BACKGROUND: Hyaluronic acid (HA) is a widely used dermal filler for lip augmentation. IPN-20-SENSE LIDOCAINE (Laboratoires VIVACY) is a monophasic gel consisting of cross-linked HA and includes lidocaine hydrochloride for the reduction of injection-associated pain. AIMS: The SMILE study was designed to assess the non-inferiority of IPN-20-SENSE LIDOCAINE compared to HA-RK-Lido in improving aesthetic lip appearance. The secondary objectives were to evaluate the effectiveness and safety of IPN-20-SENSE LIDOCAINE against the chosen similar active control device. PATIENTS/METHODS: This was a prospective, multicenter, double-blinded, randomized active controlled parallel group study undertaken in two investigational sites between May 2021 and July 2022 (14 months). The primary endpoint of this study was the proportion of subjects reporting an improvement on the Global Aesthetic Improvement Scale (GAIS) 3 months after treatment initiation. RESULTS: Regarding the primary endpoint, the difference between the treatment arms in the proportion of improved subjects was +7.0 [-2.2
17.7]. The lower limit of this 90% CI, being above the non-inferiority margin of -15 and below zero, demonstrated the non-inferiority of IPN-20-SENSE LIDOCAINE vs. HA-RK-Lido. The secondary outcomes reported by subjects and the blinded live evaluators supported this result. All injection site reactions and device-related adverse events reported in this study were expected, already described and were mostly mild and transient. CONCLUSIONS: The study demonstrated the non-inferiority of IPN-20-SENSE LIDOCAINE to HA-RK-Lido in the aesthetic improvement of the lips. The effect of both treatments decreased over time. Nonetheless, aesthetic improvement was sustained longer in the IPN-20-SENSE LIDOCAINE arm. LEVEL OF EVIDENCE I: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .