep them open. Without enough surfactant, the lungs collapse and the infant has difficulty breathing.

Surfaxin is the fifth drug approved in the USA to treat RDS in premature infants. Apart from Survanta and Exosurf, the others are Chiesi's Curosurf (poractant alpha) and Ony's Infasurf (calfactant).

The approval comes nearly two years after Discovery received a complete response letter from the FDA. In its letter, the agency's concerns focused primarily on "certain aspects of a Surfaxin biological activity test”, that had to be addressed before the application could be approved.

Discovery chief executive Thomas Amick said theapproval of Surfaxin is "an important medical advancement for theneonatology community and parents of preterm infants who will soon havean effective alternative to animal-derived surfactants to prevent thedevelopment of RDS". The treatment will be commercially available in the USA in late 2012.