Efficacy and Safety of PL-5 Topical Spray for Burn Wound Infections: A Multicenter, Randomized, Double-Blind, Placebo-controlled, Phase IIIb Clinical Trial

Abstract Background Burn wound infections pose a significant global health burden. Antimicrobial peptides PL-5 spray is a novel topical antimicrobial agent for wound infections with superior clinical efficacy compared to positive drug in previous phase II and phase IIIa clinical studies. This phase IIIb clinical trial was conducted to further evaluate the efficacy and safety of PL-5 topical spray in treating burn wound infections. Methods A multicenter, randomized, double-blind, placebo-controlled trial was conducted across 23 centers in China. Eligible patients aged 18–65 with infected burn wounds were randomized in a 2:1 ratio to receive either PL-5 spray or placebo once daily for 14 days. The primary outcome was the complete healing rate on day 15 (D15). Secondary outcomes included clinical, microbiological, comprehensive efficacy evaluations and safety assessments. Results A total of 348 patients were randomized, with 232 receiving PL-5 and 116 receiving placebo. The complete wound healing rate on D15 was higher in the PL-5 group (64.3%) compared to the placebo group (43.1%) (P = 0.0002). The PL-5 group also showed superior microbiological efficacy on D15 (72.3% vs. 50.5%, P = 0.0001) and comprehensive efficacy (63.1% vs. 41.9%, P = 0.0003). No differences were observed in adverse events between groups, and no systemic absorption of PL-5 was detected. Conclusions PL-5 topical spray is effective in promoting wound healing and reducing bacterial load in burn wound infections, with a favourable safety profile. These findings support the potential of PL-5 as an effective alternative to traditional antibiotics in managing burn wound infections. Trial Registration ChiCTR2300071255.