Comparative trial of a novel botulinum neurotoxin type A versus onabotulinumtoxinA in the treatment of glabellar lines: a multicenter, randomized, double-blind, active-controlled study

A multicenter, double-blind, randomized, parallel-group, active-controlled, phase 3 clinical trial to compare the effectiveness and safety of two botulinum toxin type A formulations for improving moderate to severe glabellar wrinkles in Asians

Botulinum toxin type A (BoNT-A) was first isolated in 1946, and since then, several formulations have been developed and widely used to treat wrinkles by inducing muscle paralysis. This multicenter, double-blind, randomized, parallel-group, active-controlled phase 3 clinical trial was designed to evaluate the efficacy and safety of a newly developed BoNT-A formulation, BMI2006, in improving moderate to severe glabellar wrinkles and to compare with existing onabotulinumtoxin A (OBoNT) injections. A total of 276 subjects were enrolled and received 20 units of the randomized material, which was intramuscularly injected into five different locations on the forehead. The primary endpoint, assessed at 4 weeks, showed no statistically significant difference in the improvement rate of glabellar wrinkles between the two groups, with BMI2006 demonstrating non-inferiority to comparator BoNT-A. Secondary endpoints, evaluated by both treating investigators and independent investigators, also exhibited similar improvement rates throughout the study period. Both groups reported high levels of satisfaction with no statistical difference between the two groups. Safety evaluations indicated mild and transient adverse events, with no serious reactions observed. In conclusion, BMI2006 is an effective and safe BoNT-A for treating glabellar wrinkles with an expected duration of action between 8 and 12 weeks.

Efficacy and Safety of Botulinum Toxin Type A for Treatment of Glabellar Lines: A Network Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Botulinum toxin type A (BoNT/A) has been used in aesthetic applications worldwide, including glabellar lines. Currently, four BoNT/A preparations were approved for the improvement of moderate-to-severe glabellar lines: onabotulinumtoxinA, abobotulinumtoxinA, incobotulinumtoxinA, and prabotulinumtoxinA. DaxibotulinumtoxinA is a new form of BoNT/A drug that is developed in clinical application. We performed this network meta-analysis (NMA) to assess the efficacy and safety of all these different BoNT/A formulations for treating glabellar lines.

METHODS

The investigators searched randomized controlled trials (RCTs) using the Medical Subject Headings (MeSH) terms "botulinum toxin" and "glabellar lines." We searched the relevant studies in electronic databases as following: PubMed, Elsevier, EMBASE and the Cochrane Library. The end points included the percentage of subjects with a glabellar line severity (GLS) score of none (0) or mild (1), and the percentage of subjects achieving ≥ 1-point and 2-point improvement in glabellar line severity at maximum frown at approximately month 1 by the investigators' assessment.

RESULTS

All formulations of BoNT/A were far superior to placebo in efficacy. DaxibotulinumtoxinA was the only treatment that significantly increased the proportion of subjects achieving ≥ 1 point improvement in GLS score compared with other BoNT/A formulations. Moreover, daxibotulinumtoxinA was ranked the highest for the proportion of subjects achieving ≥ 2-point improvement in GLS score. No significant differences were revealed for the incidence of any adverse events (AEs) that related to treatment or drug among all BoNT/A preparations.

CONCLUSION

The overall results of this NMA suggested that daxibotulinumtoxinA is a new BoNT/A preparation that may be not only more effective but also well-tolerated for the treatment of glabellar lines.

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 .

PrabotulinumtoxinA vs OnabotulinumtoxinA for the Treatment of Adult Males With Moderate to Severe Glabellar Lines: Post-hoc Analyses of the Phase III Clinical Study Data

BACKGROUND

Despite a growing interest among men in cosmetic procedures such as botulinum toxin, comparator clinical trial data in this population are limited.

OBJECTIVES

The authors sought to compare the efficacy and safety of prabotulinumtoxinA and onabotulinumtoxinA for the treatment of males with moderate to severe glabellar lines.

METHODS

Post-hoc analyses were performed on the subpopulation of male patients treated with either a single dose of 20 U prabotulinumtoxinA (n = 25) or 20 U onabotulinumtoxinA (n = 31) in the EVB-003 Phase III glabellar line clinical study. One key efficacy endpoint was the proportion of responders with a ≥1-point improvement from baseline at maximum frown on the 4-point Glabellar Line Scale.

RESULTS

Compared with onabotulinumtoxinA-treated males, the percentages of responders who had a ≥1-point improvement on the Glabellar Line Scale at maximum frown were higher at all postbaseline time points for prabotulinumtoxinA-treated males (P > 0.05 at all visits) by an absolute overall mean difference of 10.1% across all visits. Similar trends were observed for efficacy endpoints based on global aesthetic improvement and subject satisfaction. PrabotulinumtoxinA-treated males had a higher incidence of treatment-related headache and eyelid ptosis.

CONCLUSIONS

The percentages of patients who met the definition of a responder were higher at almost all time points examined for prabotulinumtoxinA-treated males. Despite the high level of consistency across all measures, differences between the 2 treatment groups did not reach statistical significance. Further study is warranted to establish if these post-hoc analyses observations are reproducible in a larger male patient population.

LEVEL OF EVIDENCE: 1

Multicenter Study: Effectiveness and Efficiency of Prabotulinum Toxin-A Injection on Wrinkles in Forehead, Crow’s Feet, and Glabellar

BACKGROUND OF THE STUDY: Prabotulinumtoxin A (PRA) is the newest type A botulinum toxin produced by wild-type Clostridium botulinum. Prabotulinumtoxin A has a higher purity level than onabotulinum toxin A, but the literature discussing it is still limited and requires more research on its effectiveness. AIM OF THE STUDY: This research aimed to examine the efficacy of Prabotulinumtoxin A on wrinkles in forehead, crow’s feet and glabellar. METHODOLOGY: This research was a pre- and post-test, multicenter study from 3 center in Indonesia. Subjects will be observed at week 0, week 2, week 4, week 8 and week 12. Injection of prabotulinumtoxin A (INIBOÒ, Covaltt, South Korea) was performed intramuscularly on forehead, crow's feet, and glabellar with a dose of 4 IU / 0.1 ml. The measurement uses a scoring from the Upper Face Rating Scale. Different statistical test with repeated measurement test was conducted to compare the results between observations. The statistical test uses a confidence level of 0.95 with an error rate (α) = 0.05. RESULTS: The results of this study showed that Prabotulinumtoxin A injection was effective in reducing wrinkles in the frontal, glabellar and crow's feet area, with a statistically significant difference between week 0 and week 12. CONCLUSION: Prabotulinumtoxin A products improve the condition of wrinkles with a fairly good level of satisfaction and efficacy. Observations of more than 12 weeks are needed to determine the duration of Prabotulinumtoxin A products.

Immunogenicity of botulinum toxin

Botulinum toxin treatment is the most common non-surgical cosmetic treatment. Although there are many available treatments using botulinum toxin, their effects are temporary and repeated injections are required. These frequent injections can trigger an immunological response. In addition, botulinum toxin acts as an antigen in the body; thus, its effect disappears progressively due to this immunological reaction, which may cause treatment failure. Active botulinum toxin consists of a core neurotoxin and complexing proteins, the exact effects of which remain unclear. However, the complexing proteins are closely related to the immune response and the formation of neutralizing antibodies. Since neutralizing antibodies can lead to treatment failure, their formation should be prevented. Furthermore, various methods of detecting neutralizing antibodies have been used to predict treatment failure.

The First of Two One-Year, Multicenter, Open-Label, Repeat-Dose, Phase II Safety Studies of PrabotulinumtoxinA for the Treatment of Moderate to Severe Glabellar Lines in Adult Patients

Background

PrabotulinumtoxinA is a 900-kDa botulinum toxin type A produced by Clostridium botulinum.

Objectives

The authors sought to investigate the safety of prabotulinumtoxinA for treatment of glabellar lines.

Methods

This was a multicenter, open-label, repeat-dose, 1-year phase II safety study. Adults with moderate to severe glabellar lines at maximum frown, as assessed by the investigator on the validated 4-point photonumeric Glabellar Line Scale (0 = no lines, 1 = mild, 2 = moderate, 3 = severe), were enrolled. On day 0, patients received an initial treatment of 20 U prabotulinumtoxinA (4 U/0.1 mL freeze-dried formulation injected into 5 target glabellar sites). On and after day 90, patients received a repeat treatment (RT) if their Glabellar Line Scale score was ≥2 at maximum frown by investigator assessment. Safety was evaluated throughout the study.

Results

The 352 study patients received a median total dose of 60 U, that is, 3 treatments per year. Fifty-one patients (14.5%) experienced adverse events (AEs) assessed as possibly study drug related; 11.1% experienced study drug-related AEs after the initial treatment. With each RT, progressively lower percentages of patients experienced study drug-related AEs. Six patients (1.7%) experienced study drug-related AEs of special interest: 3 eyelid ptosis (0.9%), 2 speech disorder (0.6%), and 1 blepharospasm (0.3%). Seven patients (2.0%) experienced serious AEs; none were study drug related. Of the 2393 samples tested, 2 patients (0.6%) tested positive for antibotulinum toxin antibodies at a single postbaseline visit.

Conclusions

The safety of RTs of 20 U of prabotulinumtoxinA for moderate to severe glabellar lines was first established in this early phase II study based on a broad range of outcomes.

Level of Evidence: 2

The Second of Two One-Year, Multicenter, Open-Label, Repeat-Dose, Phase II Safety Studies of PrabotulinumtoxinA for the Treatment of Moderate to Severe Glabellar Lines in Adult Patients

BACKGROUND

PrabotulinumtoxinA is a 900-kDa botulinum toxin type A produced by Clostridium botulinum.

OBJECTIVES

The authors sought to investigate the safety of prabotulinumtoxinA for treatment of glabellar lines.

METHODS

This was a multicenter, open-label, repeat-dose, 1-year phase II safety study. Adults with moderate to severe glabellar lines at maximum frown, as independently assessed by both investigator and patient on the validated 4-point photonumeric Glabellar Line Scale (0 = no lines, 1 = mild, 2 = moderate, 3 = severe), were enrolled. On day 0, patients received an initial treatment (IT) of 20 U prabotulinumtoxinA (4 U/0.1 mL final vacuum-dried formulation injected into 5 glabellar sites). On and after day 90, patients received a repeat treatment (RT) if their Glabellar Line Scale score was ≥2 at maximum frown by investigator assessment. Safety outcomes were evaluated throughout the study.

RESULTS

The 570 study patients received a median total dose of 60 U, that is, 3 treatments. Sixty-one patients (10.7%) experienced adverse events (AEs) assessed as possibly study drug related; 6.5% experienced study drug-related AEs after the IT. With each RT, progressively lower percentages of patients experienced study drug-related AEs. Eight patients (1.4%) experienced study drug-related AEs of special interest: 5 experienced eyelid ptosis (0.9%), 3 eyebrow ptosis (0.5%), 1 blepharospasm (0.2%), and 1 blurred vision (0.2%). Seven patients (1.2%) experienced serious AEs, but none were study drug related. A total of 4060 serum samples were tested for antibotulinum toxin antibodies; no seroconversion was observed.

CONCLUSIONS

The safety of RTs of 20 U of prabotulinumtoxinA for moderate to severe glabellar lines was confirmed in this second phase II study based on a broad range of outcomes.

LEVEL OF EVIDENCE: 2

Therapeutic efficacy of new botulinum toxin identified in CCUG 7968 strain

Botulinum neurotoxin type A (BoNT/A) induces muscle atrophy by cleaving synaptosomal-associated protein 25. Thus, BoNT/A has been actively utilized for the treatment of masseter and gastrocnemius hypertrophy. In this study, INI101 toxin was newly identified from the CCUG 7968 strain, and its therapeutic efficacy was evaluated both in vitro and in vivo. The INI101 toxin showed identical genetic sequence, amino acid sequence, and protein subunit composition to BoNT/A produced from strain Hall A. Electromyography (EMG), and immunofluorescence staining demonstrated that INI101 (at 2 ~ 8 U/rat) effectively blocked the neuromuscular junction with no toxicity in a rat model. The EMG results showed INI101 toxin-induced weight loss and volume reduction of the gastrocnemius, similar to the effects of Botox® (BTX). Histological and immunofluorescence staining was consistent with this EMG result, showing that INI101 toxin caused muscle fiber reduction in the gastrocnemius. Notably, INI101 toxin diffused less into adjacent muscle tissue than BTX, indicating that INI101 toxin may reduce potential side effects due to diffusion into normal tissues. INI101 toxin isolated from the novel strain CCUG 7968 is a newly identified meaningful biopharmaceutical comparable to the conventional BoNT/A in the medical field. KEY POINTS: • Botulinum neurotoxin type A (BoNT/A, INI101) was identified from the CCUG 7968 strain. • INI101 toxin showed similar safety and therapeutic efficacy comparable to conventional BoNT/A both in vitro and in vivo. • INI101 toxin is a meaningful biopharmaceutical comparable to the conventional BoNT/A in the medical field.

Botulinum toxin type A for facial wrinkles

BACKGROUND

Botulinum toxin type A (BontA) is the most frequent treatment for facial wrinkles, but its effectiveness and safety have not previously been assessed in a Cochrane Review.

OBJECTIVES

To assess the effects of all commercially available botulinum toxin type A products for the treatment of any type of facial wrinkles.

SEARCH METHODS

We searched the following databases up to May 2020: the Cochrane Skin Specialised Register, CENTRAL, MEDLINE, Embase, and LILACS. We also searched five trials registers, and checked the reference lists of included studies for further references to relevant randomised controlled trials (RCTs).

SELECTION CRITERIA

We included RCTs with over 50 participants, comparing BontA versus placebo, other types of BontA, or fillers (hyaluronic acid), for treating facial wrinkles in adults.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Primary outcomes were participant assessment of success and major adverse events (AEs) (eyelid ptosis, eyelid sensory disorder, strabismus). Secondary outcomes included physician assessment of success; proportion of participants with at least one AE and duration of treatment effect. We used GRADE to assess the certainty of the evidence for each outcome.

MAIN RESULTS

We included 65 RCTs, involving 14,919 randomised participants. Most participants were female, aged 18 to 65 years. All participants were outpatients (private office or day clinic). Study duration was between one week and one year. No studies were assessed as low risk of bias in all domains; the overall risk of bias was unclear for most studies. The most common comparator was placebo (36 studies). An active control was used in 19 studies. There were eight dose-ranging studies of onabotulinumtoxinA, and a small number of studies compared against fillers. Treatment was given in one cycle (54 studies), two cycles (three studies), or three or more cycles (eight studies). The treated regions were glabella (43 studies), crow's feet (seven studies), forehead (two studies), perioral (two studies), full face (one study), or more than two regions (nine studies). Most studies analysed moderate to severe wrinkles; mean duration of treatment was 20 weeks. The following results summarise the main comparisons, based on studies of one treatment cycle for the glabella. AEs were collected over the duration of these studies (over four to 24 weeks). Compared to placebo, onabotulinumtoxinA-20 U probably has a higher success rate when assessed by participants (risk ratio (RR) 19.45, 95% confidence interval (CI) 8.60 to 43.99; 575 participants; 4 studies; moderate-certainty evidence) or physicians (RR 17.10, 95% CI 10.07 to 29.05; 1339 participants; 7 studies; moderate-certainty evidence) at week four. Major AEs are probably higher with onabotulinumtoxinA-20 U (Peto OR 3.62, 95% CI 1.50 to 8.74; 1390 participants; 8 studies; moderate-certainty evidence), but there may be no difference in any AEs (RR 1.14, 95% CI 0.89 to 1.45; 1388 participants; 8 studies; low-certainty evidence). Compared to placebo, abobotulinumtoxinA-50 U has a higher participant-assessed success rate at week four (RR 21.22, 95% CI 7.40 to 60.56; 915 participants; 6 studies; high-certainty evidence); and probably has a higher physician-assessed success rate (RR 14.93, 95% CI 8.09 to 27.55; 1059 participants; 7 studies; moderate-certainty evidence). There are probably more major AEs with abobotulinumtoxinA-50 U (Peto OR 3.36, 95% CI 0.88 to 12.87; 1294 participants; 7 studies; moderate-certainty evidence). Any AE may be more common with abobotulinumtoxinA-50 U (RR 1.25, 95% CI 1.05 to 1.49; 1471 participants; 8 studies; low-certainty evidence). Compared to placebo, incobotulinumtoxinA-20 U probably has a higher participant-assessed success rate at week four (RR 66.57, 95% CI 13.50 to 328.28; 547 participants; 2 studies; moderate-certainty evidence), and physician-assessed success rate (RR 134.62, 95% CI 19.05 to 951.45; 547 participants; 2 studies; moderate-certainty evidence). Major AEs were not observed (547 participants; 2 studies; moderate-certainty evidence). There may be no difference between groups in any AEs (RR 1.17, 95% CI 0.90 to 1.53; 547 participants; 2 studies; low-certainty evidence). AbobotulinumtoxinA-50 U is no different to onabotulinumtoxinA-20 U in participant-assessed success rate (RR 1.00, 95% CI 0.92 to 1.08, 388 participants, 1 study, high-certainty evidence) and physician-assessed success rate (RR 1.01, 95% CI 0.95 to 1.06; 388 participants; 1 study; high-certainty evidence) at week four. Major AEs are probably more likely in the abobotulinumtoxinA-50 U group than the onabotulinumtoxinA-20 U group (Peto OR 2.65, 95% CI 0.77 to 9.09; 433 participants; 1 study; moderate-certainty evidence). There is probably no difference in any AE (RR 1.02, 95% CI 0.67 to 1.54; 492 participants; 2 studies; moderate-certainty evidence). IncobotulinumtoxinA-24 U may be no different to onabotulinumtoxinA-24 U in physician-assessed success rate at week four (RR 1.01, 95% CI 0.96 to 1.05; 381 participants; 1 study; low-certainty evidence) (participant assessment was not measured). One participant reported ptosis with onabotulinumtoxinA, but we are uncertain of the risk of AEs (Peto OR 0.02, 95% CI 0.00 to 1.77; 381 participants; 1 study; very low-certainty evidence). Compared to placebo, daxibotulinumtoxinA-40 U probably has a higher participant-assessed success rate (RR 21.10, 95% CI 11.31 to 39.34; 683 participants; 2 studies; moderate-certainty evidence) and physician-assessed success rate (RR 23.40, 95% CI 12.56 to 43.61; 683 participants; 2 studies; moderate-certainty evidence) at week four. Major AEs were not observed (716 participants; 2 studies; moderate-certainty evidence). There may be an increase in any AE with daxibotulinumtoxinA compared to placebo (RR 2.23, 95% CI 1.46 to 3.40; 716 participants; 2 studies; moderate-certainty evidence). Major AEs reported were mainly ptosis; BontA is also known to carry a risk of strabismus or eyelid sensory disorders.

AUTHORS' CONCLUSIONS

BontA treatment reduces wrinkles within four weeks of treatment, but probably increases risk of ptosis. We found several heterogeneous studies (different types or doses of BontA, number of cycles, and different facial regions) hindering meta-analyses. The certainty of the evidence for effectiveness outcomes was high, low or moderate; for AEs, very low to moderate. Future RCTs should compare the most common BontA (onabotulinumtoxinA, abobotulinumtoxinA, incobotulinumtoxinA, daxibotulinumtoxinA, prabotulinumtoxinA) and evaluate long-term outcomes. There is a lack of evidence about the effects of multiple cycles of BontA, frequency of major AEs, duration of effect, efficacy of recently-approved BontA and comparisons with other treatments.

Efficacy and Safety of a New Botulinum Toxin (HU-014) Versus Existing Onabotulinumtoxin A in Subjects With Moderate to Severe Glabellar Lines

BACKGROUND

Recently, the safety of a new botulinum toxin (HU-014) was confirmed through animal experiments. The evaluation of the efficacy and safety of this newly introduced botulinum toxin is required considering the risk of adverse events (AEs) and need for standardization before its universal use.

OBJECTIVE

The aim of this multicenter, double-blind, randomized, parallel, active-controlled phase III clinical trial was to investigate the noninferiority of HU-014 versus existing onabotulinumtoxin A for the treatment of moderate to severe glabellar lines.

METHODS

In total, 267 subjects were randomized to either the test (HU-014) or control (onabotulinumtoxin A) group. At the baseline and at weeks 4, 8, 12, and 16, investigator's live assessment, independent photographic assessment, subjects' improvement assessment, subjects' satisfaction assessment, and safety assessment were performed.

RESULTS

At week 4, the response rate was 90.15% and 92.31% in the test and control groups, respectively, as per investigator's live assessment while frowning, without a significant difference. Both groups also showed no significant differences in response rates in the other assessments. In addition, no serious AEs were reported.

CONCLUSION

HU-014 was noninferior to existing onabotulinumtoxin A in the treatment of glabellar lines at a 1:1 dose ratio, and both products were well tolerated.

PrabotulinumtoxinA-xvfs for the Treatment of Moderate-to-Severe Glabellar Lines

OBJECTIVE

PrabotulinumtoxinA-xvfs (Jeuveau), a botulinum toxin type A, was approved by the Food and Drug Administration for the temporary improvement in the appearance of moderate-to-severe glabellar lines in February 2019. This article will review phase II and III clinical trials to assess the efficacy, safety, and clinical application of this novel, aesthetic-only drug.

DATA SOURCES

A systematic literature review was performed using the terms "glabellar lines AND prabotulinumtoxinA" in the PubMed database. ClinicalTrials.gov was searched to identify nonpublished studies.

STUDY SELECTION AND DATA EXTRACTION

Articles written in English between November 2019 and June 2020 discussing phase II and phase III clinical trials were evaluated.

DATA SYNTHESIS

By the primary efficacy end point on day 30, more patients achieved a greater than 2-point improvement on the Glabellar Line Scale (GLS) at maximum frown compared with baseline on day 0. The proportions of participants who responded to treatment with prabotulinumtoxinA were 67.5% and 70.4% versus 1.2% and 1.3% in placebo groups across 2 identical clinical trials (P < 0.001). Patients receiving prabotulinumtoxinA experienced greater improvement in GLS at maximum frown on day 30 (87.2%) compared with onabotulinumtoxinA (82.8%) and placebo (4.2%; P < 0.001). PrabotulinumtoxinA was well tolerated across all studies.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

This review provides a detailed analysis of the safety and efficacy of prabotulinumtoxinA-xvfs and includes special considerations to help guide patients and clinicians.

CONCLUSION

PrabotulinumtoxinA is a safe and effective new addition to the repository of available treatments for the appearance of glabellar lines.

OnabotulinumtoxinA Displays Greater Biological Activity Compared to IncobotulinumtoxinA, Demonstrating Non-Interchangeability in Both In Vitro and In Vivo Assays

Differences in botulinum neurotoxin manufacturing, formulation, and potency evaluation can impact dose and biological activity, which ultimately affect duration of action. The potency of different labeled vials of incobotulinumtoxinA (Xeomin^®; 50 U, 100 U, or 200 U vials; incobotA) versus onabotulinumtoxinA (BOTOX^®; 100 U vial; onabotA) were compared on a unit-to-unit basis to assess biological activity using in vitro (light-chain activity high-performance liquid chromatography (LCA-HPLC) and cell-based potency assay (CBPA)) and in vivo (rat compound muscle action potential (CMAP) and mouse digit abduction score (DAS)) assays. Using LCA-HPLC, incobotA units displayed approximately 54% of the protease activity of label-stated equivalent onabotA units. Lower potency, reflected by higher EC₅₀, ID₅₀, and ED₅₀ values (pooled mean ± SEM), was displayed by incobotA compared to onabotA in the CBPA (EC₅₀: incobotA 7.6 ± 0.7 U/mL; onabotA 5.9 ± 0.5 U/mL), CMAP (ID₅₀: incobotA 0.078 ± 0.005 U/rat; onabotA 0.053 ± 0.004 U/rat), and DAS (ED₅₀: incobotA 14.2 ± 0.5 U/kg; onabotA 8.7 ± 0.3 U/kg) assays. Lastly, in the DAS assay, onabotA had a longer duration of action compared to incobotA when dosed at label-stated equivalent units. In summary, onabotA consistently displayed greater biological activity than incobotA in two in vitro and two in vivo assays. Differences in the assay results do not support dose interchangeability between the two products.

Updates on Botulinum Neurotoxins in Dermatology

Being the most popular non-surgical cosmetic procedure, botulinum neurotoxin (BoNT) injections are increasingly of interest to all cosmetic practitioners across the globe. This article serves to update readers on the new botulinum toxins that are currently in development or close to market in the USA and Canada, including daxibotulinumtoxin A, prabotulinumtoxin A, letibotulinumtoxin A, and botulinum toxin E. Despite having relatively similar characteristics and equivalent clinical efficacies, these neurotoxins manifest a multitude of unique potential advantages that will be explored in this review, including but not limited to a longer duration of action, the absence of animal-derived components or human albumin, and a rapid onset with short duration of action.

A Multicenter, Randomized, Double-Blind, Placebo-Controlled, Single-Dose, Phase III, Non-Inferiority Study Comparing PrabotulinumtoxinA and OnabotulinumtoxinA for the Treatment of Moderate to Severe Glabellar Lines in Adult Patients

BACKGROUND

PrabotulinumtoxinA is a 900-kDa botulinum toxin type A produced by Clostridium botulinum.

OBJECTIVES

The authors sought to investigate the efficacy and safety of prabotulinumtoxinA compared to onabotulinumtoxinA and placebo for the treatment of glabellar lines.

METHODS

This was a 150-day, multicenter, double-blind, controlled, single-dose Phase III study. Adult patients (n = 540) with moderate to severe glabellar lines at maximum frown as assessed by the investigator on the validated 4-point Glabellar Line Scale (0 = no lines, 1 = mild, 2 = moderate, 3 = severe), who also felt that their glabellar lines had an important psychological impact, were enrolled. Patients were randomized 5:5:1 to receive a single treatment (0.1 mL injected into each of 5 glabellar sites) of 20 U prabotulinumtoxinA (n = 245), 20 U onabotulinumtoxinA (n = 246), or placebo (n = 49). The primary efficacy endpoint was the proportion of responders (patients with a Glabellar Line Scale score of 0 or 1 at maximum frown by investigator assessment) on day 30.

RESULTS

Responder rates for the primary efficacy endpoint were 87.2%, 82.8%, and 4.2% in the prabotulinumtoxinA, onabotulinumtoxinA, and placebo groups, respectively. The absolute difference between prabotulinumtoxinA and onabotulinumtoxinA groups was 4.4% (95% confidence interval [-1.9, 10.8]). Given that the lower bound of the 95% confidence interval for the difference was less than -10.0%, noninferiority of prabotulinumtoxinA vs onabotulinumtoxinA was concluded. Five patients (3 prabotulinumtoxinA, 1.2%; 1 onabotulinumtoxinA, 0.4%; 1 placebo, 2.0%) experienced serious adverse events, none of which were study drug related.

CONCLUSIONS

A single treatment of 20 U prabotulinumtoxinA was safe and effective and noninferior to 20 U onabotulinumtoxinA for the treatment of moderate to severe glabellar lines.

LEVEL OF EVIDENCE: 1

Efficacy and Safety of Prabotulinumtoxin A and Onabotulinumtoxin A for Crow's Feet: A Phase 3, Multicenter, Randomized, Double-Blind, Split-Face Study

BACKGROUND

Prabotulinumtoxin A has been shown to have efficacy for the treatment of upper-limb spasticity and improvement of moderate to severe glabellar lines. However, the efficacy and safety of prabotulinumtoxin A for crow's feet have not been evaluated.

OBJECTIVE

This study compared the efficacy and safety of prabotulinumtoxin A and onabotulinumtoxin A in the treatment of crow's feet.

PATIENTS AND METHODS

A multicenter, randomized, double-blind, active-controlled, split-face study was conducted in subjects with bilateral symmetric, moderate to severe crow's feet at maximum smile. The investigators assessed the severity of crow's feet by using the facial wrinkle scale, and the subjects reported the improvement in severity, their subjective satisfaction, and perceived age. The primary efficacy outcome was the proportion of subjects with Grade 0 or 1 severity of crow's feet at maximum smile at Week 4 as assessed by the investigators.

RESULTS

In the primary efficacy outcome assessment, there was no significant difference between the 2 groups (prabotulinumtoxin A, 65.02%; onabotulinumtoxin A, 62.56%; p = .0956). All secondary efficacy outcomes were also achieved. Adverse events related to injection were mild and recovered spontaneously.

CONCLUSION

Prabotulinumtoxin A and onabotulinumtoxin A have comparable efficacy and safety in the treatment of crow's feet.

Efficacy and Safety of PrabotulinumtoxinA for the Treatment of Glabellar Lines in Adult Subjects: Results From 2 Identical Phase III Studies

BACKGROUND

PrabotulinumtoxinA is a 900-kDa botulinum toxin Type A produced by Clostridium botulinum.

OBJECTIVE

To investigate the efficacy and safety of prabotulinumtoxinA for the treatment of glabellar lines.

MATERIALS AND METHODS

Adult subjects (n = 330 in EV-001; n = 324 in EV-002) with moderate to severe glabellar lines at maximum frown on the 4-point Glabellar Line Scale (GLS; 0 = no lines, 1 = mild, 2 = moderate, and 3 = severe) were enrolled in 1 of 2 identical 150-day, double-blind, placebo-controlled, single-dose, Phase III studies. Subjects were randomized 3:1 to receive 20-U prabotulinumtoxinA or placebo. The primary efficacy end point was the proportion of responders on Day 30 where the investigator and subject independently agreed that a ≥2-point improvement had occurred on the GLS at maximum frown from Day 0. Adverse events (AEs) were evaluated throughout the study.

RESULTS

Responder rates in the prabotulinumtoxinA and placebo groups were 67.5% and 1.2% in EV-001 and 70.4% and 1.3% in EV-002; absolute differences between groups were 66.3% and 69.1% in EV-001 and EV-002, respectively (both p < .001). No serious AE in either study was assessed as study drug related.

CONCLUSION

In these studies, a single dose of 20-U prabotulinumtoxinA was safe and effective for the treatment of glabellar lines.

Neurotoxin Impurities: A Review of Threats to Efficacy

Recently launched esthetic botulinum toxin serotype A (BoNT/A) products include Nabota/Jeuveau, Meditoxin/Neuronox, and Botulax, which contain nontoxic accessory proteins and excipients. Clinical evidence supporting these formulations, including their purity and potential immunogenicity or their link to treatment failures, is limited. Any nonhuman protein, including nontoxin accessory proteins, can initiate immune reactions, especially if administered repeatedly, yet the issue of BoNT/A-induced immunogenicity is widely contested. However, there have been multiple reports of treatment failures and observations of BoNT/A-induced neutralizing antibodies. Compared with the purified formulation in Xeomin, these recently launched toxins contain higher total neurotoxin quantities, much of which is inactive and exposes patients to potentially immunogenic nontoxin proteins or inactive neurotoxins that increase their risk of developing treatment failure. Well-established products [especially abobotulinumtoxinA (Dysport), onabotulinumtoxinA (Botox) and Xeomin] are accompanied by comprehensive and long-ranging clinical evidence on safety and efficacy in esthetic facial indications, which still remains undisclosed for many of the recently introduced toxins. Clinicians need this information as patients will require repeated BoNT treatments and may be unnecessarily but cumulatively exposed to potential immunogens. To underscore the need for caution and further evidence, we review some of the issues surrounding BoNT/A-induced immunogenicity and antibody-induced treatment failures and argue that using highly purified toxins that do not negatively impact patient outcomes is a prudent clinical decision.

Real-World Safety And Effectiveness Of OnabotulinumtoxinA Treatment Of Crow's Feet Lines And Glabellar Lines: Results Of A Korean Postmarketing Surveillance Study

Purpose

OnabotulinumtoxinA is approved in the Republic of Korea for the treatment of moderate-to-severe crow's feet lines (CFL) and glabellar lines (GL), separately or in combination. We assessed safety and effectiveness of onabotulinumtoxinA in real-world clinical practice.

Patient and methods

This 4-year postmarketing surveillance study was conducted in the Republic of Korea in subjects with moderate-to-severe CFL. Subjects aged 18 to 75 years received onabotulinumtoxinA injections for CFL alone or in combination with GL. Safety assessments included adverse events (AEs), serious AEs (SAEs), and unexpected AEs (not noted in Korean prescribing information). Investigators assessed effectiveness via change from baseline in CFL.

Results

The full analysis set comprised 695 subjects; 667 were in the safety set and 376 in the effectiveness set. In the safety set, mean ± SD age was 40.9±13.0 years; most subjects (87.3%) were female. More subjects were treated for CFL (69.9%) than CFL and GL simultaneously (30.1%). Eleven subjects experienced 14 AEs; 12 were mild in severity and 11 resolved without sequelae. Two cases of injection site pain in 2 subjects each were deemed possibly related to onabotulinumtoxinA. One unexpected SAE (acute renal failure) occurred in 1 subject (0.15%). All unexpected AEs (n=4) were mild and considered unrelated to treatment. Overall change from baseline showed CFL was improved in 375 subjects (99.7%) and unchanged in 1 subject (0.3%).

Conclusion

OnabotulinumtoxinA was well tolerated and effective for treatment of CFL with or without GL in a real-world Korean population. No new safety concerns were identified.

A comparison study of prabotulinumtoxinA vs onabotulinumtoxinA in myostatin-deficient mice with muscle hypertrophy

Botulinum toxin A (BoNT-A) is used clinically for various muscle disorders and acts by preventing the release of the neurotransmitter acetylcholine into the synapse space. Here, we compared the efficacy of prabotulinumtoxinA (PRA) and onabotulinumtoxinA (ONA) for the reduction in hypertrophy in myostatin-deficient (Mstn^-/- ) mice. Two different BoNT-A products (2.5, 10 and 25 U/kg) were injected to paralyse the hindlimb for 2 months, after which sciatic nerve conduction study, 3D micro-CT, haematoxylin and eosin (H&E) and dystrophin staining were conducted. Administration of BoNT-A products induced denervation-mediated atrophy and alleviated muscle hypertrophy generated in Mstn^-/- mice. The present study revealed that each BoNT-A regulates skeletal muscle size, myofibre number and myofibre diameter in Mstn^-/- mice. The potential applicability of BoNT-A for the treatment of rare muscle hypertrophic diseases was demonstrated. Compared with ONA, PRA had a comparable ability to act in the local area.

Safety, efficacy, and onset of a novel botulinum toxin type A (Nabota) for the treatment of glabellar frown lines: a single-arm, prospective, phase 4 clinical study

Background

Safety, efficacy, and time to onset of effect of botulinum toxin type A is of importance to persons who seek improvement in glabellar frown lines, but this has not been well studied. The aim of this study was to determine the safety, efficacy, and onset of action of a newly developed botulinum toxin type A (Nabota) for the treatment of glabellar frown lines.

Methods

This was a single-arm, open-label, and phase 4 clinical study. Forty-two subjects with glabellar lines were treated with five times of intramuscular injection of 0.1 mL (4 U/0.1 mL) for a total of 20 U of Nabota. Efficacy and safety were assessed at 2, 3, 4, 5, and 14 days. Efficacy was assessed by the investigator and it was defined as a 1-point change on a 4-point scale.

Results

Improvement in glabellar frown lines at maximum frown was observed in 85.4% of subjects 2 days after administration. Improvement in glabellar lines at rest was observed in 51.2% of subjects 2 days after administration, and the proportion of subjects showing improvement increased with time. No severe adverse events were recorded.

Conclusion

Onset of action was observed in the majority of subjects by 2 days after administration of Nabota. In addition, Nabota was found to be safe and effective for the treatment of glabellar frown lines.

Safety and Efficacy of PrabotulinumtoxinA (Nabota®) Injection for Cervical and Shoulder Girdle Myofascial Pain Syndrome: A Pilot Study

Myofascial pain syndrome is a common painful condition encountered in the general population. Previous studies evaluating the efficacy of botulinum toxin for the treatment of myofascial pain syndrome are limited, with variable results. This prospective study investigated the efficacy and safety of direct injection of Prabotulinumtoxin A (Nabota^®) into painful muscle groups for cervical and shoulder girdle myofascial pain. Twelve patients with chronic myofascial pain syndrome of the neck and shoulder underwent an injection of Prabotulinumtoxin A. Painful muscles containing trigger points were injected in the mid-belly. Pain scores and quality of life measurements were assessed at baseline, as well as 6 weeks and 12 weeks post-injection. Safety and tolerability were also assessed. This trial is registered under clinical research information service (CRIS) number KCT0001634. Patients injected with Prabotulinumtoxin A showed a significant improvement in pain at 12 weeks (p < 0.001). At 6 weeks, the pain had not significantly improved compared with baseline (p = 0.063). However, at that time, 41.7% of patients were characterized as Prabotulinumtoxin A responders, with a 30% reduction in pain rating score compared to baseline. In the Neck Disability Index scores, the patients demonstrated significant improvement at both 6 weeks and 12 weeks. No serious adverse effects occurred during the study. Prabotulinumtoxin A injection into chronically painful muscles associated with cervical and shoulder girdle myofascial pain syndrome resulted in an improvement in pain scores and quality of life lasting at least 12 weeks. Additionally, the injections were well tolerated. As these are preliminary findings in a pilot study, future studies should carefully consider using randomized, controlled, prospective trials.

The Effect of Intragastric Administration of Botulinum Toxin Type A on Reducing Adiposity in a Rat Model of Obesity Using Micro-CT and Histological Examinations

Background/Aims

Botulinum toxin type A (BTX), a long-acting inhibitor of muscular contraction in both striated and smooth muscles, is responsible for gastric motility. The aim of this study was to investigate the effects of an endoscopic intragastric BTX injection on weight loss, body fat accumulation, and gastric emptying time.

Methods

The BTX group consisted of 15 obese rats in which 20 U of BTX were injected into the gastric antrum. The saline group consisted of 15 obese rats injected with 20 U of saline, and the control group included 10 obese rats that did not receive a surgical intervention. The gastric emptying time, biochemical parameters, and body fat volume were evaluated using micro-computed tomography (micro-CT) and histologic evaluations.

Results

The postoperative body weight of the BTX group was significantly lower than those of the other groups (p<0.001) at 6 weeks after the operation. The gastric emptying time (156±54 minutes) was significantly delayed in the BTX group. The BTX group showed significantly lower lipid levels than the other groups. A reduction in body fat volume was observed in the BTX group using micro-CT and histological evaluations.

Conclusions

BTX application to the gastric antrum represents a potentially effective treatment for obesity and may help improve the lipid profile by increasing the gastric emptying time.

Efficacy and safety of NABOTA in post-stroke upper limb spasticity: a phase 3 multicenter, double-blinded, randomized controlled trial

Botulinum toxin A is widely used in the clinics to reduce spasticity and improve upper limb function for post-stroke patients. Efficacy and safety of a new botulinum toxin type A, NABOTA (DWP450) in post-stroke upper limb spasticity was evaluated in comparison with Botox (onabotulinum toxin A). A total of 197 patients with post-stroke upper limb spasticity were included in this study and randomly assigned to NABOTA group (n=99) or Botox group (n=98). Wrist flexors with modified Ashworth Scale (MAS) grade 2 or greater, and elbow flexors, thumb flexors and finger flexors with MAS 1 or greater were injected with either drug. The primary outcome was the change of wrist flexor MAS between baseline and 4weeks post-injection. MAS of each injected muscle, Disability Assessment Scale (DAS), and Caregiver Burden Scale were also assessed at baseline and 4, 8, and 12weeks after the injection. Global Assessment Scale (GAS) was evaluated on the last visit at 12weeks. The change of MAS for wrist flexor between baseline and 4weeks post-injection was -1.44±0.72 in the NABOTA group and -1.46±0.77 in the Botox group. The difference of change between both groups was 0.0129 (95% confidence interval -0.2062-0.2319), within the non-inferiority margin of 0.45. Both groups showed significant improvements regarding MAS of all injected muscles, DAS, and Caregiver Burden Scale at all follow-up periods. There were no significant differences in all secondary outcome measures between the two groups. NABOTA demonstrated non-inferior efficacy and safety for improving upper limb spasticity in stroke patients compared to Botox.