SIG1459: A novel phytyl-cysteine derived TLR2 modulator with in vitro and clinical anti-acne activity. Author José Fernández, Corey Webb, Karl Rouzard, Jason Healy, Masanori Tamura, Michael Voronkov, Kristen Huber, Jeffry Stock, Maxwell Stock, Joel Gordon, Edwardo Pérez Publication Year 2018 Type Journal Article Abstract Cutibacterium (formerly Propionibacterium acnes) is a major contributor to the pathogenesis of acne. C. acnes initiates an innate immune response in keratinocytes via recognition and activation of toll-like receptor-2 (TLR2), a key step in comedogenesis. Tetramethyl-hexadecenyl-cysteine-formylprolinate (SIG1459), a novel anti-acne isoprenylcysteine (IPC) small molecule, is shown in this study to have direct antibacterial activity and inhibit TLR2 inflammatory signalling. In vitro antibacterial activity of SIG1459 against C. acnes was established demonstrating minimal inhibitory concentration (MIC = 8.5 μmol\L), minimal bactericidal concentration (MBC = 16.1 μmol\L) and minimal biofilm eradication concentration (MBEC = 12.5 μmol\L). To assess SIG1459's anti-inflammatory activity, human keratinocytes were exposed to C. acnes and different TLR2 ligands (peptidoglycan, FSL-1, Pam3CSK4) that induce pro-inflammatory cytokine IL-8 and IL-1α production. Results demonstrate SIG1459 inhibits TLR2-induced IL-8 release from TLR2/TLR2 (IC = 0.086 μmol\L), TLR2/6 (IC = 0.209 μmol\L) and IL-1α from TLR2/TLR2 (IC = 0.050 μmol\L). To assess the safety and in vivo anti-acne activity of SIG1459, a vehicle controlled clinical study was conducted applying 1% SIG1459 topically (n = 35 subjects) in a head-to-head comparison against 3% BPO (n = 15 subjects). Utilizing the Investigator Global Assessment scale for acne as primary endpoint, results demonstrate 1% SIG1459 significantly outperformed 3% BPO over 8 weeks, resulting in 79% improvement as compared to 56% for BPO. Additionally, 1% SIG1459 was well tolerated. Thus, SIG1459 and phytyl IPC compounds represent a novel anti-acne technology that provides a safe dual modulating benefit by killing C. acnes and reducing the inflammation it triggers via TLR2 signalling. Keywords Humans, Signal Transduction, Oligopeptides, Female, Male, Cells, Cultured, Adult, Cysteine, Keratinocytes, Inflammation, Young Adult, Diglycerides, Peptidoglycan, Adolescent, Lipopeptides, Acne Vulgaris, Benzoyl Peroxide, Dermatologic Agents, Interleukin-1alpha, Interleukin-8, Proline, Propionibacterium acnes, Severity of Illness Index, Single-Blind Method, Toll-Like Receptor 2 Journal Exp Dermatol Volume 27 Issue 9 Pages 993-999 Date Published 2018 Sep ISSN Number 1600-0625 DOI 10.1111/exd.13692 Alternate Journal Exp Dermatol PMID 29797368 PubMedGoogle ScholarBibTeXEndNote X3 XML