Botulinum toxin: examining duration of effect in facial aesthetic applications

Subjective rating of cosmetic treatment with botulinum toxin type A: do existing measures demonstrate interobserver validity?

BACKGROUND

Throughout the literature, investigators have assessed the cosmetic efficacy of botulinum toxin (BT) treatment by using various subjective, qualitative measures, including the Facial Wrinkle Scale (FWS) and Subject Global Assessment (SGA). The widely used FWS and SGA attempt to quantify both the magnitude and duration of cosmetic outcomes as assessed by physician and patient. We sought to determine the interobserver validity of these scales relative to the level of observer experience.

METHODS

Botulinum toxin injections were performed to cosmetic effect in 6 patients recruited as part of an institutional review board-approved investigation. Subjects were photographed at rest and during animation (raising eyebrows, frowning, and blinking) before treatment and at 1, 2, 4 weeks, and monthly with follow-up to 6 months. Standardized digital 8″×10″ prints were scored using the FWS by board-certified plastic surgeons (n=5), general surgery residents (n=3), and medical students (n=4). Photographs at each time point were then compared to baseline using the SGA. Statistical analysis of observer data was performed using SPSS v19. Cohen κ (FWS) and Spearman ρ (SGA) were calculated for each pairwise comparison of observer data, with a conservative α of 0.01.

RESULTS

The FWS observer scores for the upper face overall were generally in agreement, with no negative κ values. The distribution, even among members of a single group, was highly variable. Agreement among plastic surgeons was the greatest (κ, 0.194-0.609). Resident concordance was moderate, and medical students displayed the most variable agreement. Spearman ρ for SGA scores was much higher, with surgeons approaching excellent agreement (κ, 0.443-0.992). In comparisons between members of different groups, agreement was unpredictable for both the FWS and SGA. Comparisons using scores from individual areas of the face were least concordant.

CONCLUSIONS

The FWS and SGA represent the current standard of cosmetic outcomes measures; however, when subjected to scrutiny they display relatively unpredictable agreement even among plastic surgeons. Compared to the FWS, the SGA has a more acceptable user concordance, especially among plastic surgeons accustomed to using such scales. The interobserver variability of FWS and SGA scoring underlines the need to explore objective, quantitative cosmetic outcomes measures.

OnabotulinumtoxinA: a meta-analysis of duration of effect in the treatment of glabellar lines

BACKGROUND

Duration of effect of aesthetic treatments with botulinum toxin potentially influences subject satisfaction, treatment frequency, and annual costs, but quantitative outcomes for measuring duration of effect and correlations with subject satisfaction have yet to be fully elucidated.

METHODS AND MATERIALS

Phase III clinical trials with similar designs were identified and their data pooled to ascertain duration of clinical effect of onabotulinumtoxinA in glabellar muscles. Duration was calculated using the Kaplan-Meier method for investigator-rated Facial Wrinkle scale (FWS) scores and subject global assessment (SGA) of glabellar lines. Responders were determined according to FWS score at maximum contraction and at repose 30 days after injection.

RESULTS

Data from four trials with 621 onabotulinumtoxinA-treated (20 U) subjects were analyzed, 523 of these (84.2%) were identified as day-30 responders on the FWS at maximum contraction. Pooled median duration of effect for day-30 responders was 120 days for FWS at maximum contraction and 131 days for FWS at repose. Higher day 30 SGA scores were correlated with a greater duration of effect on dynamic, but not static lines.

CONCLUSION

Treatment of glabellar lines with 20 U of onabotulinumtoxinA resulted in sustained clinical benefit for 4 months in more than 50% of responders; subject satisfaction increased with duration of effect.

Compositional differences among commercially available botulinum toxin type A

PURPOSE OF REVIEW

Since the advent of botulinum neurotoxin (BoNT) in the facial cosmetic field, it has become the leading nonsurgical cosmetic procedure in the USA, and several different formulations are currently in use. The aim of this study is to review the major 'players' in order to help the physician understand the clinically relevant dissimilarities between the products and by that promote treatment efficacy and patient satisfaction.

RECENT FINDINGS

The different available formulations can be classified into two groups by the existence of absence of complexing proteins. Most of the influence that was previously attributed to these proteins has been found to be less relevant clinically, the immune response being the only remaining issue with supporting evidence in the literature.

SUMMARY

Botulinum toxin type A is widely utilized in the cosmetic field, and it seems that all available and approved formulations are both well tolerated and effective in treating facial rhytids. The treating physician must be familiar with the differences between all the products, especially the fact that they are not interchangeable in respect to their recommended dosage.

Effectiveness of type A botulinum toxins for aesthetic indications and their relative economic impact

BACKGROUND

It is accepted that the three commercially available type A botulinum toxins (BoNT-As) are different, their units of potency are not interchangeable and no fixed dose conversion ratio exists between them. To date, there is no clear evidence demonstrating the superiority of one toxin over another clinically.

OBJECTIVE

The study aims to identify evidence confirming the equivocal efficacy of the formulations and to justify that attention can therefore be reasonably turned to their differing costs as a means of aiding choice of treatment. This is achieved via the development of the cost calculator presented herein, to enable direct economic comparisons to be made between the three commercially available BoNT-A formulations licensed for aesthetic indications in the UK.

METHODS

An online literature search using PubMed was undertaken and the latest available information on the cost for each BoNT-A treatment was accessed via the British National Formulary (BNF). Predicated on the evidence review, a cost calculator was developed which takes into account for the glabella: the number of treatments needed per patient with each product over a year and the number of treatments available with differing dilutions of each vial of each product over a year. A range of cost prices can also be introduced allowing a direct cost-comparison to be made for treating the glabella of a set number of patients over a year between different products.

RESULTS

Azzalure(®) (abobotulinumtoxinA) was the most cost-effective in almost all scenarios tested, whilst Vistabel(®) (onabotulinumtoxinA) was the least cost-effective. Of the two products with published non-inferiority with respect to each other, onabotulinumtoxinA and Bocouture(®) (incobotulinumtoxinA), incobotulinumtoxinA offered a lower overall cost to treat the glabella of the same number of patients when compared with Vistabel.

CONCLUSION

In most scenarios, BoNT-A treatment with abobotulinumtoxinA will result in significant annual cost savings when compared with treatment with onabotulinumtoxinA or incobotulinumtoxinA.

Prospective randomized comparison of onabotulinumtoxinA (Botox) and abobotulinumtoxinA (Dysport) in the treatment of forehead, glabellar, and periorbital wrinkles

BACKGROUND

There are several commercially available neurotoxins to improve facial aesthetics, but few prospective, randomized trials have been conducted without commercial support to compare these agents.

OBJECTIVES

The authors present the results of a study examining and comparing the effects of onabotulinumtoxinA (BoNT-ONA; Botox, Allergan, Inc., Irvine, California) and abobotulinumtoxinA (BoNT-ABO; Dysport, Ipsen Ltd, Slough, UK).

METHODS

The authors enrolled 53 patients in a prospective, randomized trial in which each patient received a dose of BoNT-ONA on one side of the upper face and BoNT-ABO on the other. The effects of each agent were monitored and recorded over 150 days according to each patient's ability to elevate the brow, wrinkle count (as measured by the Visia system; Canfield Imaging Systems, Fairfield, New Jersey), and assessment of Fitzpatrick wrinkle scale rankings by blinded graders.

RESULTS

Results showed no statistically significant differences between the two agents. Both agents yielded measurable improvements on wrinkles of the upper face at 150 days.

CONCLUSIONS

At the current pricing of the agents, BoNT-ABO offers a significant cost savings over BoNT-ONA, with a comparable efficacy. The effect of both drugs appears to be more prolonged than indicated in the current manufacturer guidelines.

Antibody-induced secondary treatment failure in a patient treated with botulinum toxin type A for glabellar frown lines

Botulinum toxin type A (BTX-A) preparations are widely used nonsurgical treatments for facial wrinkles. Higher doses of BTX-A are also used for therapeutic purposes in the treatment of conditions involving increased muscle tone, such as cervical dystonia. The phenomenon of antibody-induced treatment failure is well known in the therapeutic setting, but reports are also emerging following cosmetic use of BTX-A. We describe the case of a 41-year-old female nurse who developed secondary treatment failure during 6 years of BTX-A treatment for glabellar lines. After a good response to the first BTX-A injection, the intensity and duration of effect decreased after subsequent treatments. Antibody tests revealed a high titer of neutralizing anti-BTX-A antibodies. This case shows secondary treatment failure due to the production of neutralizing antibodies following administration of BTX-A formulations for cosmetic purposes and demonstrates that immunogenicity of BTX-A preparations is an important consideration, even in the cosmetic setting.

Botulinum toxin dosage template for frontal wrinkle effacement

BACKGROUND

There is no consensus in the literature about the ideal technique for precisely placing botulinum toxin in the frontal facial regions for the most natural posttreatment appearance.

OBJECTIVES

The authors describe a safe and effective dosage template for botulinum toxin injection (a "dose disc," which makes it possible to estimate the approximate area to which the action of the toxin dose will reach, thereby guiding the positioning of the injection in a very practical way) for frontal wrinkle effacement, preserving residual movement whenever possible.

METHODS

Fifty adult patients who presented to the authors' private clinic between January 2009 and May 2010 with aesthetic concerns about cutaneous expression wrinkles in the frontal region of their faces were selected for this study. Patients were sequentially divided into two groups: Group 1 included the first 15 patients, who underwent injections in the frontal region on the first visit and glabellar injections 15 days later; Group 2 included the subsequent 35 patients, who underwent frontal and glabellar treatment simultaneously. All pretreatment markings in both groups were made with the authors' "dose disc, which allows for overlap of the "halos" of effect.

RESULTS

In the 50 patients included in the study, 317 injections were performed with the dose disc. Two treatment failures occurred (etiology unknown), and five patients presented with failure due to irregular technical positioning of the discs. The latter patients were treated at the beginning of the study and exhibited residual wrinkles. Only one case of complete toxin inactivity was observed. All patients with treatment failures underwent successful correction with additional injections. There was no evidence of palpebral ptosis, eyebrow ptosis, or any other serious diffusion or positioning side effects.

CONCLUSIONS

A fixed dose disc template can be a useful tool for botulinum toxin injections in the frontal region of the face. Future studies assessing other disc models for different doses and different injection methods are needed, with the goal of establishing a longer duration of the effect and devising similar templates for other facial areas.

Treating glabellar lines with botulinum toxin type A-hemagglutinin complex: a review of the science, the clinical data, and patient satisfaction

Botulinum toxin type A treatment is the foundation of minimally invasive aesthetic facial procedures. Clinicians and their patients recognize the important role, both negative and positive, that facial expression, particularly the glabellar frown lines, plays in self-perception, emotional well-being, and perception by others. This article provides up-to-date information on fundamental properties and mechanisms of action of the major approved formulations of botulinum toxin type A, summarizes recent changes in naming conventions (nonproprietary names) mandated by the United States Food and Drug Administration, and describes the reasons for these changes. The request for these changes provides recognition that formulations of botulinum toxins (eg, onabotulinumtoxinA and abobotulinumtoxinA) are not interchangeable and that dosing recommendations cannot be based on any one single conversion ratio. The extensive safety, tolerability, and efficacy data are summarized in detail, including the patient-reported outcomes that contribute to overall patient satisfaction and probability treatment continuation. Based on this in-depth review, the authors conclude that botulinum toxin type A treatment remains a cornerstone of facial aesthetic treatments, and clinicians must realize that techniques and dosing from one formulation cannot be applied to others, that each patient should undergo a full aesthetic evaluation, and that products and procedures must be selected in the context of individual needs and goals.