Therapeutic Efficacy and Safety of Recombinant Botulinum Toxin Type A for Moderate to Severe Glabellar Lines: A Randomized, Controlled, Double-blind, Phase III Trial in Chinese Adults.

[BACKGROUND] Conventional botulinum toxin type A (BoNT/A) products include non-therapeutic accessory proteins vary in composition and manufacturing processes, which may contribute to differences in purity and biochemical characteristics. YY001（Retoxin） is a novel recombinant BoNT/A manufactured via E. coli expression to reduce impurities, improve purity, and minimize immunogenic risk.

[OBJECTIVES] To evaluate the efficacy, safety, and immunogenicity of YY001, a recombinant botulinum toxin type A (Chongqing Claruvis Pharmaceutical Co., Ltd., Chongqing, China), in the treatment of moderate to severe glabellar lines.

[METHODS] In this multicenter, randomized, double-blind, vehicle- and active-controlled Phase III trial, 529 adults aged 18-65 with moderate to severe glabellar lines were randomized 4:2:1 to receive a single 20 U injection of YY001, Botox®(Allergan Pharmaceuticals Ireland, Westport, Ireland), or vehicle. The primary endpoint was composite response rate (CRR) at Week 4, defined as a ≥2-grade improvement of glabellar line severity assessed by both investigator and participant. Secondary endpoints included onset time, duration, satisfaction, and safety.

[RESULTS] YY001 achieved a CRR of 86.7% at Week 4, significantly outperforming Botox® (66.7%, P < 0.0001) and vehicle (1.3%, P < 0.0001). It showed faster onset, longer median duration (97 days), and high participant satisfaction. Adverse events were mild and comparable across groups. Only one case of anti-drug antibody was observed; no neutralizing antibodies were detected. A 12-week follow-up and ethnically homogenous population may limit generalizability.

[CONCLUSIONS] YY001 demonstrated strong efficacy and a favorable safety profile than Botox®. Longer-term and multicenter studies are needed to assess durability, immunogenicity, and applicability across broader populations.