Recovery · FDA Approved
Sinapultide (KL4 Surfactant)
FDA-approved
01 · Overview
Sinapultide (KL4) is a synthetic 21-amino acid peptide that mimics surfactant protein B, a critical component of pulmonary surfactant. Combined with phospholipids it forms lucinactant (Surfaxin), a synthetic surfactant that lowers alveolar surface tension, and it was the first peptide-based replacement for surfactant protein B approved for clinical use (PMID 26970670).
It was developed primarily for preventing respiratory distress syndrome in premature infants (PMID 23473590), and has also been studied in acute lung injury.
02 · Research summary & key findings
In a randomized, masked trial of 1,294 very preterm infants, lucinactant reduced the rate of respiratory distress syndrome at 24 hours compared with the synthetic surfactant colfosceril palmitate (39.1 versus 47.2 percent) (PMID 15805380), and a meta-analysis found it as effective as animal-derived surfactants for prevention (PMID 23473590). The FDA approved lucinactant in 2012 for prevention of neonatal respiratory distress syndrome; the product is now listed as discontinued. In an open-label phase 1/2A trial in 19 adults with COVID-19 ARDS, intratracheal lucinactant did not significantly change oxygenation or lung compliance (PMID 42536986).
03 · Regulatory status
Sinapultide (KL4 Surfactant) has received FDA approval and is available for clinical use under appropriate medical supervision. Consult a qualified healthcare provider for prescribing information.
Sinapultide (KL4 Surfactant) is an FDA-approved medicine prescribed for the conditions on its label. It is not part of our intake, so we do not propose protocols for it. If you think it may be relevant to you, talk to your own doctor. How to ask your doctor.
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Sinapultide (KL4 Surfactant) is prescribed for the conditions on its label, and it is not part of our intake. If you are working on injury recovery and tissue repair, a licensed clinician can tell you at a free consultation whether an FDA-approved or lawfully compounded treatment fits you, or whether nothing does.
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04 · Administration routes
- Intratracheal instillation
References
- [1]A multicenter, randomized, masked, comparison trial of lucinactant, colfosceril palmitate, and beractant for the prevention of respiratory distress syndrome among very preterm infants Pediatrics, 2005. PMID 15805380
- [2]Lucinactant for the prevention of respiratory distress syndrome in premature infants Expert Rev Clin Pharmacol, 2013. PMID 23473590
- [3]Peptide-based synthetic pulmonary surfactant for the treatment of respiratory distress disorders Curr Opin Chem Biol, 2016. PMID 26970670
- [4]Lucinactant, a Synthetic Surfactant for the Treatment of Acute Respiratory Distress Syndrome Caused by COVID-19: Phase 1/2A Trial JMIR Form Res, 2026. PMID 42536986
Primary literature
- PubMed: "Sinapultide"
Peer-reviewed literature indexed by the National Library of Medicine.
- ClinicalTrials.gov: "Sinapultide"
Registered interventional and observational studies, including status and phase.
- PubChem: "Sinapultide"
Chemical structure, molecular properties, and bioactivity data.
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Disclaimer: This information is provided for educational and research purposes only. It is not intended as medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before starting any peptide therapy. The Peptide Association does not endorse or recommend any specific treatment protocol. See our editorial policy for how this content is produced and reviewed. Clinicians: join the network.