KL4 Surfactant

KL4 Surfactant

Windtree’s KL4 surfactant technology produces a synthetic surfactant that is structurally similar to human pulmonary surfactant and contains a proprietary synthetic peptide KL4 (sinapultide), a 21-amino acid peptide that is designed to imitate the essential attributes of the human surfactant protein B (SP-B). SP-B is one of four known surfactant proteins and is the most important for proper functioning of the respiratory system. Windtree previously demonstrated in pre-clinical studies that KL4 surfactant may possess certain other beneficial properties, including modulation of the inflammatory process, antimicrobial properties and non-immunogenicity.1

KL4 surfactant can be produced in lyophilized (freeze-dried) form that is reconstituted to a liquid form prior to administration. In several experiments, Windtree believes that lyophilized KL4 surfactant may provide additional benefits over a liquid instillate in a clinical setting, potentially including:

  • improved ease of use for healthcare practitioners, including potential elimination of the drug warming process allowing for shortened preparation time; and potential reduction of continuous cold chain storage and refrigeration requirements;
  • potential for extended shelf life; and
  • relatively lower viscosity than that of a liquid instillate, which may aid and/or improve the distribution of KL4surfactant throughout the lung and potentially may reduce the frequency of transient peri-dosing events typically observed during administration of surfactants.

Windtree has also aerosolized its lyophilized KL4 surfactant and demonstrated that its aerosolized KL4 surfactant product candidate has the following important characteristics:

  • full retention of the surface-tension-lowering properties of a functioning surfactant necessary to restore lung function and maintain patency of the conducting airways;
  • full retention of the surfactant composition upon aerosolization; and
  • drug particle size believed to be suitable for deposition into the lung.

Windtree is initially developing aerosolized KL4 surfactant to treat RDS in premature infants, and thereafter, to potentially address a range of indications in neonatal, pediatric and adult critical care patient populations. We believe our KL4 surfactant in liquid, lyophilized and aerosolized forms may be developed to expand the therapeutic options available to treat previously unaddressed respiratory problems in patients of all ages.


1 Wolfson, M.R., Wu, J., Hubert, T.L., Gregory, T.J., Mazela, J., & Shaffer, T.H. (2012), “Lucinactant attenuates pulmonary inflammatory response, preserves lung structure, and improves physiologic outcomes in a preterm lamb model of RDS.” Pediatr Res, 72(4), 375-383; Black C, Leon C, Pluim J. Bactericidal properties of the novel, peptide-containing surfactant – Surfaxin®. Pediatric Academic Societies, Honolulu, HI, May, 2008. E?PAS2008:633756.11; and Clayton RG, Cochrane CG, Gregory TJ. Surfaxin® (lucinactant) does not induce an immune response in a standardized preclinical model. Pediatric Academic Societies, Honolulu, HI, May, 2008. E?PAS2008:633756.12.