MATERIALS AND METHODS
This was a prospective, randomized, double-blind, doseranging, phase 2 clinical study conducted across 4 sites in Germany and 5 in the USA (ClinicalTrials.gov identification number: NCT03806933; EudraCT identification number 2018- 002743-28). The study was conducted in compliance with the Declaration of Helsinki and Good Clinical Practice principles. All subjects provided written informed consent prior to beginning any study-related procedures.
The subjects were followed from treatment until return to baseline GFL wrinkle severity as determined by a blinded investigator assessment at maximum frown on the Facial Wrinkle Scale (FWS), a widely-used, 4-point, standardized, assessment scale for glabellar line severity (0=no muscle action at all, 1=some even slight muscle action possible, 2=moderately strong muscle action possible, 3=strong muscle action possible that may cause local pallor). Subjects were required to remain in the study for at least 180 days and no longer than 360 days, depending on return to baseline wrinkle severity. This was defined as the main period of the study.
Subjects
Male and female subjects (≥18 years of age) with moderate to severe GFL (FWS score of 2–3) according to both subject and investigator assessment at maximum frown were eligible for this study. Key exclusion criteria included: treatment with BoNT (any serotype) in the facial area, any facial cosmetic procedure in the glabella area, or any biodegradable filler in the glabella within past 12 months; any previous insertion of permanent material in the glabella area; and planned cosmetic treatment of the face during the study period.
Treatment
The treatment procedures, which were identical in stage 1 and stage 2, were previously described.16 Briefly, subjects received a single GFL treatment on day 1, with an optional follow-up treatment (20U INCO) for subjects who had completed the main period of the study. In stage 1, subjects were randomized 1:2:2 to receive 20, 50, or 75U INCO. In stage 2, subjects were randomized 1:2 to receive 20 or 100U INCO. Subjects did not cross over from stage 1 to stage 2. Before injection, INCO was reconstituted with unpreserved, sterile 0.9% saline solution. To maintain blinded status, the injection volume was constant across all dose groups. A total injection volume of 0.25 ml was used in blinded syringes. Investigators administered the injections with a 30 G or 32 G needle in equal aliquots of 0.05 mL into each of 5 injection sites of the procerus and corrugator muscles.
Primary Efficacy Endpoint
The primary efficacy endpoint was duration of ≥1-point improvement from baseline on FWS as assessed by investigator at maximum frown.
Secondary Efficacy Endpoints
Secondary efficacy endpoints included:
• The duration of effect of a FWS score as rated by investigator of none (0) or mild (1) at maximum frown from treatment until return to a score of moderate (2) or severe (3).
• The duration of effect of a ≥2-point improvement as rated by investigator from baseline at maximum frown on the FWS.
• The percentage of subjects rated by investigator and the percentage of subjects rated by themselves as none (0) or mild (1) at maximum frown on FWS at day 180.
• The percentage of subjects rated by investigator and the percentage of subjects rated by themselves as at least 1-point improvement from baseline at maximum frown on FWS at day 180.
In addition, the percentage of subjects fulfilling the above effect definitions at day 30, 60, 90, 120, and 150 were analyzed as other efficacy variables, as well as the percentage of subjects rated by themselves as improved or better on the Global Aesthetic Improvement Scale (GAIS) from day 30 to 180.
Primary Safety Endpoints
Primary safety endpoints included the occurrence of treatmentemergent AEs (TEAEs), treatment-emergent serious AEs (TESAEs), treatment-emergent AEs of special interest (TEAESI), related TEAEs, and related TESAEs by dose group. TEAE was defined as an AE that began or worsened on or after the date of the first administration of treatment.
Statistical Analysis
Efficacy analyses were conducted on the full analysis set (FAS, all randomized subjects) and safety analyses on the safety evaluation set (SES, all treated subjects) using SAS® version 9.4 (Cary, NC, USA).
Primary and secondary duration of effect variables were analyzed by Kaplan-Meier curves per dose group and the respective medians of times with 2-sided 95% confidence intervals (CIs). Cox proportional hazard regression models with factors dose group, study site, and baseline investigator-assessed FWS score at maximum frown were performed for exploratory purposes. For binary efficacy variables and safety endpoints, descriptive analyses were conducted.
Determination of Sample Size
To detect AEs with an incidence rate of 3% at least once per dose group with a probability of approximately 80%, a sample size of 53 subjects per group was necessary. Assuming an exponential distribution, a median duration of effect of 3 months and a censoring rate of 5%, a minimum of 55 subjects per group were needed to obtain a precision of 1.1 months with 80% probability and a precision of 1.5 months with 90% probability when estimating median duration of effect. In total, 60 subjects per dose group were deemed necessary.
The subjects were followed from treatment until return to baseline GFL wrinkle severity as determined by a blinded investigator assessment at maximum frown on the Facial Wrinkle Scale (FWS), a widely-used, 4-point, standardized, assessment scale for glabellar line severity (0=no muscle action at all, 1=some even slight muscle action possible, 2=moderately strong muscle action possible, 3=strong muscle action possible that may cause local pallor). Subjects were required to remain in the study for at least 180 days and no longer than 360 days, depending on return to baseline wrinkle severity. This was defined as the main period of the study.
Subjects
Male and female subjects (≥18 years of age) with moderate to severe GFL (FWS score of 2–3) according to both subject and investigator assessment at maximum frown were eligible for this study. Key exclusion criteria included: treatment with BoNT (any serotype) in the facial area, any facial cosmetic procedure in the glabella area, or any biodegradable filler in the glabella within past 12 months; any previous insertion of permanent material in the glabella area; and planned cosmetic treatment of the face during the study period.
Treatment
The treatment procedures, which were identical in stage 1 and stage 2, were previously described.16 Briefly, subjects received a single GFL treatment on day 1, with an optional follow-up treatment (20U INCO) for subjects who had completed the main period of the study. In stage 1, subjects were randomized 1:2:2 to receive 20, 50, or 75U INCO. In stage 2, subjects were randomized 1:2 to receive 20 or 100U INCO. Subjects did not cross over from stage 1 to stage 2. Before injection, INCO was reconstituted with unpreserved, sterile 0.9% saline solution. To maintain blinded status, the injection volume was constant across all dose groups. A total injection volume of 0.25 ml was used in blinded syringes. Investigators administered the injections with a 30 G or 32 G needle in equal aliquots of 0.05 mL into each of 5 injection sites of the procerus and corrugator muscles.
Primary Efficacy Endpoint
The primary efficacy endpoint was duration of ≥1-point improvement from baseline on FWS as assessed by investigator at maximum frown.
Secondary Efficacy Endpoints
Secondary efficacy endpoints included:
• The duration of effect of a FWS score as rated by investigator of none (0) or mild (1) at maximum frown from treatment until return to a score of moderate (2) or severe (3).
• The duration of effect of a ≥2-point improvement as rated by investigator from baseline at maximum frown on the FWS.
• The percentage of subjects rated by investigator and the percentage of subjects rated by themselves as none (0) or mild (1) at maximum frown on FWS at day 180.
• The percentage of subjects rated by investigator and the percentage of subjects rated by themselves as at least 1-point improvement from baseline at maximum frown on FWS at day 180.
In addition, the percentage of subjects fulfilling the above effect definitions at day 30, 60, 90, 120, and 150 were analyzed as other efficacy variables, as well as the percentage of subjects rated by themselves as improved or better on the Global Aesthetic Improvement Scale (GAIS) from day 30 to 180.
Primary Safety Endpoints
Primary safety endpoints included the occurrence of treatmentemergent AEs (TEAEs), treatment-emergent serious AEs (TESAEs), treatment-emergent AEs of special interest (TEAESI), related TEAEs, and related TESAEs by dose group. TEAE was defined as an AE that began or worsened on or after the date of the first administration of treatment.
Statistical Analysis
Efficacy analyses were conducted on the full analysis set (FAS, all randomized subjects) and safety analyses on the safety evaluation set (SES, all treated subjects) using SAS® version 9.4 (Cary, NC, USA).
Primary and secondary duration of effect variables were analyzed by Kaplan-Meier curves per dose group and the respective medians of times with 2-sided 95% confidence intervals (CIs). Cox proportional hazard regression models with factors dose group, study site, and baseline investigator-assessed FWS score at maximum frown were performed for exploratory purposes. For binary efficacy variables and safety endpoints, descriptive analyses were conducted.
Determination of Sample Size
To detect AEs with an incidence rate of 3% at least once per dose group with a probability of approximately 80%, a sample size of 53 subjects per group was necessary. Assuming an exponential distribution, a median duration of effect of 3 months and a censoring rate of 5%, a minimum of 55 subjects per group were needed to obtain a precision of 1.1 months with 80% probability and a precision of 1.5 months with 90% probability when estimating median duration of effect. In total, 60 subjects per dose group were deemed necessary.
