Pharmaceutical, biological, and clinical properties of botulinum neurotoxin type A products

Providing Optimal Rejuvenation to the Periocular Area Using Botulinum Toxin A Neuromodulators and Hyaluronic Acid Dermal Fillers

The periorbital area is the first area of the face to show signs of aging. To provide safe and natural looking rejuvenation of the delicate eyelids, and supporting structures, an advanced understanding of anatomy, ideal facial proportions, and the most effective methods for rejuvenation is discussed. Periocular rejuvenation is particularly challenging due to the intricate and delicate anatomy of the periocular area. To ensure safe and successful outcomes, it is crucial that injectors use a global approach when providing treatments and that they consider soft tissue, vasculature, and bone structure of the periocular region before administering treatments for aesthetic rejuvenation. Neuromodulators, specifically botulinum toxin A (BoNT-A), and hyaluronic acid (HA) dermal fillers are 2 nonsurgical treatments frequently used to address signs of aging in the periocular area. The objective of this article is to review different BoNT-A and HA filler treatments and discuss how these treatments can be used for optimal rejuvenation of the periocular area.

IncobotulinumtoxinA for the Treatment of Glabellar Frown Lines: A Prospective, Multicenter, Single-arm Study in Taiwan

Objective: We assessed clinical effectiveness, longevity of treatment effects, and patient satisfaction with incobotulinumtoxinA for glabellar frown lines (GFL) treatment in Asian patients. Design, Setting, and Participants: This was a prospective, multicenter, single-arm, open-label study at six sites in Taiwan. Patients aged 20 to 65 years with mild to very severe GFLs (Merz scale: 1-4 points) were eligible; 45 patients [including 23 BoNT/A-naïve and 22 previously-treated ("switch") patients were enrolled. Patients received intramuscular incobotulinumtoxinA injection at up to five injection points. Total doses ranged from 12 to 20U. Measurements: Investigators assessed improvements in dynamic GFLs at Days 14 and 120 using the validated five-point Merz scale (0=no lines; 4=very severe lines). Treatment satisfaction was self-reported by patients via questionnaire. Results: All patients showed excellent response to treatment in that Merz scores at Day 14 were 0 or 1 point(s). Both groups showed a mean improvement of 2.9 points; the response rate (1-point improvement or more from baseline) was 100 percent. GFL improvement was maintained over at least four months in both groups (mean improvements at Day 120: 1.5 points, naïve; 1.7 points, switch). Patient satisfaction ratings remained high (almost 100% in both groups) throughout the study. There were no statistically significant differences between groups regarding treatment satisfaction or GFL improvement (Merz score) at Days 14 and 120. No adverse events occurred. Conclusion: In Asian patients, incobotulinumtoxinA treatment for dynamic GFLs is effective and long lasting, with no expected differences between BoNT/A-naïve patients and those switching from other BoNT/As. IncobotulinumtoxinA yields consistent and natural-looking results for first and subsequent treatments.

Efficacy of electromotive drug administration in delivering botulinum toxin a in children with neuropathic detrusor overactivity-outcomes of a pilot study

BACKGROUND

Intravesical botulinum toxin A (BtA) injection is well established in managing paediatric neuropathic detrusor overactivity (NDO). Electromotive drug administration (EMDA) is a less invasive method, which can be performed in the clinic, using pulsed electrical current for drug delivery via a urethral catheter. Few small studies report good outcomes following BtA via EMDA (BtA/EMDA) into bladders of children with NDO.

OBJECTIVE

The objective of this study is to assess the efficacy of BtA/EMDA in children with NDO, reduced bladder capacity and compliance.

METHODS

Twelve children with NDO on baseline urodynamic study were prospectively included. Pre-BtA/EMDA and post-BtA/EMDA results compared the following four parameters: maximal cystometric capacity, bladder compliance, maximal detrusor pressure (pDetmax) during detrusor overactivity and pDetmax at capacity. The Wilcoxon matched-pairs signed-rank test using Graphpad Prism 8 was used for analysis. Secondary outcomes include adverse effects and symptomatic improvement.

RESULTS

Fourteen episodes of BtA/EMDA were performed. Five patients received 3.3 IU/kg of Botox®, and five received 10 IU/kg (maximum 300 IU). Four patients received 10 IU/kg of Dysport®. Two patients in the Dysport®/EMDA group also received Botox®/EMDA more than six months previously. Thirteen of 14 post-EMDA results were completed and included in the paired analysis. No statistically significant improvements in any cystometric parameters were demonstrated. Eight patients subsequently had intravesical BtA injections with significant improvements in both cystometric parameters and symptoms. Two patients subsequently transitioned to adult services; one was commenced on mirabegron, and one has undergone ileocystoplasty with Mitrofanoff appendicovesicostomy.

DISCUSSION

Despite some evidence to support BtA/EMDA in children with NDO, the authors were unable to replicate previously published positive cystometric and symptomatic outcomes. In addition, BtA/EMDA performed poorly when compared with conventional intravesical BtA injections. This implies failure of EMDA to deliver BtA correctly to the target tissue. The large size of the BtA molecule or the abnormal bladder wall in NDO could account for the negative results. Thorough preparation and consultation was undertaken before this study with BtA/EMDA, and it is discouraging that the authors were unable to reproduce the positive results of other groups.

CONCLUSIONS

Although safe and acceptable to most patients, the authors cannot recommend the use of BtA/EMDA for NDO in children at present.

In vitro quantification of botulinum neurotoxin type A1 using immobilized nerve cell-mimicking nanoreactors in a microfluidic platform

The bacterial toxin botulinum neurotoxin A (BoNT/A) is not only an extremely toxic substance but also a potent pharmaceutical compound that is used in a wide spectrum of neurological disorders and cosmetic applications. The quantification of the toxin is extremely challenging due to its extraordinary high physiological potency and is further complicated by the toxin's three key functionalities that are necessary for its activity: receptor binding, internalization-translocation, and catalytic activity. So far, the industrial standard to measure the active toxin has been the mouse bioassay (MBA) that is considered today as outdated due to ethical issues. Therefore, recent introductions of cell-based assays were highly anticipated; their impact however remains limited due to their labor-intensive implementation. This report describes a new in vitro approach that combines a nanosensor based on the use of nerve cell-mimicking nanoreactors (NMN) with microfluidic technology. The nanosensor was able to measure all three key functionalities, and therefore suitable to quantify the amount of physiologically active BoNT/A. The integration of such a sensor in a microfluidic device allowed the detection and quantification of BoNT/A amounts in a much shorter time than the MBA (<10 h vs. 2-4 days). Lastly, the system was also able to reliably quantify physiologically active BoNT/A within a simple final pharmaceutical formulation. This complete in vitro testing system and its unique combination of a highly sensitive nanosensor and microfluidic technology represent a significant ethical advancement over in vivo measures and a possible alternative to cell-based in vitro detection methods.

OnabotulinumtoxinA Wear-off Phenomenon in the Treatment of Chronic Migraine

OBJECTIVE

To evaluate the frequency and features of onabotulinumtoxinA (onabotA) wear-off in chronic migraine (CM).

BACKGROUND

Clinical experience suggests that patients with CM frequently perceive onabotA treatment duration <12 weeks, but this phenomenon has not been well explored.

METHODS

This study was a retrospective chart review of patients (n = 143) with CM initiated on onabotA over a 2-year period. Wear-off was considered present with the phrase documented, a quantitative headache day increase, or increased use of abortive medications, bridging therapies or emergency department visits in the 6 weeks preceding the subsequent administration.

RESULTS

Wear-off was present in 90/143 patients (62.9%). Age, sex, medication overuse, psychiatric comorbidity, injector training level, and mean days between injections did not differ between the wear-off and no wear-off groups. Mean units injected per session in the wear-off group until first documented wear-off were significantly less vs no wear-off group (166.0 ± 13.1 vs 173.4 ± 10.3, P = .0005). Wear-off most commonly occurred 2-4 weeks before the next injection (43.3%) and after the very first injection (40.0%). Intramuscular ketorolac injections (33.3%) and peripheral nerve blocks (25.6%) were the most common bridge therapies used in the wear-off period.

CONCLUSIONS

Most patients with CM receiving onabotA experience wear-off. Clinicians may consider increasing the units used from the treatment onset to reduce the frequent need for bridging therapies.

The role of human serum albumin and neurotoxin associated proteins in the formulation of BoNT/A products

Botulinum neurotoxin (BoNT) is synthesized as a progenitor toxin complex (PTC) by Clostridium botulinum. This PTC comprises, in addition to the neurotoxin itself, neurotoxin associated proteins (NAPs) which are composed of three hemagglutinins and one non-toxic, non-hemagglutinin protein. After oral ingestion, these NAPs protect the neurotoxin from the low pH and proteases in the gastrointestinal tract and play a role in the entry via the intestinal barrier. Two of the three therapeutically used botulinum neurotoxin serotype A (BoNT/A) products (onabotulinumtoxinA and abobotulinumtoxinA) contain different amounts of NAPs, while incobotulinumtoxinA, lacks these proteins. In addition, human serum albumin (HSA) that is supposed to stabilize BoNT/A is added at different concentrations. Up to now, the function of the NAPs and HSA after parenteral therapeutic application is not completely understood. To investigate the influence of NAPs and HSA on potency of BoNT/A, we used the ex vivo mouse phrenic nerve hemidiaphragm assay. Increasing doses of HSA resulted dose-dependently in a more pronounced effect of BoNT/A. Though, a plateau was reached with concentrations of 0.8 mg/ml HSA and higher, the accessory addition of NAPs in a relevant amount (4 ng/ml) did not further enhance the effect of BoNT/A. In conclusion, in our ex vivo assay an adequate concentration of HSA prevented BoNT/A from loss of effect and supplementary NAPs did not alter this effect. A confirmation of these data in an in vivo assay is still lacking. However, it might be supposed that even in clinically applied BoNT/A products an increase of HSA accompanied by the avoidance of NAPs could potentially reduce the injected dose and, thus, the risk of unwanted side effects, the treatment costs as well as the risk of a secondary therapy failure due to BoNT/A neutralizing antibodies.

Botulinum neurotoxin serotype D - A potential treatment alternative for BoNT/A and B non-responding patients

OBJECTIVES

Botulinum neurotoxin serotypes A and B (BoNT/A & B) are highly effective medicines to treat hyperactive cholinergic neurons. Due to neutralizing antibody formation, some patients may become non-responders. In these cases, the serotypes BoNT/C-G might become treatment alternatives. BoNT/D is genetically least related to BoNT/A & B and thereby circumventing neutralisation in A/B non-responders. We produced BoNT/D and compared its pharmacology with BoNT/A ex vivo in mice tissue and in vivo in human volunteers.

METHODS

BoNT/D was expressed recombinantly in E. coli, isolated by chromatography and its ex vivo potency was determined at mouse phrenic nerve hemidiaphragm preparations. Different doses of BoNT/D or incobotulinumtoxinA were injected into the extensor digitorum brevis (EDB) muscles (n = 30) of human volunteers. Their compound muscle action potentials were measured 11 times by electroneurography within 220 days.

RESULTS

Despite a 3.7-fold lower ex vivo potency in mice, a 110-fold higher dosage of BoNT/D achieved the same clinical effect as incobotulinumtoxinA while showing a 50% shortened duration of action.

CONCLUSIONS

BoNT/D blocks dose-dependently acetylcholine release in human motoneurons upon intramuscular administration, but its potency and duration of action is inferior to approved BoNT/A based drugs.

SIGNIFICANCE

BoNT/D constitutes a potential treatment alternative for BoNT/A & B non-responders.

Content/Potency Assessment of Botulinum Neurotoxin Type-A by Validated Liquid Chromatography Methods and Bioassays

Botulinum neurotoxin type-A (BoNTA) is one of the seven different serotypes (A to G) produced by Clostridium botulinum. A stability-indicating size-exclusion chromatography (SEC) method was developed and validated, and the specificity was confirmed by forced degradation study, interference of the excipients, and peaks purity. The method was applied to assess the content and high-molecular-weight (HMW) forms of BoNTA in biopharmaceutical products, and the results were compared with those of the LD₅₀ mouse bioassay, the T−47D cell culture assay, and the reversed-phase chromatography (RPC) method, giving mean values of 0.71% higher, 0.36% lower, and 0.87% higher, respectively. Aggregated forms showed significant effects on cytotoxicity, as well as a decrease in the bioactivity (p < 0.05). The employment of the proposed method in conjunction with the optimized analytical technologies for the analysis of the intact and altered forms of the biotechnology-derived medicines, in the correlation studies, enabled the demonstration of the capability of each one of the methods and allowed for great improvements, thereby assuring their safe and effective use.

In silico mutagenesis: decreasing the immunogenicity of botulinum toxin type A

Botulinum toxin serotype A is a prominent therapeutic enzyme, for both clinical and cosmetic uses. Since this protein is produced by bacteria, it exhibits an allergenic effect when subjected to human therapy. Protein mutagenesis is one method to improve the characteristics of protein. However, in silico study is needed to give suggestion of which amino acid should be mutated. Hence, a lot of money and time can be saved. This study initially screened which residue of the Botulinum toxin serotype A is B-cell epitopes both linearly and conformationally. By overlapping the B-cell epitopes with the excluded conserve sequence, seven residues were allowed to be mutated. There were two proposed muteins showing a reduction in the antigenicity probability: ΔE147, E510F, T1062F, ΔE1080, N1089M and ΔQ1090; and ΔE147, E510F, T1062F, E1080W, N1089M and ΔQ1090. Molecular dynamics simulation of the 3D proposed muteins indicated an increase of flexibility in both muteins compared to that in the native protein. Both muteins have lower antigenicity. In addition, they are similar in structure, stability and functionality compared to the native protein.

High prevalence of neutralizing antibodies after long-term botulinum neurotoxin therapy

Objective

To investigate the prevalence of neutralizing antibodies (NAbs) against botulinum neurotoxin type A (BoNT/A) during long-term BoNT/A treatment in different neurologic indications.

Methods

In this monocentric, observational cross-sectional study, 596 outpatients treated with BoNT/A for different indications were tested for BoNT/A binding antibodies by ELISA. Positive samples were investigated for NAbs with the mouse hemidiaphragm test. The prevalence of NAbs was analyzed for different indications: facial hemispasm, blepharospasm, cervical dystonia, other dystonia, and spasticity. Besides the rate of NAb-positive patients overall and per patient subgroup, a Kaplan-Meier analysis of the probability of remaining NAb negative with duration of treatment is provided, and a stepwise binary logistic regression analysis is performed to identify factors significantly contributing to the induction of NAbs.

Results

Overall, 83 of 596 patients (13.9%) had measurable NAbs. The probability of developing NAbs increased with the single and cumulative dose of treatment and was influenced by the BoNT/A formulation, while all other factors analyzed, including disease entity and treatment duration, had no additional influence.

Conclusions

We present the largest study to date of the prevalence of BoNT/A NAbs in a large unbiased cohort of patients including the relevant neurologic indications. Repeated injections of BoNT/A inevitably bear the risk of developing NAbs. However, in addition to avoiding booster injections and providing short intervals between injections, reducing the individual injected doses may diminish the risk of NAb induction independently of the indication for which BoNT/A is used.

AbobotulinumtoxinA for the treatment of overactive bladder

INTRODUCTION

Overactive bladder is a common condition that can have a negative impact on quality of life. Botulinum Toxin A is a third line treatment for overactive bladder following conservative measures and anticholinergic medication. At present, OnabotulinumtoxinA is the only preparation licensed for this indication. More recently, trials have been undertaken to compare the efficacy of this to AbobotulinumtoxinA. Areas covered: This article aims to provide an overview of AbobotulinumtoxinA, which is currently not yet licensed for overactive bladder or neurogenic detrusor overactivity. It will detail the pharmacokinetics and dynamics, assess the available clinical trial data and make comparisons with current clinical practice. A systematic literature search was completed, using ovid Medline and Embase, with the aim to review all data concerning the administration of AbobotulinumtoxinA for the treatment of overactive bladder. Expert opinion: Currently, there are a lack of data on the use of AbobotulinumtoxinA for overactive bladder or neurogenic detrusor overactivity. Current evidence concentrates on its use in neurogenic detrusor overactivity, and there are data to show it may be as efficacious as OnabotulinumtoxinA. However, there is a lack of homogenous data to compare the two products and therefore we are unable to recommend this currently.

Botulinum neurotoxin formulations: overcoming the confusion

Botulinum toxin A is produced by anaerobic spore-forming bacteria and is used for various therapeutic and cosmetic purposes. Botulinum toxin A injections are the most popular nonsurgical procedure worldwide. Despite an increased demand for botulinum toxin A injections, the clinical pharmacology and differences in formulation of commonly available products are poorly understood. The various products available in the market are unique and vary in terms of units, chemical properties, biological activities, and weight, and are therefore not interchangeable. For safe clinical practice and to achieve optimal results, the practitioners need to understand the clinical issues of potency, conversion ratio, and safety issues (toxin spread and immunogenicity). In this paper, the basic clinical pharmacology of botulinum toxin A and differences between onabotulinum toxin A, abobotulinum toxin A, and incobotulinum toxin A are discussed.

Assessing adverse effects of intra-articular botulinum toxin A in healthy Beagle dogs: A placebo-controlled, blinded, randomized trial

OBJECTIVE

To investigate the clinical, cytological, and histopathological adverse effects of intra-articularly injected botulinum toxin A in dogs and to study whether the toxin spreads from the joint after the injection.

METHODS

A longitudinal, placebo-controlled, randomized clinical trial was conducted with six healthy laboratory Beagle dogs. Stifle joints were randomized to receive either 30 IU of onabotulinum toxin A or placebo in a 1:1 ratio. Adverse effects and spread of the toxin were examined by evaluating dynamic and static weight-bearing of the injected limbs, by assessing painless range of motion and pain on palpation of joints, and by performing synovial fluid analysis, neurological examination, and electrophysiological recordings at different examination time-points in a 12-week period after the injections. The dogs were then euthanized and autopsy and histopathological examination of joint structures and adjacent muscles and nerves were performed.

RESULTS

Intra-articular botulinum toxin A did not cause local weakness or injection site pain. Instead, static weight-bearing and painless range of motion of stifle joints decreased in the placebo limbs. No clinically significant abnormalities associated with intra-articular botulinum toxin A were detected in the neurological examinations. Electrophysiological recordings showed low compound muscle action potentials in two dogs in the botulinum toxin A-injected limb. No significant changes were detected in the synovial fluid. Autopsy and histopathological examination of the joint and adjacent muscles and nerves did not reveal histopathological adverse effects of the toxin.

CONCLUSION

Intra-articular botulinum toxin A does not produce significant clinical, cytological, or histopathological adverse effects in healthy dogs. Based on the electrophysiological recordings, the toxin may spread from the joint, but its clinical impact seems to be low.

Therapeutic uses and efficacy of botulinum toxin in orofacial medicine

Introduction: Botulinum toxin, primarily known for its use in cosmetic surgery, is also used for therapeutic purposes in many medical fields. It works as a muscle relaxant and inhibits glandular secretions. In the orofacial sphere, the use of this toxin is proposed in particular for disabling myofascial pain and aberrant salivary disorders. Methodology: A critical analysis of the literature, based on PUBMED data, concerning the orofacial indications of botulinum toxin was carried out. Results: The literature is abundant regarding the therapeutic interest of this toxin for several oral pathologies, but scientific merits vary markedly from one indication to another. Discussion: The musculorelaxant and antisecretory action of this toxin appears to be demonstrated in the case of bruxism, limitation of the mouth opening and in hypersialorrhea. On the other hand, its medical benefit is still not supported by scientific evidence for masseter hypertrophy, tonicity of the levator labii superioris muscles, sialocele fistulae and Frey's syndrome. Conclusion: Additional high-level studies, unbiased, randomized controlled trials, are required to eliminate the uncertainties that persist about the clinical impact of botulinum toxin and to justify the development of recommendations for good practice valid and credible.

The Use of Botulinum Neurotoxin Type A in Aesthetics: Key Clinical Postulates

BACKGROUND

The most common aesthetic procedure performed worldwide is the injection of botulinum neurotoxin Type A (BoNT-A). Aesthetic providers must fully comprehend the objective scientific data, theoretical mechanisms of action, and differences between brands of BoNT-A.

OBJECTIVE

To determine and review the relevant clinical postulates for the use of botulinum toxin in aesthetics.

MATERIALS AND METHODS

The BoNT-A clinical postulates presented here discuss how each brand of BoNT-A acts identically, how the molecular potency may vary between the different products, how patient age, gender, genetics, and muscle mass cause variation in toxin receptor number and density, and how both practitioner and patient can affect toxin distribution.

RESULTS

A total of 8 clinical postulates have been identified that are key to understanding the use of botulinum toxin in aesthetics and to obtaining the best clinical results.

CONCLUSION

All of these factors affect the potential efficacy of the injected toxin and hence the aesthetic results obtained.

[Conversion ratio between different botulinum neuroprotein product in neurological practice]

Despite nearly 30 years of experience in the application of botulinum toxin type A (BTA) in clinical practice, many fundamental questions of therapy remain valid. There are 5 botulinum toxin type A used for neurological indications in the Russian Federation in 2017. They contain different number of active neuroprotein (150 kDa) in a therapeutic dose of the drug that may have a potential impact on the efficacy and duration of action. The current SmPC of each BTA stated that the unit of activity is unique and can not be compared with any other BTA. In scientific publications one can find many details concerning the equivalence doses of onabotulinumtoxin A (botox) and abobotulinumtoxin A (dysport) and the ratio of units varies from 1:1 to 1:11. However, according to clinical guidelines, systematic reviews and high quality research evidence of recent years, the ratio of units of abobotulinumtoxin A (dysport) and onabotulinumtoxin A (botox) is 3(2,5):1. Use of a fixed ratio of units is possible only when switching from one drug to another or in case of limiting access to specific drug. Botulinum toxin type A is the first line of therapy in the treatment of several neurological diseases. The most commonly used drugs of botulinum toxin type A (botox, dysport, xeomin) have a significant evidence base that confirms their efficacy and optimal safety profile. The main difference between botulinum toxin type A is their potential activity of action, i.e., activity units and total therapeutic dose.

Efficacy and Tolerability of IncobotulinumtoxinA for Treating Glabellar Frown Lines in Korean Adults: A Postmarketing Observational Study

BACKGROUND

IncobotulinumtoxinA is safe and effective in Caucasian adults. Its effects have been less documented in Asian adults.

OBJECTIVE

To describe the efficacy and tolerability of incobotulinumtoxinA for treating glabellar frown lines (GFLs) in South Korean adults.

METHODS

South Korean adults aged 18 to 65 years with moderate-to-severe GFLs received a single dose of 10 to 28 U incobotulinumtoxinA during routine clinical practice. After 30 ± 14 days, investigators assessed the efficacy using the Global Aesthetic Improvement Scale and rated tolerability using a 4-point scale.

RESULTS

Six hundred seventy-three subjects were enrolled, of which 528 completed the study according to protocol. Glabellar frown lines improved in 98.7% (521/528) of subjects, with 30.8% of cases rated as "very much improved" and 47.4% as "much improved." The extent of improvement was unaffected by sex, age, and weight but was greater when the time between GFL identification and treatment was <6 months (p < .001) and when concomitant aesthetic nondrug treatments were used (p < .001). For 94% of subjects, tolerability was good or very good. All reported adverse events were transient and mild or moderate in severity.

CONCLUSION

IncobotulinumtoxinA was well tolerated and effective for treating moderate-to-severe GFLs in Korean adults irrespective of age, sex, or weight.

Design of modified botulinum neurotoxin A1 variants with a shorter persistence of paralysis and duration of action

Botulinum neurotoxins (BoNTs) are classified by their antigenic properties into seven serotypes (A-G) and in addition by their corresponding subtypes. They are further characterized by divergent onset and duration of effect. Injections of low doses of botulinum neurotoxins cause localized muscle paralysis that is beneficial for the treatment of several medical disorders and aesthetic indications. Optimizing the therapeutic properties could offer new treatment opportunities. This report describes a rational design approach to modify the pharmacological properties by mutations in the C-terminus of BoNT/A1 light chain (LC). Toxins with C-terminal modified LC's displayed an altered onset and duration of the paralytic effect in vivo. The level of effect was dependent on the kind of the mutation in the sequence of the C-terminus. A mutant with three mutations (T420E F423M Y426F) revealed a faster onset and a shorter duration than BoNT/A1 wild type (WT). It could be shown that the C-terminus of BoNT/A1-Lc controls both onset and duration of effect. Thus, it is possible to create a mutated BoNT/A1 with different pharmacological properties which might be useful in the therapy of new indications. This strategy opens the way to design BoNT variants with novel and useful properties.

Treatment of Lateral Periorbital Lines with Different Dilutions of IncobotulinumtoxinA

BACKGROUND: IncobotulinumtoxinA is a botulinum neurotoxin type A that is free from complexing proteins and is used in various therapeutic indications and aesthetic medicine. It is approved for the treatment of glabellar frown lines in the United States. In Europe, it is also approved for the treatment of lateral periorbital lines (crow's feet) and for the combined treatment of upper facial lines, including glabellar frown lines, crow's feet, and horizontal forehead lines. METHODS: In the present study, incobotulinumtoxinA was injected at two different dilutions to treat female subjects aged 40 to 50 years who had moderate-to-severe lateral periorbital lines at maximum contraction according to a score of 2 or 3 points on the 5-point Merz Aesthetics Scales (MAS). For Group 1 (n=20), 50U of incobotulinumtoxinA were reconstituted with 1.60mL of 0.9% NaCI, and for Group 2 (n=20), a reconstitution volume of 0.55mL was used. RESULTS: Merz Aesthetics Scales scores were markedly improved by at least one point in both groups at one month and three months. The mean Merz Aesthetics Scales scores at one month were 0.4 and 0.6 points for Group 1 and Group 2, respectively, corresponding to a mean improvement of 2.0 and 1.8 points compared with baseline, respectively. CONCLUSION: No significant differences in efficacy and tolerability of incobotulinumtoxinA were seen between the two dilutions at any time point.

IncobotulinumtoxinA for Aesthetic Indications: A Systematic Review of Prospective Comparative Trials

BACKGROUND

IncobotulinumtoxinA is a botulinum toxin type A (BoNTA) indicated for temporary improvement in the appearance of upper facial lines with well-established efficacy and safety profiles. Whether incobotulinumtoxinA and other BoNTAs are equipotent is subject of debate.

OBJECTIVE

To compare the efficacy of incobotulinumtoxinA and other BoNTAs for aesthetic applications.

MATERIALS AND METHODS

PubMed and Embase were systematically searched for prospective clinical trials comparing incobotulinumtoxinA with onabotulinumtoxinA, abobotulinumtoxinA, or placebo for aesthetic applications.

RESULTS

Fifteen articles met the selection criteria. Two studies found that incobotulinumtoxinA was noninferior or equivalent to onabotulinumtoxinA for the treatment of glabellar frown lines (GFLs). Eight studies found no difference in efficacy between incobotulinumtoxinA and other BoNTAs. One study suggested differences in response rates at certain time points between incobotulinumtoxinA and onabotulinumtoxinA for GFLs, and one suggested differences for dynamic horizontal forehead lines but not for GFLs or lateral periorbital lines, but both had study design issues limiting the ability to draw conclusions. Finally, 3 placebo-controlled studies demonstrated the efficacy of incobotulinumtoxinA for treating GFLs and upper facial lines.

CONCLUSION

The weight of the evidence from comparative clinical trials indicates that incobotulinumtoxinA, onabotulinumtoxinA, and abobotulinumtoxinA have similar efficacy for aesthetic applications.

Botulinum Neurotoxins: Biology, Pharmacology, and Toxicology

The study of botulinum neurotoxins (BoNT) is rapidly progressing in many aspects. Novel BoNTs are being discovered owing to next generation sequencing, but their biologic and pharmacological properties remain largely unknown. The molecular structure of the large protein complexes that the toxin forms with accessory proteins, which are included in some BoNT type A1 and B1 pharmacological preparations, have been determined. By far the largest effort has been dedicated to the testing and validation of BoNTs as therapeutic agents in an ever increasing number of applications, including pain therapy. BoNT type A1 has been also exploited in a variety of cosmetic treatments, alone or in combination with other agents, and this specific market has reached the size of the one dedicated to the treatment of medical syndromes. The pharmacological properties and mode of action of BoNTs have shed light on general principles of neuronal transport and protein-protein interactions and are stimulating basic science studies. Moreover, the wide array of BoNTs discovered and to be discovered and the production of recombinant BoNTs endowed with specific properties suggest novel uses in therapeutics with increasing disease/symptom specifity. These recent developments are reviewed here to provide an updated picture of the biologic mechanism of action of BoNTs, of their increasing use in pharmacology and in cosmetics, and of their toxicology.

Key Parameters for the Use of AbobotulinumtoxinA in Aesthetics: Onset and Duration

Time to onset of response and duration of response are key measures of botulinum toxin efficacy that have a considerable influence on patient satisfaction with aesthetic treatment. However, there is no overall accepted definition of efficacy for aesthetic uses of botulinumtoxinA (BoNT-A). Mechanical methods of assessment do not lend themselves to clinical practice and clinicians rely instead on assessment scales such as the Frontalis Activity Measurement Standard, Frontalis Rating Scale, Wrinkle Severity Scale, and Subject Global Assessment Scale, but not all of these have been fully validated. Onset of activity is typically seen within 5 days of injection, but has also been recorded within 12 hours with abobotulinumtoxinA. Duration of effect is more variable, and is influenced by parameters such as muscle mass (including the effects of age and sex) and type of product used. Even when larger muscles are treated with higher doses of BoNT-A, the duration of effect is still shorter than that for smaller muscles. Muscle injection technique, including dilution of the toxin, the volume of solution injected, and the positioning of the injections, can also have an important influence on onset and duration of activity. Comparison of the efficacy of different forms of BoNT-A must be made with the full understanding that the dosing units are not equivalent. Range of equivalence studies for abobotulinumtoxinA (Azzalure; Ipsen Limited, Slough UK/Galderma, Lausanne CH/Dysport, Ipsen Biopharm Limited, Wrexham UK/Galderma LP, Fort Worth, TX) and onabotulinumtoxinA (Botox; Allergan, Parsippany, NJ) have been conducted, and results indicate that the number of units of abobotulinumtoxinA needs to be approximately twice as high as that of onabotulinumtoxinA to achieve the same effect. An appreciation of the potential influence of all of the parameters that influence onset and duration of activity of BoNT-A, along with a thorough understanding of the anatomy of the face and potency of doses, are essential to tailoring treatment to individual patient needs and expectations.

Safety and Patient Satisfaction of AbobotulinumtoxinA for Aesthetic Use: A Systematic Review

A systematic review of the published literature (from January 2000 to January 2016) to ascertain the safety of, and patient satisfaction with, the aesthetic use of abobotulinumtoxinA was conducted. In addition to the licensed indications, other special populations were considered for discussion. The potential impact of neutralizing antibodies and systemic toxicity were also addressed. A total of 364 papers were screened and 86 were found to be relevant to the population, intervention(s), and outcomes stipulated in the protocol. The safety and patient satisfaction data from these publications are discussed in this review.

Switch to Abobotulinum toxin A may be useful in the treatment of neurogenic detrusor overactivity when intradetrusor injections of Onabotulinum toxin A failed

AIMS

To assess the outcomes of switching to a different brand of botulinum toxin A (BTA, from Botox® to Dysport®) in case of failure of intradetrusor injections (IDI) of Botox® in the treatment of neurogenic detrusor overactivity (NDO).

METHODS

The charts of all patients who underwent a switch to IDI of Dysport® after failure of an IDI of Botox® at six departments of neurourology were retrospectively reviewed. The main outcomes of interest were the bladder diary data and four urodynamic parameters: maximum cystometric capacity (MCC), maximum detrusor pressure (PDET max), and volume at first uninhibited detrusor contraction (UDC).

RESULTS

Fifty-seven patients were included. After the first injection of Dysport®, no adverse events were reported. A significant decrease in number of urinary incontinence episodes per day was observed in 52.63% of patients (P < 0.001) and all patients experienced a reduction in PDET Max (-8.1 cmH20 on average; P = 0.003). MCC significantly increased by a mean of 41.2 (P = 0.02). The proportion of patients with no UDC increased significantly at week 6 after ATA injections (from 15.79% to 43.9%; P = 0.0002). Hence, 32 patients draw clinical and/or urodynamic benefits from the botulinum toxin switch from (56.14%). After a median follow up of 21 months, 87% of responders to BTA switch were still treated successfully with BTA.

CONCLUSION

Most patients refractory to Botox® (56.14%) draw benefits from the switch to Dysport®.

Consensus Recommendations for Combined Aesthetic Interventions in the Face Using Botulinum Toxin, Fillers, and Energy-Based Devices

BACKGROUND

The aging process is a complex interplay of intrinsic and extrinsic factors across multiple layers of the face. Accordingly, combining aesthetic interventions targeting different manifestations of aging often leads to better results than single modalities alone. However, no guidelines for a pan-facial approach using multiple interventions have been published to date.

OBJECTIVE

To develop consensus recommendations for the optimal combination and ideal sequence of botulinum toxin (BoNT), hyaluronic acid, calcium hydroxylapatite, and microfocused ultrasound with visualization (MFU-V) in persons of all Fitzpatrick skin types.

METHODS AND MATERIALS

Fifteen specialists convened under the guidance of a certified moderator. Consensus was defined as approval from 75% to 94% of all participants, whereas agreement of ≥95% denoted a strong consensus.

RESULTS

Optimal aesthetic treatment of the face begins with a thorough patient assessment and an individualized treatment plan. Spacing consecutive treatments 1 to 2 weeks apart allows for resolution of side effects and/or to assess results. For same-day treatments, BoNT and fillers may be performed together in either sequence, whereas MFU-V is recommended before injectable agents.

CONCLUSION

Expert consensus supports a combination approach using multiple modalities in specific sequence for the safe and effective treatment of the aging face.

Conversion Ratio between Botox®, Dysport®, and Xeomin® in Clinical Practice

Botulinum neurotoxin has revolutionized the treatment of spasticity and is now administered worldwide. There are currently three leading botulinum neurotoxin type A products available in the Western Hemisphere: onabotulinum toxin-A (ONA) Botox(®), abobotulinum toxin-A (ABO), Dysport(®), and incobotulinum toxin A (INCO, Xeomin(®)). Although the efficacies are similar, there is an intense debate regarding the comparability of various preparations. Here we will address the clinical issues of potency and conversion ratios, as well as safety issues such as toxin spread and immunogenicity, to provide guidance for BoNT-A use in clinical practice. INCO was shown to be as effective as ONA with a comparable adverse event profile when a clinical conversion ratio of 1:1 was used. The available clinical and preclinical data suggest that a conversion ratio ABO:ONA of 3:1-or even lower-could be appropriate for treating spasticity, cervical dystonia, and blepharospasm or hemifacial spasm. A higher conversion ratio may lead to an overdosing of ABO. While uncommon, distant spread may occur; however, several factors other than the pharmaceutical preparation are thought to affect spread. Finally, whereas the three products have similar efficacy when properly dosed, ABO has a better cost-efficacy profile.

A Randomized, Double-Blind Trial to Investigate the Equivalence of IncobotulinumtoxinA and OnabotulinumtoxinA for Glabellar Frown Lines

BACKGROUND

IncobotulinumtoxinA and onabotulinumtoxinA are indicated for the temporary improvement in the appearance of glabellar frown lines (GFL). This is the first randomized direct comparator study to date, at the Food and Drug Administration-recommended dose of 20 units (U), for the treatment of GFL.

OBJECTIVE

To investigate the dose equivalence of incobotulinumtoxinA (20 U) and onabotulinumtoxinA (20 U) for the treatment of moderate-to-severe GFL.

MATERIALS AND METHODS

Prospective, randomized (1:1), double-blinded, parallel-group study in 250 females (18-50 years), employing a single treatment with incobotulinumtoxinA or onabotulinumtoxinA, followed by a 4-month observational period.

RESULTS

At the primary efficacy endpoint (1 month after treatment), incobotulinumtoxinA was equivalent to onabotulinumtoxinA in the treatment of GFL at the 20 U dose within the prespecified ± 15% margin of equivalence. Efficacy remained similar between treatment groups through 4 months after treatment as assessed by the independent masked panel and the masked treating physicians. Patient satisfaction ratings were similar between groups and favorable (>90%) throughout. Both treatments were well tolerated.

CONCLUSION

Equivalence was demonstrated at the primary endpoint between incobotulinumtoxinA and onabotulinumtoxinA in the treatment of GFL at the 20 U dose at 1 month. Similar efficacy and tolerability profiles were observed through 4 months after treatment.

Generation and Characterization of Six Recombinant Botulinum Neurotoxins as Reference Material to Serve in an International Proficiency Test

The detection and identification of botulinum neurotoxins (BoNT) is complex due to the existence of seven serotypes, derived mosaic toxins and more than 40 subtypes. Expert laboratories currently use different technical approaches to detect, identify and quantify BoNT, but due to the lack of (certified) reference materials, analytical results can hardly be compared. In this study, the six BoNT/A1–F1 prototypes were successfully produced by recombinant techniques, facilitating handling, as well as improving purity, yield, reproducibility and biosafety. All six BoNTs were quantitatively nicked into active di-chain toxins linked by a disulfide bridge. The materials were thoroughly characterized with respect to purity, identity, protein concentration, catalytic and biological activities. For BoNT/A₁, B₁ and E₁, serotypes pathogenic to humans, the catalytic activity and the precise protein concentration were determined by Endopep-mass spectrometry and validated amino acid analysis, respectively. In addition, BoNT/A₁, B₁, E₁ and F₁ were successfully detected by immunological assays, unambiguously identified by mass spectrometric-based methods, and their specific activities were assigned by the mouse LD₅₀ bioassay. The potencies of all six BoNT/A1–F1 were quantified by the ex vivo mouse phrenic nerve hemidiaphragm assay, allowing a direct comparison. In conclusion, highly pure recombinant BoNT reference materials were produced, thoroughly characterized and employed as spiking material in a worldwide BoNT proficiency test organized by the EQuATox consortium.

Recommended Immunological Strategies to Screen for Botulinum Neurotoxin-Containing Samples

Botulinum neurotoxins (BoNTs) cause the life-threatening neurological illness botulism in humans and animals and are divided into seven serotypes (BoNT/A–G), of which serotypes A, B, E, and F cause the disease in humans. BoNTs are classified as “category A” bioterrorism threat agents and are relevant in the context of the Biological Weapons Convention. An international proficiency test (PT) was conducted to evaluate detection, quantification and discrimination capabilities of 23 expert laboratories from the health, food and security areas. Here we describe three immunological strategies that proved to be successful for the detection and quantification of BoNT/A, B, and E considering the restricted sample volume (1 mL) distributed. To analyze the samples qualitatively and quantitatively, the first strategy was based on sensitive immunoenzymatic and immunochromatographic assays for fast qualitative and quantitative analyses. In the second approach, a bead-based suspension array was used for screening followed by conventional ELISA for quantification. In the third approach, an ELISA plate format assay was used for serotype specific immunodetection of BoNT-cleaved substrates, detecting the activity of the light chain, rather than the toxin protein. The results provide guidance for further steps in quality assurance and highlight problems to address in the future.

Pharmacotherapy for the management of achalasia: Current status, challenges and future directions

This article reviews currently available pharmacological options available for the treatment of achalasia, with a special focus on the role of botulinum toxin (BT) injection due to its superior therapeutic effect and side effect profile. The discussion on BT includes the role of different BT serotypes, better pharmacological formulations, improved BT injection techniques, the use of sprouting inhibitors, designer recombinant BT formulations and alternative substances used in endoscopic injections. The large body of ongoing research into achalasia and BT may provide a stronger role for BT injection as a form of minimally invasive, cost effective and efficacious form of therapy for patients with achalasia. The article also explores current issues and future research avenues that may prove beneficial in improving the efficacy of pharmacological treatment approaches in patients with achalasia.

Aesthetic use of BoNT: Options and outcomes

There are a multitude of uses for BoNT in the aesthetic realm. Efficacy has been shown in softening glabellar creases, crows feet, forehead rhytides, and in correcting facial asymmetries, including mild eyelid ptosis. Facial shape can be altered through injections of BoNT into masseter, and smiles can be altered with BoNT. Clinical examples of the above will be shown, as well as adverse outcomes with inaccurate injection techniques.