Dose equivalence of two commercial preparations of botulinum neurotoxin type A: time for a reassessment?

Onabotulinumtoxin Type A Dosage for Upper Face Expression Lines in Males: A Systematic Review of Current Recommendations

BACKGROUND

Botulinum toxin injection is the most commonly performed minimally invasive aesthetic procedure in men. Despite various recommendations by experts on the use of onabotulinumtoxin type A in the literature, distinct guidelines for its use in males and females do not exist.

OBJECTIVES

The aim of this study was to delineate safe and effective doses for the use of onabotulinumtoxin type A in males for correction of upper facial expression lines.

METHODS

PubMed (MEDLINE), Embase, the Cochrane database, and Google Scholar were searched from 2002 to 2019 inclusive. Three researchers independently assessed trials for inclusion, extracted data, checked for accuracy, and assessed the evidence with AGREE II.

RESULTS

Average dosing recommended for the treatment of upper face expression lines was specific to glabellar frown lines, crow's feet, and horizontal forehead lines. Changing trends and gender variation was noted in each of the studies. Six of the 11 recommendations suggest the need to alter dosing in male patients, although do not give separate recommendations.

CONCLUSIONS

There is an urgent need for up-to-date recommendations for the use of onabotulinumtoxin type A in upper face expression lines of male patients.

A consensus statement on the use of botulinum toxin in pediatric patients

Botulinum toxin has been used in medicine for the past 30 years. However, there continues to be controversy about the appropriate uses and dosing, especially in the pediatric population. A panel of nine pediatric physiatrists from different regions and previous training programs in the United States were nominated based on institutional reputation and botulinum toxin (BoNT) experience. Based on a review of the current literature, the goal was to provide the rationale for recommendations on the administration of BoNT in the pediatric population. The goal was not only to review safety, dosing, and injection techniques but also to develop a consensus on the appropriate uses in the pediatric population. In addition to upper and lower limb spasticity, the consensus also provides recommendations for congenital muscular torticollis, cervical dystonia, sialorrhea, and brachial plexus palsies.

Cognitive Performance After Facial Botulinum Toxin Treatment in a Cohort of Neurologic Patients: An Exploratory Study

OBJECTIVE

To investigate higher cognitive functions after mimicry changes after facial botulinum toxin (BTX) injections, we tested verbal and nonverbal reasoning in patients with blepharospasm or hemifacial spasm before and after their long-term botulinum toxin treatment.

DESIGN

Explorative, nonrandomized, clinical trial.

SETTING

Patients receiving ambulatory care and control participants from the general community.

PARTICIPANTS

Volunteer sample (N=84) of patients (n=21) with blepharospasm or hemifacial spasm who received facial BTX injections. Control participants included patients (n=30) with cervical dystonia who received cervical BTX injections and individuals without neurological disorders (n=33).

INTERVENTIONS

The 2 groups receiving injections were tested before and 3 weeks after their treatment. The group without neurological disorders received no injections.

MAIN OUTCOME MEASURES

Verbal and nonverbal reasoning scores.

RESULTS

The key unexpected finding was that patients who received facial BTX injections perform significantly worse in nonverbal reasoning tasks, when compared with those who did not receive injections (P=.022). There was no significant difference in the baseline reasoning scores and at follow-up for verbal reasoning between the 3 groups. There was no correlation between toxin dose and reasoning scores (verbal: P=.132; nonverbal: P=.294).

CONCLUSIONS

Because of potential confounders, the results do not yet allow any conclusion on causality. Further research is needed to confirm our findings.

Low-Dose Pre-Operative Botulinum Toxin A Effectively Facilitates Complex Ventral Hernia Repair: A Case Report and Review of the Literature

Background: Complex ventral hernias following laparotomy present a unique challenge in that repair is hindered by the lateral tension of the abdominal wall. A novel approach to overcome this is the “chemical component separation” technique. Here, botulinum toxin A (BTA) is instilled into the muscles of the abdominal wall. This induces flaccid paralysis and effectively reduces tension in the wall, allowing the muscles to be successfully joined in the midline during surgery. We describe a method where a large incisional hernia was repaired using this technique and review the variations in methodology. Case report: A woman in her mid-40s developed a ventral hernia in the setting of a previous laparotomy for a small bowel perforation. Computed tomography (CT) of the abdomen demonstrated an 85 (Width) × 95 mm (Length) ventral hernia containing loops of the bowel. Pre-operative botulinum toxin A administration was arranged at the local interventional radiology department. A total of 100 units of BTA were instilled at four sites into the muscular layers of the abdominal wall under CT-fluoroscopic guidance. She underwent an open incisional hernia repair 4 weeks later, where the contents were reduced and the abdominal wall layers were successfully joined in the midline. There was no clinical evidence of hernia recurrence at 3-months follow-up. Conclusion: Low-dose BTA effectively facilitates the surgical management of large ventral incisional hernias. There is, however, significant variation in the dosage, concentration and anatomical landmarks in which BTA is administered as described in the literature. Further studies are needed to assess and optimise these variables.

The mechanisms of action and use of botulinum neurotoxin type A in aesthetics: Key Clinical Postulates II

BACKGROUND

The literature on botulinum neurotoxin type A (BoNT-A) is extensive, often contradictory, and confounded by a competitive market of products and research attempting to distinguish brand individuality.

METHODS

A comprehensive review of literature on the principles of BoNT-A in aesthetics as well as clinical examples.

RESULTS

In 2017, the Eight Key Clinical Postulates were formulated as a guide for the aesthetic practitioner in understanding BoNT-A pharmacodynamics and to compare different toxins. These are now updated to include (a) All type A toxins act identically; (b) The mathematical relationship between toxin and receptor is the basis of efficacy, and clinical efficacy is influenced by molecular potency and patient attributes including muscle mass, gender, age, and ethnicity; (c) Efficacy, onset, and duration are functions of "molecular potency" defined as the number of active 150 kDa molecules available for binding; (d) "Molecular potency" is difficult to objectively quantify for commercially available toxins; (e) Up to a point, increased molecular potency decreases time to onset and increases duration of effect, and the "Molecular Potency Quotient" is a construct for comparing molecular potency commercial cost; (f) The area of effect of a toxin injection is dependent upon molecular potency, diffusion (passive), and spread (active); (g) Differing reconstitution volumes; and (h) Increased number of injection sites can affect spread, onset, and duration of effect.

CONCLUSIONS

The principles of BoNT-A use in aesthetics are complex yet understandable as outlined in the framework of the updated Eight Key Clinical Postulates and serves as a useful tool for providing the most effective treatment and interpreting research on present and future toxin formulations.

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.

To switch from Botox to Dysport in children with CP, a real world, dose conversion, cost-effectiveness study

BACKGROUND AND OBJECTIVES

Children with cerebral palsy (CP) are routinely treated with botulinum toxin A (BoNT-A). Two non dose-equivalent and differently priced products, Botox and Dysport are used. Depending on the conversion one of the products is considerably cheaper. However, the dose conversion factors studied to date have varied widely and relevant studies have not included children. Our objective here was to compare the efficacy and health economics of the switch from Botox to Dysport in children with CP when conversion was set to 1:2. Specifically were these treatments perceived as equivalent in terms of efficacy, duration and side-effects and were the drug cost lowered by using Dysport.

METHODS

This prospective, real-world, cost-effectiveness population-based observational study included all children with CP, (n = 159) mean age 9.4 years (SD, 4.3), in the larger Stockholm area who received BoNT-A between September 1, 2014, and December 31, 2015. Parents reported the efficacy, duration and side-effects of previous treatment while physicians reported doses and goals set by children and parents for the present treatment. Drug acquisition costs were provided by county administrators.

RESULTS

In connection with 341 visits caregivers reported comparable effects of similar duration with these products, with few, similar and transient side-effects. The drug-cost per treatment was 4029 SEK for Botox and 2380 SEK in the case of Dysport.

CONCLUSION

When Botox was replaced by a two-fold higher Unit dose of Dysport (conversion 1:2) parents perceived the treatment of their children with CP to be equally effective while the cost was 41% lower according to procured prices.

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.

Comparison of different consensuses of BTXA in different countries

The most international dosing guidelines on the use of botulinum toxin type A (BTXA) drugs support a 1:1 dose relationship between OnaBTXA and IncoBTXA and 1:2.5 between OnaBTXA and AboBTXA. However, different facial zones demonstrate different doses conversion ratios. The comparative analysis of nine consensuses on the use of Abo-, Ona-, and IncoBTXA in the United States, Russia, and Europe has been performed. We conducted a review of publications adopting the key words "botulinum toxin consensus," "botulinum toxin guideline." Information search has been carried out primarily in specialized databases (DB). To find the relevant RCTs and guidelines/consensuses, the following databases were used: PubMed and Medline that were screened up to May 2008. Results regarding dose ratios for OnaBTXA:AboBTXA and IncoBTXA:AboBTXA showed that in most cases it is characterized both by increase and by decrease compared to the ratio of 1:2.5. The mean value of dose ratios OnaBTXA:AboBTXA adopted in the United States is 1:2.8. The ratio IncoBTXA:AboBTXA according to international and Russian data is 1:1.9. There are some differences in clinical approach of BTXA use in certain countries. In Russia, low doses are recommended for "crow's feet" and forehead. The US consensus recommends a higher dosage to correct perioral wrinkles. Despite many years of experience in using BTXA, there is no strict international uniformity of clinical guidelines. The recommended doses for the individual areas of the face may differ in different countries. Therefore, physicians in their practice should be guided not by international consensuses, but prefer a national guidelines.

In-vivo comparison of the neurotoxic potencies of incobotulinumtoxinA, onabotulinumtoxinA, and abobotulinumtoxinA

Three botulinum neurotoxin type A (BoNT/A) products, incobotulinumtoxinA, onabotulinumtoxinA, and abobotulinumtoxinA, all manufactured by different methods, are employed in clinical practice. Comparing the three BoNT/A products is difficult because their concentrations and volumes differ and the precise dose equivalence ratio is not known. We aimed to compare the neurotoxic potencies by a systematic analysis of injected volume and dose. The potency of BoNT in inducing hind limb paresis was assessed by analyzing the wheel-running performance of mice. To standardize the volume, the effect of an identical dose of incobotulinumtoxinA dissolved in different volumes of saline (15, 10, 5, and 2μl) was studied in four groups of mice (n=13-15). The potencies of the BoNT products were then compared by injecting identical volumes (10μl) containing different doses into both hind leg muscles. Mice injected with incobotulinumtoxinA showed a volume-dependent reduction in wheel-running, with larger volumes inducing more intense paresis. A standardized volume containing the same number of mouse units of the BoNT/A products produced different degrees of paresis. The conversion ratio of incobotulinumtoxinA and onabotulinumtoxinA is estimated to be between 1:0.75 and 1:0.5. OnabotulinumtoxinA displayed a two-fold greater potency than abobotulinumtoxinA. Doses of onabotulinumtoxinA and abobotulinumtoxinA that produce an identical severity of pareses even result in the same duration of pareses. This wheel-running assay allows one to compare the neurotoxic potency of different volumes and doses of the BoNT products in vivo. Our results argue against common clinical practice because incobotulinumtoxinA and onabotulinumtoxinA are not readily interchangeable and a two-fold dose of abobotulinumtoxinA is needed to induce an effect identical to onabotulinumtoxinA. In addition, this emphasizes that the duration of BoNT-induced effect is the same as long as equipotent doses of BoNT are injected.

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.

Botulinum Toxin Treatment for Limb Spasticity in Childhood Cerebral Palsy

CP is the most common cause of chronic disability in childhood occurring in 2–2.5/1000 births. It is a severe disorder and a significant number of patients present cognitive delay and difficulty in walking. The use of botulinum toxin (BTX) has become a popular treatment for CP especially for spastic and dystonic muscles while avoiding deformity and pain. Moreover, the combination of physiotherapy, casting, orthotics and injection of BTX may delay or decrease the need for surgical intervention while reserving single-event, multi-level surgery for fixed musculotendinous contractures and bony deformities in older children. This report highlights the utility of BTX in the treatment of cerebral palsy in children. We include techniques for administration, side effects, and possible resistance as well as specific use in the upper and lower limbs muscles.

Systematic Literature Review of AbobotulinumtoxinA in Clinical Trials for Blepharospasm and Hemifacial Spasm

Background

The aim was to elucidate clinical trial efficacy, safety, and dosing practices of abobotulinumtoxinA (ABO) treatment in adult patients with blepharospasm and hemifacial spasm. To date, most literature reviews for blepharospasm and hemifacial spasm have examined the effectiveness of all botulinum neurotoxin type A products as a class. However, differences in dosing units and recommended schemes provide a clear rationale for reviewing each product separately.

Methods

A systematic literature review was performed to identify randomized controlled trials and other comparative clinical studies of ABO in the treatment of blepharospasm and hemifacial spasm published in English between January 1991 and March 2015. Medical literature databases (PubMed, Cochrane library, EMBASE) were searched. A total of five primary publications that evaluated ABO for the management of blepharospasm and hemifacial spasm were identified and summarized.

Results

Data included 374 subjects with blepharospasm and 172 subjects with hemifacial spasm treated with ABO. Total ABO doses ranged between 80 and 340 U for blepharospasm and 25 and 85 U for hemifacial spasm, depending on the severity of the clinical condition. All studies showed statistically significant benefits for the treatment of blepharospasm and hemifacial spasm. ABO was generally well tolerated across the individual studies. Adverse events considered to be associated with ABO treatment included: ptosis, tearing, blurred vision, double vision, dry eyes, and facial weakness.

Discussion

These data from 5 randomized clinical studies represents the available evidence base of ABO in blepharospasm and hemifacial spasm. Future studies in this area will add to this evidence base.

Best clinical practice in botulinum toxin treatment for children with cerebral palsy

Botulinum toxin A (BoNT-A) is considered a safe and effective therapy for children with cerebral palsy (CP), especially in the hands of experienced injectors and for the majority of children. Recently, some risks have been noted for children with Gross Motor Classification Scale (GMFCS) of IV and the risks are substantial for level V. Recommendations for treatment with BoNT-A have been published since 1993, with continuous optimisation and development of new treatment concepts. This leads to modifications in the clinical decision making process, indications, injection techniques, assessments, and evaluations. This article summarises the state of the art of BoNT-A treatment in children with CP, based mainly on the literature and expert opinions by an international paediatric orthopaedic user group. BoNT-A is an important part of multimodal management, to support motor development and improve function when the targeted management of spasticity in specific muscle groups is clinically indicated. Individualised assessment and treatment are essential, and should be part of an integrated approach chosen to support the achievement of motor milestones. To this end, goals should be set for both the long term and for each injection cycle. The correct choice of target muscles is also important; not all spastic muscles need to be injected. A more focused approach needs to be established to improve function and motor development, and to prevent adverse compensations and contractures. Furthermore, the timeline of BoNT-A treatment extends from infancy to adulthood, and treatment should take into account the change in indications with age.

Practical guidance for CD management involving treatment of botulinum toxin: a consensus statement

Cervical dystonia is a neurological movement disorder causing abnormal posture of the head. It may be accompanied by involuntary movements which are sometimes tremulous. The condition has marked effects on patients’ self-image, and adversely affects quality of life, social relationships and employment. Botulinum neurotoxin (BoNT) is the treatment of choice for CD and its efficacy and safety have been extensively studied in clinical trials. However, current guidelines do not provide enough practical information for physicians who wish to use this valuable treatment in a real-life setting. In addition, patients and physicians may have different perceptions of what successful treatment outcomes should be. Consequently, an international group of expert neurologists, experienced in BoNT treatment, met to review the literature and pool their extensive clinical experience to give practical guidance about treatment of CD with BoNT. Eight topic headings were considered: the place of BoNT within CD treatment options; patient perspectives and desires for treatment; assessment and goal setting; starting treatment with BoNT-A; follow-up sessions; management of side effects; management of non-response; switching between different BoNT products. One rapporteur took responsibility for summarising the current literature for each topic, while the consensus statements were developed by the entire expert group. These statements are presented here along with a discussion of the background information.

Dysport and Botox at a ratio of 2.5:1 units in cervical dystonia: a double-blind, randomized study

We aimed to compare Dysport (abobotulinumtoxinA, Ipsen Biopharm, Slough, UK) and Botox (onabotulinumtoxinA, Allergan, Irvine, CA, USA) at a 2.5:1 ratio in the treatment of cervical dystonia (CD). A Dysport/Botox ratio of lower than 3:1 was suggested as a more appropriate conversion ratio, considering its higher efficacy and more frequent incidence of adverse effects not only in the treatment of CD but also in other focal movement disorders. A randomized, double-blind, multicenter, non-inferiority, two-period crossover study was done in CD, with a duration of at least 18 months. Patients were randomly assigned to treatment for the first period with Dysport or Botox, and they were followed up for 16 weeks after the injection. After a 4-week washout period, they were switched to the other formulation and then followed up for 16 weeks. The primary outcome was the changes in the Tsui scale between the baseline value and that at 1 month after each injection. A total of 103 patients were enrolled, and 94 completed the study. Mean changes in the Tsui scale between baseline and 4 weeks after each injection tended to favor Botox; however, this was not statistically significant (4.0 ± 3.9 points for the Dysport treatment vs. 4.8 ± 4.1 points for Botox; 95% confidence interval, −0.1-1.7; P = 0.091). The mean change of the Toronto western spasmodic torticollis rating scale score, the proportion of improvement in clinical global impression and patient global impression, and the incidences of adverse events were not significantly different between the two treatments. With regard to safety and efficacy, Dysport was not inferior to Botox in patients with CD at a conversion factor of 2.5:1. [http//clinicaltrial.gov: NCT00950664] © The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Isolation and quantification of botulinum neurotoxin from complex matrices using the BoTest matrix assays

Accurate detection and quantification of botulinum neurotoxin (BoNT) in complex matrices is required for pharmaceutical, environmental, and food sample testing. Rapid BoNT testing of foodstuffs is needed during outbreak forensics, patient diagnosis, and food safety testing while accurate potency testing is required for BoNT-based drug product manufacturing and patient safety. The widely used mouse bioassay for BoNT testing is highly sensitive but lacks the precision and throughput needed for rapid and routine BoNT testing. Furthermore, the bioassay's use of animals has resulted in calls by drug product regulatory authorities and animal-rights proponents in the US and abroad to replace the mouse bioassay for BoNT testing. Several in vitro replacement assays have been developed that work well with purified BoNT in simple buffers, but most have not been shown to be applicable to testing in highly complex matrices. Here, a protocol for the detection of BoNT in complex matrices using the BoTest Matrix assays is presented. The assay consists of three parts: The first part involves preparation of the samples for testing, the second part is an immunoprecipitation step using anti-BoNT antibody-coated paramagnetic beads to purify BoNT from the matrix, and the third part quantifies the isolated BoNT's proteolytic activity using a fluorogenic reporter. The protocol is written for high throughput testing in 96-well plates using both liquid and solid matrices and requires about 2 hr of manual preparation with total assay times of 4-26 hr depending on the sample type, toxin load, and desired sensitivity. Data are presented for BoNT/A testing with phosphate-buffered saline, a drug product, culture supernatant, 2% milk, and fresh tomatoes and includes discussion of critical parameters for assay success.

Abo-, inco-, ona-, and rima-botulinum toxins in clinical therapy: a primer

Botulinum neurotoxin (BoNT) is an acetylcholine release inhibitor and a neuromuscular-blocking agent used for the treatment of a variety of medical and cosmetic indications. Currently, in the United States, there are four BoNT formulations licensed for use: abobotulinumtoxinA, incobotulinumtoxinA, onabotulinumtoxinA, and rimabotulinumtoxinB. These revised name designations were established to reinforce the understanding that each BoNT product has an individual potency and is not interchangeable with any other BoNT product. The therapeutic use of BoNTs is expanding and new formulations are on the horizon. This article is a primer that describes distinctions among currently available, licensed BoNT formulations. Toxin pharmacology, product characteristics, storage, handling, preparation, and dosages will be reviewed. In addition, issues related to dose equivalency ratios, immunogenicity, potency, and toxin spread will be discussed. Therapeutic indications and safety are discussed briefly. Knowledge of the available and licensed BoNT formulations and the ability to make distinctions in toxin pharmacology, product characteristics, and indications are vital for product selection, preparation, drug information, avoidance of drug errors, quality assurance, and patient safety.

Evidence for therapeutic interventions for hemiplegic shoulder pain during the chronic stage of stroke: a review

OBJECTIVE

To determine the effectiveness of therapeutic interventions targeting hemiplegic shoulder pain (HSP) more than 6 months post stroke.

METHODS

A literature search of multiple databases (PubMed, CINAHL, Ovid, and EMBASE) was conducted to identify articles published in the English language from 1980 to April 2012. Studies were included if (1) all participants were adults who had sustained a stroke; (2) research design was a randomized controlled trial (RCT) that examined the effectiveness of any treatment for HSP; (3) all participants had experienced stroke at least 6 months previously; and (4) an assessment of pain had been conducted before and after treatment using a standardized method. The following data were extracted: patient characteristics (ie, age, gender, time since stroke), sample size, study design, measurement of pain pre and post treatment, and adverse events.

RESULTS

Ten RCTs (PEDro scores 4-9) met inclusion criteria and included a total sample size of 388 individuals with a mean age of 53.2 years (range, 43.6-73.2). Mean time post stroke was 18.4 months. Three studies addressed the use of botulinum toxin type A (BTx-A); 2 studies examined electrical stimulation; 3 studies focused on intraarticular glenohumeral corticosteroid injections; 1 studied subacromial corticosteroid injections; and 1 study looked at massage therapy.

CONCLUSIONS

Positive outcomes were noted with the use of corticosteroid injections and electrical stimulation and conflicting results were seen regarding the use of BTx-A. Overall, these targeted therapies provide benefit in the treatment of HSP in individuals who are more than 6 months post stroke.

Detection of botulinum neurotoxin serotype A, B, and F proteolytic activity in complex matrices with picomolar to femtomolar sensitivity

Rapid, high-throughput assays that detect and quantify botulinum neurotoxin (BoNT) activity in diverse matrices are required for environmental, clinical, pharmaceutical, and food testing. The current standard, the mouse bioassay, is sensitive but is low in throughput and precision. In this study, we present three biochemical assays for the detection and quantification of BoNT serotype A, B, and F proteolytic activities in complex matrices that offer picomolar to femtomolar sensitivity with small assay volumes and total assay times of less than 24 h. These assays consist of magnetic beads conjugated with BoNT serotype-specific antibodies that are used to purify BoNT from complex matrices before the quantification of bound BoNT proteolytic activity using the previously described BoTest reporter substrates. The matrices tested include human serum, whole milk, carrot juice, and baby food, as well as buffers containing common pharmaceutical excipients. The limits of detection were below 1 pM for BoNT/A and BoNT/F and below 10 pM for BoNT/B in most tested matrices using 200-μl samples and as low as 10 fM for BoNT/A with an increased sample volume. Together, these data describe rapid, robust, and high-throughput assays for BoNT detection that are compatible with a wide range of matrices.

Diffusion of botulinum toxins

BACKGROUND

It is generally agreed that diffusion of botulinum toxin occurs, but the extent of the spread and its clinical importance are disputed. Many factors have been suggested to play a role but which have the most clinical relevance is a subject of much discussion.

METHODS

This review discusses the variables affecting diffusion, including protein composition and molecular size as well as injection factors (e.g., volume, dose, injection method). It also discusses data on diffusion from comparative studies in animal models and human clinical trials that illustrate differences between the available botulinum toxin products (onabotulinumtoxinA, abobotulinumtoxinA, incobotulinumtoxinA, and rimabotulinumtoxinB).

RESULTS

Neither molecular weight nor the presence of complexing proteins appears to affect diffusion; however, injection volume, concentration, and dose all play roles and are modifiable. Both animal and human studies show that botulinum toxin products are not interchangeable, and that some products are associated with greater diffusion and higher rates of diffusion-related adverse events than others.

DISCUSSION

Each of the botulinum toxins is a unique pharmacologic entity. A working knowledge of the different serotypes is essential to avoid unwanted diffusion-related adverse events. In addition, clinicians should be aware that the factors influencing diffusion may range from properties intrinsic to the drug to accurate muscle selection as well as dilution, volume, and dose injected.

Field effect of two commercial preparations of botulinum toxin type A: a prospective, double-blind, randomized clinical trial

BACKGROUND

The dose equivalence of commonly used commercial preparations of botulinum toxin type A, Dysport (abotulinumtoxinA [ABO] 500 U, Ipsen Biopharm Limited, Wrexham, United Kingdom) and Botox (onabotulinumtoxinA [ONA] 100 U, Allergan, Irvine, CA), remains unclear.

OBJECTIVE

We sought to evaluate the field effect for ABO and ONA at dose equivalences of 2.5:1.0 U and 2.0:1.0 U, in both muscular and sweat gland activity.

METHODS

In all, 59 female patients with forehead wrinkles were enrolled. Patients were randomized for dose equivalence between ABO and ONA, group A (2.0:1.0 U, ABO:ONA) or group B (2.5:1.0 U, ABO:ONA) administered in the frontalis muscles. Clinical assessment, Minor test, and electromyography evaluations were performed at baseline, 28 days, and 112 days.

RESULTS

In group B, the field of anhidrotic effect of ABO showed a greater area and larger horizontal diameter than ONA at 28 and 112 days. At maximum frontalis muscle activity (day 112) patients receiving ABO demonstrated greater improvement based on the Wrinkle Severity Scale. No differences were found in frontalis muscle activity at rest between groups A and B based on results of Wrinkle Severity Scale, electromyography, and interindividual variability data at 28 and 112 days.

LIMITATIONS

Currently, there are no objective measurements other than electromyography to evaluate the field effect of botulinum toxin type A in muscles.

CONCLUSION

At a dose equivalence of 2.0:1.0 U (ABO:ONA), similar field effects were found for both muscle and sweat gland activity. At a higher dose equivalence of 2.5:1.0 U (ABO:ONA), injections of ABO showed greater area and larger horizontal diameter in field of anhidrotic effect at 28 and 112 days than ONA.

The efficacy of botulinum toxin type A in managing chronic musculoskeletal pain: a systematic review and meta analysis

BACKGROUND

Botulinum toxin type A (BoNTA) is a neurotoxin that acts by inhibiting the release of neurotransmitters acetylcholine at neuromuscular junctions, thus reducing muscular contractions. Recent evidence suggests that BoNTA can reduce nociceptive activities of sensory neurons in animal models by inhibiting release of certain neuropeptides. Despite the therapeutic benefit of BoNTA in alleviating painful muscle spasms, its efficacy in other musculoskeletal pain conditions is less clear.

OBJECTIVE

We aim to examine the efficacy of BoNTA in reducing chronic musculoskeletal pain.

METHODS

Studies for inclusion in our report were identified using MEDLINE, EMBASE, PUBMED, Cochrane Central Register of Controlled Trials, CINAHL, and reference lists of relevant articles. Studies were considered eligible for inclusion if they were randomized controlled trials (RCTs), evaluating the efficacy of BoNTA injections in pain reduction. All studies were assessed and data were abstracted independently by paired reviewers. The outcome measures were baseline and final pain scores as assessed by the patients. The internal validity of trials was assessed with the Jadad scale. Disagreements were resolved through discussions.

MAIN RESULTS

Twenty-one studies were included in the systematic review and 15 of them were included in the final meta-analysis. There was a total of 706 patients in the meta-analysis, represented from trials of plantar fasciitis (n = 1), tennis elbow (n = 2), shoulder pain (n = 1), whiplash (n = 3), and myofascial pain (n = 8). Overall, there was a small to moderate pain reduction among BoNTA patients when compared to control (SMD = -0.27, 95% CI: -0.44 to -0.11). When the results were analyzed in subgroups, only tennis elbow (SMD = -0.44, 95% CI: -0.86 to -0.01) and plantar fasciitis (SMD = -1.04, 95% CI: -1.68 to -0.40) demonstrated significant pain relief. Although not in the meta-analysis, one back pain study also demonstrated positive results for BoNTA. Lastly, BoNTA was effective when used at ≥ 25 units per anatomical site or after a period ≥ 5 weeks.

CONCLUSION

In our meta-analysis, BoNTA had a small to moderate analgesic effect in chronic musculoskeletal pain conditions. It was particularly effective in plantar fasciitis, tennis elbow, and back pain, but not in whiplash or shoulder pain patients. However, more evidence is required before definitive conclusions can be drawn. On the other hand, there is convincing evidence that BoNTA lacks strong analgesic effects in patients with myofascial pain syndrome. A general dose-dependent and temporal response with BoNTA injections was also observed.

Selection and preference for botulinum toxins in the management of photoaging and facial lines: patient and physician considerations

Various noninvasive to minimally invasive techniques can be used for the improvement of cutaneous changes seen with photoaging. These include dermabrasion, chemical peels, ablative and nonablative lasers, and filler agents such as hyaluronic acid. However, the most common nonsurgical cosmetic procedure performed in the treatment of rhytides is injection with botulinum toxin. Its extensive safety history and relative ease of use by the practitioner has led to high satisfaction in millions of patients. Nonetheless, proper training of the fundamentals in injection technique, the choice of the appropriate candidate, and knowledge of potential adverse events are imperative to ensure a satisfactory and safe outcome.

Hemifacial spasm and reinnervation synkinesias: long-term treatment with either Botox or Dysport

Botulinum toxin is considered the treatment of choice for hemifacial spasm (HFS) and reinnervation synkinesias (RS). We present 133 patients with HFS (n = 97) and RS (n = 36) who have been treated with either Botox (n = 78) or Dysport (n = 55) exclusively for 6 years (range 2-12 years). The Botox dose was 21 +/- 8 MU, the Dysport dose 46 +/- 22 MU. The therapeutic effect started after 7.1 +/- 2.3 days and lasted for 12.5 +/- 3.9 weeks. It was stable throughout the observation period in 85% of all patients. Adverse effects occurred in 5.4% of injection series. No patient terminated treatment because of unsatisfactory results. Secondary therapy failure did not occur. With an effective conversion ratio of Botox:Dysport = 1:2.56 there were no differences between both drugs with respect to therapeutic efficacy and adverse effects thus confirming the hypothesis that there may not be intrinsic differences between both products.

Botulinum toxin type A for the management of glabellar rhytids

There is an increasing demand for minimally-invasive cosmetic procedures to arrest the aging process. Botulinum toxin type A injections are the most commonly used nonsurgical cosmetic procedures in the United States. There has been research spanning over two decades dedicated to safety, efficacy, dosing, and complications of botulinum toxin type A. There are now two Food and Drug Administration (FDA) approved botulinum toxin type A options in the United States: Botox(®) and Dysport(™), with new advances being made in the field.