Clinical impact of antibody formation to botulinum toxin A in children

Intrasphincteric Botox injections in Hirschsprung's disease: indications and outcome in 64 procedures over a ten-year period

BACKGROUND

Intrasphincteric botulinum toxin (Botox) injection for symptomatic postoperative anal achalasia in Hirschsprung's disease (HSCR) has found wide application in the last twenty years. The aim of this study was to describe effectiveness and functional outcome of a series of patients treated over a 10-year period.

METHODS

All consecutive HSCR patients who received intrasphincteric Botox injections between January 2007 and December 2016 were included. Demographic data and clinical features were collected. A detailed questionnaire focusing on outcome in the medium and long-term was administered to all families.

RESULTS

In the study period 64 intrasphincteric Botox injections were performed in 31 patients. Completed questionnaires were returned by 27 out of 28 eligible patients (96%) reporting improvement or symptoms resolution in 16 (59%). The highest success rates were experienced by patients younger than 4, with long HSCR forms and with recurrent enterocolitis (75%, 100% and 100% of success rates, respectively). No major complications occurred. Minor complications were described by 7 patients (26%).

CONCLUSIONS

Intrasphincteric Botox injection proved to be feasible, safe and reasonably effective in children with HSCR and postoperative anal achalasia. Infants and toddlers with long HSCR forms and recurrent bouts of enterocolitis are those who would benefit most from this treatment.

Immunogenicity to Botulinum Toxin Type A: A Systematic Review With Meta-Analysis Across Therapeutic Indications

BACKGROUND

Botulinum toxin A (BTX-A) is commonly employed as a neuromodulator in several neurological diseases and aesthetic indications. Formation of neutralizing antibodies (NAbs) after BTX-A injections may be responsible for treatment failure.

OBJECTIVES

The authors sought to quantify the prevalence of NAbs following treatment with Abobotulinumtoxin A, Incobotulinumtoxin A, and Onabotulinumtoxin A for therapeutic indications.

METHODS

An electronic systematic search (2000-2020) of PubMed, Scopus, Web of Science, and Embase was conducted. Original studies reporting prevalence of NAbs were included. Data analysis was carried out through open meta-analysis softwares.

RESULTS

Forty-three studies involving 8833 patients were included in this meta-analysis. The incidence of NAbs was 1.8% (summary estimate = 0.018, 95% CI [0.012, 0.023]); a meta-regression analysis revealed that BTX-A duration was significantly associated with increased incidence of NAbs (P = 0.007). Patients with dystonia had the highest incidence (7.4%) of NAbs against BTX-A (summary estimate = 0.074, 95% CI = [0.045, 0.103], I2 = 93.%, P < 0.00) followed by patients with spasticity (6.7%) and urological indications (6.2%). Abobotulinumtoxin A was associated with the highest incidence of NAbs (7.4%) (summary estimate = 0.074, 95% CI = [0.053, 0.096], I2 = 97.24%, P < 0.00) by the Incobotulinumtoxin A and Onabotulinumtoxin A 0.3% (summary estimate <0.003%, 95% CI = [-0.001, 0.007], P < 0.003).

CONCLUSIONS

Although the overall incidence of NAbs following BTX-A injections is relatively low, patients with secondary nonresponse to BTX-A with no apparent causes should be investigated for NAbs. A consensus needs to be developed for the optimal management of such patients.

LEVEL OF EVIDENCE: 2

Immunogenicity of Botulinum Toxin Formulations: Potential Therapeutic Implications

Botulinum neurotoxins (BoNTs) are proteins produced by bacteria of the Clostridium family. Upon oral ingestion, BoNT causes the neuroparalytic syndrome botulism. There are seven serotypes of BoNT (serotypes A-G); BoNT-A and BoNT-B are the botulinum toxin serotypes utilized for therapeutic applications. Treatment with BoNT injections is used to manage chronic medical conditions across multiple indications. As with other biologic drugs, immunogenicity after long-term treatment with BoNT formulations may occur, and repeated use can elicit antibody formation leading to clinical nonresponsiveness. Thus, approaching BoNT treatment of chronic conditions with therapeutic formulations that minimize stimulating the host immune response while balancing patient responsiveness to therapy is ideal. Immunogenicity is a clinical limitation in many settings that use biologic drugs for treatment, and clinically relevant immunogenicity reduction has been achieved through engineering smaller protein constructs and reducing unnecessary formulation components. A similar approach has influenced the evolution of BoNT formulations. Three BoNT-A products and one BoNT-B product have been approved by the Food and Drug Administration (FDA) for therapeutic use: onabotulinumtoxinA, abobotulinumtoxinA, incobotulinumtoxinA, and rimabotulinumtoxinB; a fourth BoNT-A product, daxibotulinumtoxinA, is currently under regulatory review. Additionally, prabotulinumtoxinA is a BoNT-A product that has been approved for aesthetic indications but not therapeutic use. Here, we discuss the preclinical and clinical immunogenicity data that exist within the scientific literature and provide a perspective for considering immunogenicity as a key factor in choice of BoNT formulation.

The Use of Botulinum Toxin for Treatment of Spasticity

Spasticity is one component of the upper motor neuron (UMN) syndrome resulting from a multitude of neurologic conditions, such as stroke, brain injury, spinal cord injury, multiple sclerosis, and cerebral palsy. It is clinically recognized as a phenomenon of velocity-dependent increase in resistance, i.e., hypertonia. Recent advances in the pathophysiology of spasticity improve our understanding of mechanisms underlying this complex phenomenon and its relations to other components of UMN syndrome (weakness and disordered motor control), as well as the resultant clinical problems. This theoretical framework provides a foundation to set up treatment goals and to guide goal-oriented clinical assessment and treatment. Among a spectrum of treatment options, botulinum toxin (BoNT) therapy is the preferred treatment for focal spasticity. The evidence is very robust that BoNT therapy effectively reduces spasticity; however, it does not improve voluntary movement. In this chapter, we highlight a few issues on how to achieve the best clinical outcomes of BoNT therapy, such as dosing, dilution, guidance techniques, adjunctive therapies, early treatment, repeated injections, and central effects, as well as the ways to improve motor function in selected subgroups of patients with spasticity. We also discuss the reasons of poor responses to BoNT therapy and when not to use BoNT therapy.

Frequency and risk factors of antibody-induced secondary failure of botulinum neurotoxin therapy

Objective

To investigate the risk factors of neutralizing antibody (NAB)–induced complete secondary treatment failure (cSTF) during long-term botulinum neurotoxin (BoNT) treatment in various neurologic indications.

Methods

This monocenter retrospective cohort study analyzed the data of 471 patients started on BoNT therapy between 1995 and 2015. Blood samples of 173 patients were investigated for NABs using the mouse hemidiaphragm test (93 with suspected therapy failure, 80 prospective study participants). The frequency of NAB-cSTF was assessed for various indications: hemifacial spasm, blepharospasm, cervical dystonia, other dystonia, and spasticity. A priori defined potential risk factors for NAB-cSTF were evaluated, and a stepwise binary logistic regression analysis was performed to identify independent risk factors.

Results

Treatment duration was 9.8 ± 6.2 years (range, 0.5–30 years; adherence, 70.6%) and number of treatment cycles 31.2 ± 22.5 (3–112). Twenty-eight of 471 patients (5.9%) had NAB-cSTF at earliest after 3 and at latest after 103 treatment cycles. None of the 49 patients treated exclusively with incobotulinumtoxinA over 8.4 ± 4.2 (1–14) years developed NAB-cSTF. Independent risk factors for NAB-cSTF were high BoNT dose per treatment, switching between onabotulinumtoxinA and other BoNT formulations (except for switching to incobotulinumtoxinA), and treatment of neck muscles.

Conclusions

We present a follow-up study with the longest duration to date on the incidence of NAB-cSTF in patients treated with various BoNT formulations, including incobotulinumtoxinA. Whereas the overall risk of NAB-cSTF is low across indications and BoNT formulations, our findings underpin the recommendations to use the lowest possible dose particularly in cervical dystonia, and to avoid unnecessary switching between different formulations.

Treatment of sialorrhoea with repeated ultrasound-guided injections of botulinum toxin A into the parotid and submandibular glands

Botulinum toxin injections are useful in patients with refractory sialorrhoea although the optimum treatment protocol and its efficacy over a long period of follow up are controversial. The aim of our prospective study was to examine the efficacy and complications of a protocol of repeated ultrasound-guided botulinum toxin injections of fixed doses at a tertiary children's hospital. A total of 79 procedures were done in 34 patients who were followed up for two years. The overall complication rate was 3%. The outcome measures considered included the Drooling Frequency Severity Scale (DFSS), visual analogue scale (VAS), and carers' assessments of the reduction in drooling. Our study highlighted two types on non-responders (primary and secondary) of which 3/34 required definitive surgical management. In summary, this study shows that a protocol of repeated injections of fixed doses of botulinum toxin A, while not beneficial in all cases, is a potentially valuable option for the safe and effective treatment of sialorrhoea in children.

Non-vascular interventional radiology in the paediatric alimentary tract

Paediatric interventional radiology is an evolving speciality which is able to offer numerous minimally invasive treatments for gastrointestinal tract pathologies. Here we describe interventions performed by paediatric interventional radiologists on the alimentary tract from the mouth to the rectum. The interventions include sclerotherapy, stricture management by dilation, stenting and adjunctive therapies such as Mitomycin C administration and enteral access for feeding, motility assessment and administration of enemas.

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.

Clinical and Urodynamic Results of Repeated Intradetrusor Onabotulinum Toxin A Injections in Refractory Neurogenic Detrusor Overactivity: Up to 5 Injections in a Cohort of Children With Myelodysplasia

OBJECTIVE

To determine the efficacy and safety of repeated intradetrusor onabotulinum toxin A (onaBoNT-A) injections in children with neurogenic detrusor overactivity due to myelodysplasia.

MATERIALS AND METHODS

The study group consisted of 19 children (4 boys and 15 girls) with a mean age of 10.3 ± 3.1 years old, who had received at least 2 injections of 10 U/kg onaBoNT-A for the treatment of urinary incontinence resistant to anticholinergic treatment and clean intermittent catheterization in our clinic, between 2010 and 2015. Controlled urodynamic studies were performed at the baseline and 3 months after each injection.

RESULTS

Eight of the children received 3 injections, 5 children had 4 injections, and 2 children had 5 injections. From the baseline to the fifth injection, the detrusor compliance (1.3, 4.5, 10, 20.7, 18.8, and 16.6 mL/cm H₂O), the maximum bladder capacity (82.0, 157.0, 191.0, 272.0, 299.0, and 210.5 mL), and the maximum detrusor pressure (55.0, 33.0, 22.0, 12.5, 16.0, and 12.5 cm H₂O) were assessed. The findings significantly improved following the first, second, and third injections, when compared with the previous bladder dynamics (P <.05), but the differences with the fourth were not statistically significant (P >.05). The continence periods were similar under clean intermittent catheterization after all of the injections (P <.05), and no severe side effects were observed.

CONCLUSION

Repeated onaBoNT-A injections are a safe treatment modality and can be offered as an effective alternative choice, instead of more invasive surgery, in children with neurogenic detrusor overactivity due to myelodysplasia.

Efficacy of Repeated Botulinum Toxin Type A Injections for Spastic Equinus in Children with Cerebral Palsy-A Secondary Analysis of the Randomized Clinical Trial

Botulinum toxin A is considered an important tool to control spasticity in children with cerebral palsy. Several factors are known to affect the efficacy of botulinum toxin, such as dosage, appropriate muscle selection and application, age, and accompanying therapy. A multicenter, double-blind, randomized, prospective phase III clinical trial of botulinum toxin A for the treatment of dynamic equinus in 144 children with cerebral palsy was performed to compare the efficacies of letibotulinumtoxin A and onabotulinumtoxin A. Secondary analyses were performed to evaluate factors that affected the outcome, focusing on the number of times injections were repeated. Effectiveness was defined as a change of 2 or more in the physician’s rating scale. Multivariate regression analyses were performed with multiple variables. The first injection of botulinum toxin A significantly improved D subscale of Gross Motor Function Measure-88 scores at 3 months compared to repeated injections (p < 0.05). After 6 months, patients who had one injection or none before the study showed significantly better outcomes than those who had more than one injection in terms of observational gait scores.

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.

Injection frequency of botulinum toxin A for spastic equinus: a randomized clinical trial

AIM

We compared two botulinum toxin A (BoNT-A) injection frequency regimens, 12-monthly versus 4-monthly, for spastic equinus in a randomized clinical trial. The primary outcome measure was passive ankle dorsiflexion.

METHOD

Forty-two ambulant children with spastic equinus, secondary to cerebral palsy (23 males and 19 females; mean age 3y 6mo, SD 13mo; GMFCS levels I [n=20], II [n=19], III [n=3]) were randomized to receive either 12-monthly or 4-monthly BoNT-A injections to the calf, over a 26-month period. Twenty-one children had spastic hemiplegia, 21 children had spastic diplegia. A fixed 6U/kg dose of Botox was injected into the gastrocnemius muscle of both limbs in children with diplegia and the gastrocsoleus of the affected limb in children with hemiplegia, under mask anaesthesia.

RESULTS

Forty-two children entered the trial with 21 participants randomized to each group. There were three withdrawals and two children received serial casting midway through the trial. There was no significant difference in passive dorsiflexion between 12-monthly and 4-monthly regimens (p=0.41). There were also no significant between group differences on secondary outcome measures. There were no serious adverse events - the rate was 1.2 adverse events per child per year in the 12-monthly group and 2.2 adverse events per child per year in the 4-monthly group. Subgroup analysis revealed a significant difference in passive dorsiflexion between children with hemiplegia and diplegia (p=0.01).

INTERPRETATION

There was no significant difference between 12-monthly and 4-monthly injection regimens on passive dorsiflexion or secondary outcome measures. BoNT-A injections for spastic equinus may be recommended on a 12-monthly basis.

Ultrasound-Guided Botulinum Toxin Type A Salivary Gland Injection in Children for Refractory Sialorrhea: 10-Year Experience at a Large Tertiary Children's Hospital

BACKGROUND

Sialorrhea is problematic for neurologically impaired children, and botulinum toxin A salivary gland injection has been reported as effective in reducing sialorrhea. This article assesses the success and safety of ultrasound-guided weight-based botulinum toxin A injection for the management of sialorrhea in children.

METHODS

A total of 111 patients (63 males; 48 females; average age 7 years) with refractory sialorrhea were treated with ultrasound-guided botulinum toxin type A salivary gland injections (144 procedures) from July 1, 2004, to July 1, 2014, using a single weight-based protocol. Patient history, procedural records, and clinical follow-up documents were retrospectively reviewed. Clinical data were compared with reported effectiveness and complications using odds ratios.

RESULTS

A total of 144 procedures were performed in 111 patients with refractory sialorrhea. Cerebral palsy was the most common underlying etiology for sialorrhea (29%), whereas others included encephalopathy (5%), anoxic brain injury (4%), and a variety of chromosomal anomalies (5%). There was a 100% technical success rate. Overall treatment effectiveness was 68%. Repeat injections were not associated with increased clinical success. No procedure-related deaths or major complications were identified; the minor complication rate was less than 2%.

CONCLUSIONS

The protocol used for ultrasound-guided injection of botulinum toxin A proved to be safe and effective in children suffering from sialorrhea. Image guidance technique may lead to a reduction in rates of adverse events reported in other series. Subsequent procedures do not improve upon initial efficacy.

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

Botulinum neurotoxin injections are a valuable treatment modality for many therapeutic indications and have revolutionized the field of aesthetic medicine so that they are the leading cosmetic procedure performed worldwide. Studies show that onabotulinumtoxinA, abobotulinumtoxinA, and incobotulinumtoxinA are comparable in terms of clinical efficacy. Differences between the products relate to the botulinum neurotoxin complexes, specific biological potency, and their immunogenicity. Protein complex size and molecular weight have no effect on biological activity, stability, distribution, or side effect profile. Complexing proteins and inactive toxin (toxoid) content increase the risk of neutralizing antibody formation, which can cause secondary treatment failure, particularly in chronic disorders that require frequent injections and long-term treatment. These attributes could lead to differences in therapeutic outcomes, and, given the widespread aesthetic use of these three neurotoxin products, physicians should be aware of how they differ to ensure their safe and effective use.

Botulinum Neurotoxins: Qualitative and Quantitative Analysis Using the Mouse Phrenic Nerve Hemidiaphragm Assay (MPN)

The historical method for the detection of botulinum neurotoxin (BoNT) is represented by the mouse bioassay (MBA) measuring the animal survival rate. Since the endpoint of the MBA is the death of the mice due to paralysis of the respiratory muscle, an ex vivo animal replacement method, called mouse phrenic nerve (MPN) assay, employs the isolated N. phrenicus-hemidiaphragm tissue. Here, BoNT causes a dose-dependent characteristic decrease of the contraction amplitude of the indirectly stimulated muscle. Within the EQuATox BoNT proficiency 13 test samples were analysed using the MPN assay by serial dilution to a bath concentration resulting in a paralysis time within the range of calibration curves generated with BoNT/A, B and E standards, respectively. For serotype identification the diluted samples were pre-incubated with polyclonal anti-BoNT/A, B or E antitoxin or a combination of each. All 13 samples were qualitatively correctly identified thereby delivering superior results compared to single in vitro methods like LFA, ELISA and LC-MS/MS. Having characterized the BoNT serotype, the final bath concentrations were calculated using the calibration curves and then multiplied by the respective dilution factor to obtain the sample concentration. Depending on the source of the BoNT standards used, the quantitation of ten BoNT/A containing samples delivered a mean z-score of 7 and of three BoNT/B or BoNT/E containing samples z-scores <2, respectively.

The influence of physical therapy and anti-botulinum toxin antibody on the efficacy of botulinum toxin-A injections in children with spastic cerebral palsy

OBJECTIVE

To identify factors associated with the efficacy of botulinum toxin-A (BoNT-A) injections.

METHODS

Thirty-eight children with spastic cerebral palsy (CP) received BoNT-A injections into the gastrocnemius. The baseline anti-botulinum antibodies were checked. The Static dorsiflexion range of motion (ROM), Modified Tardieu Scale (MTS) and Physician Rating Scale (PRS) were assessed at pre-injection as well as 4- and 12-week post-injection.

RESULTS

No samples contained anti-botulinum antibodies. Greater baseline MTS dynamic range was associated with greater changes in MTS dynamic ranges at 4-week post-injection. More frequent physical therapy was associated with greater changes in static dorsiflexion ROM at 4-week post-injection and greater changes in PRS at 4- and 12-week post-injection.

CONCLUSION

The improvement in PRS at 12-week post-injection was associated with the frequency of physical therapy. Therefore, intensive physical therapy programs may be necessary to maintain the beneficial effects of BoNT-A injections in children with CP.

Long-term follow-up after botulinum toxin A (BTX-A) injection into the detrusor for treatment of neurogenic detrusor hyperactivity in children

Purpose

To prove the long-term efficacy of BTX-A injection in the management of children with neurogenic detrusor hyperactivity.

Materials and methods

28 out of 145 children with neurogenic bladder (15 male and 13 female, mean age 10.7 years) who were treated between 2002 and 2010 and became non-responders to conservative treatment were included into the retrospective study.

We injected 10-12 U/kg of BTX-A (Botox^®) into the detrusor at 20-30 sites, sparing the trigone. The mean follow-up was 48 months (range 6-84 months).

Results

Group 1. 14 patients had a single injection of BTX-A. Five of them were successful.

Mean bladder reflex volume increased (from 62.9 to 117.5 ml), maximum detrusor pressure decreased (from 59 to 37.5 cm H₂O), detrusor compliance increased (from 4.8 to 9.5 ml/cm H₂O), and leak-point-pressure decreased (from 46.5 to 24.2 cm H₂O). Four patients did not respond and were treated by ileocystoplasty. Another five were lost to follow-up. Group 2. 14 patients had repeated (mean 2.5) injections of BTX-A with a mean interval of 13.7 months. In thirteen patients, urodynamic parameters of the first and last injection were similar to those obtained in Group 1, showing a good response. One patient received an ileocystoplasty.

Conclusion

BTX-A is a safe alternative in the treatment of detrusor hyperactivity in children with myelomeningocele (MMC). The efficacy lasted a mean of 12 months and urodynamic response was unchanged even after several injections. In our series, 21.7% of children with severe low-compliance bladders were non-responders.

Clinical relevance of botulinum toxin immunogenicity

Botulinum toxin type A is a 150 kD protein produced by Clostridium botulinum, which exists in a complex with up to six additional proteins. The ability of botulinum toxin to inhibit acetylcholine release at the neuromuscular junction has been exploited for use in medical conditions characterized by muscle hyperactivity. As such, botulinum toxin is widely recommended by international treatment guidelines for movement disorders and it has a plethora of other clinical and cosmetic indications. The chronic nature of these conditions requires repeated injections of botulinum toxin, usually every few months. Multiple injections can lead to secondary treatment failure in some patients that may be associated with the production of neutralizing antibodies directed specifically against the neurotoxin. However, the presence of such antibodies does not always render patients non-responsive. The reported prevalence of immunoresistance varies greatly, depending on factors such as study design and treated indication. This review presents what is currently known about the immunogenicity of botulinum toxin and how this impacts upon patient non-response to treatment. The complexing proteins may act as adjuvants and stimulate the immune response. Their role and that of neutralizing and non-neutralizing antibodies in the response to botulinum toxin is discussed, together with an assessment of current neutralizing antibody measurement techniques. Botulinum toxin preparations with different compositions and excipients have been developed. The major commercially available preparations of botulinum toxin are Botox® (onabotulinumtoxinA; Allergan, Inc., Ireland), Dysport® (abobotulinumtoxinA; Ipsen Ltd, UK), and Xeomin® (incobotulinumtoxinA; botulinum toxin type A [150 kD], free from complexing proteins; NT 201; Merz Pharmaceuticals GmbH, Germany). The new preparations of botulinum toxin aim to minimize the risk of immunoresistance in patients being treated for chronic clinical conditions.

Botulinum toxin type A treatment in children with cerebral palsy: evaluation of treatment success or failure by means of goal attainment scaling

BACKGROUND

There is considerable variability in the amount of response to BTX-A treatment between and within patients with cerebral palsy (CP).

AIMS

The purpose of this retrospective cohort study was to evaluate the clinical responsiveness of Botulinum toxin type A (BTX-A) treatment in children with CP and specifically delineate features of treatment success and failure.

METHODS

Four hundred and thirty-eight children (251 boys, 187 girls; mean age 8 years 2 months, SD 4 years) were included into the study. Goal Attainment Scaling (GAS) was used to classify and evaluate treatment efficacy. Two study groups were defined: one group with an excellent response (GAS≥60.0) and one group with a lack of response (GAS≤40.0) to BTX-A.

RESULTS

Seventy-five patients (17.1%) had an excellent response and treatment was found to be unsuccessful for 31 patients (7.1%). Children with a lack of response to BTX-A were significantly older compared to children with a high responsiveness (p=0.0013). In the latter group, more children received multi-level injections and fewer children had injections in proximal parts of the lower limb compared to the low responsiveness group (p=0.0024). Moreover, there was a significant difference in the use of different types of casts between both study groups (p=0.0263).

CONCLUSION

Age, level of treatment and casting seem to be crucial features of BTX-A treatment success or failure in children with CP.

Therapeutic use of botulinum toxin in neurorehabilitation

The botulinum toxins (BTX), type A and type B by blocking vesicle acetylcholine release at neuro-muscular and neuro-secretory junctions can result efficacious therapeutic agents for the treatment of numerous disorders in patients requiring neuro-rehabilitative intervention. Its use for the reduction of focal spasticity following stroke, brain injury, and cerebral palsy is provided. Although the reduction of spasticity is widely demonstrated with BTX type A injection, its impact on the improvement of dexterity and functional outcome remains controversial. The use of BTX for the rehabilitation of children with obstetrical brachial plexus palsy and in treating sialorrhea which can complicate the course of some severe neurological diseases such as amyotrophic lateral sclerosis and Parkinson's disease is also addressed. Adverse events and neutralizing antibodies formation after repeated BTX injections can occur. Since impaired neurological persons can have complex disabling feature, BTX treatment should be viewed as adjunct measure to other rehabilitative strategies that are based on the individual's residual ability and competence and targeted to achieve the best functional recovery. BTX therapy has high cost and transient effect, but its benefits outweigh these disadvantages. Future studies must clarify if this agent alone or adjunctive to other rehabilitative procedures works best on functional outcome.

Botulinum toxin assessment, intervention and after-care for lower limb spasticity in children with cerebral palsy: international consensus statement

Botulinum neurotoxin type-A (BoNT-A) has been used in association with other interventions in the management of spasticity in children with cerebral palsy (CP) for almost two decades. This consensus statement is based on an extensive review of the literature by an invited international committee. The use of BoNT-A in the lower limbs of children with spasticity caused by CP is reported using the American Academy of Neurology Classification of Evidence for therapeutic intervention. Randomized clinical trials have been grouped into five areas of management, and the outcomes are presented as treatment recommendations. The assessment of children with CP and evaluation of outcomes following injection of BoNT-A are complex, and therefore, a range of measures and the involvement of a multidisciplinary team is recommended. The committee concludes that injection of BoNT-A in children with CP is generally safe although systemic adverse events may occur, especially in children with more physical limitations (GMFCS V). The recommended dose levels are intermediate between previous consensus statements. The committee further concludes that injection of BoNT-A is effective in the management of lower limb spasticity in children with CP, and when combined with physiotherapy and the use of orthoses, these interventions may improve gait and goal attainment.

Botulinum toxin assessment, intervention and follow-up for paediatric upper limb hypertonicity: international consensus statement

The primary objective of this paper was to evaluate the published evidence of efficacy and safety of botulinum neurotoxin (BoNT) injections in paediatric upper limb hypertonia (PULH). Secondary objectives included the provision of clinical context, based on evidence and expert opinion, in the areas of assessment, child and muscle selection, dosing, and adjunctive treatment. A multidisciplinary panel of authors systematically reviewed, abstracted, and classified relevant literature. Recommendations were based on the American Academy of Neurology (AAN) evidence classification. Following a literature search, 186 potential articles were screened for inclusion, and 15 of these met the criteria and were reviewed. Grade A evidence was found to support the use of BoNT to reach individualized therapeutic goals for PULH. There is grade B evidence (probably effective) for tone reduction following BoNT injections and grade U evidence (inconclusive) for improvement in upper limb (UL) activity and function. BoNT injections were generally found to be safe and well tolerated with the most common side effect identified as a transient decrease in grip strength.

Clinical assessment and management of spasticity: a review

Spasticity is a sign of upper motor neurone lesion, which can be located in the cerebrum or the spinal cord, and be caused by stroke, multiple sclerosis, spinal cord injury, brain injury, cerebral paresis, or other neurological conditions. Management is dependent on clinical assessment. Positive and negative effects of spasticity should be considered. Ashworth score and the modified Ashworth score are the most used scales for assessment of spasticity. These and other spasticity scales are based on assessment of resistance during passive movement. The main goal of management is functional improvement. A novel 100-point score to assess disability, function related to spasticity (Rekand disability and spasticity score) is proposed. Management of spasticity should be multimodal and should always include physiotherapy or exercise. Oral medications such as baclofen and tizanidine have limited efficacy and considerable side effects, but are easiest to use. Botulinum toxin combined with physiotherapy and/or orthopaedic surgery is effective treatment of localized spasticity. Treatment with intrathecal baclofen via programmable implanted pump is effective in generalized spasticity, particularly in the lower extremities. Neurosurgical and orthopaedic procedures may be considered in intractable cases.

Botulinum toxin a injections to the upper limbs in children with cerebral palsy: duration of effect

We report our experience on the duration of effectiveness of botulinum toxin A injections to the upper extremities of children with cerebral palsy. A retrospective chart review was conducted on 30 consecutive patients (mean age, 9.9 ± 5.0 years) with spastic hemiparesis and quadriparesis. They received 1 to 5 treatments, totaling 56 treatments for the entire cohort. The injected muscles were the pronator teres (50/56), flexor carpi radialis (39/56), biceps (38/56), flexor carpi ulnaris (35/56), opponens (21/56), and adductor pollicis (17/56). Children were assessed for muscle tone and classified according to the Manual Ability Classification System before and after treatment. Functional improvement was apparent after 42 of 56 treatments, and muscle tone decreased significantly (P < .001). The mean duration of the effect was 7.0 ± 3.0 months. We conclude that the effect of botulinum toxin A to the upper limbs is retained for longer periods of time than those reported for lower limbs.

Experience with botulinum toxin type A in medically intractable pediatric chronic daily headache

In adults, botulinum toxin type A has been studied as a potentially effective treatment for chronic daily headache. For pediatric chronic daily headache, the literature evaluating efficacy of botulinum toxin type A is sparse, with no studies assessing tolerability. The purpose of this retrospective case series study was to assess tolerability and efficacy of botulinum toxin type A in the treatment of pediatric chronic daily headache. The series comprises 10 patients (ages 11-17 years) who received a standard 100-unit dose of onabotulinumtoxinA (trade name, Botox) for refractory chronic daily headache. Attention was given to therapeutic history, efficacy, and tolerability. The patients had attempted an average of 8.0 ± 2.40 S.D. therapies prior to botulinum toxin type A. Most patients reported adverse events from at least one of these prior medications. With botulinum toxin type A, four patients (40%) reported subjective but clinically meaningful relief, consisting of a decrease in headache intensity, and two patients additionally noted a decrease in headache frequency. The four responders noted improvements in quality of life. Three patients experienced minor adverse events from botulinum toxin type A. This case series suggests that botulinum toxin type A can be well tolerated and may be a useful therapeutic in pediatric patients with highly medically intractable chronic daily headache.

Botulinum toxin injections for pediatric patients with hereditary spastic paraparesis

Limited information is available on the use of botulinum toxin type A injections for children with hereditary spastic paraplegia. This report includes 12 children with hereditary spastic paraplegia (mean age 4.8 +/- 2.5 years) who underwent 1 to 6 sessions of botulinum toxin A injections to the hamstrings, adductors and gastrocnemius muscles. Patients showed both improved muscle tone (mean 1.9 +/- 0.5 vs 1.18 +/- 0.33, P < .001, Ashworth Scale) and motor function (75.3 +/- 11.9 vs 77.7 +/- 11, P < .001, Gross Motor Function Measure). The effect lasted for a mean of 6.6 +/- 3.6 months. During the study period (mean 2.8 +/- 1.8 years), the preinjection Gross Motor Function Measure increased (69.2 +/- 14.7 vs 78.3 +/- 13.5, P = .005), whereas the Ashworth Scale remained stable, suggesting a prolonged effect of botulinum toxin A on motor function. The authors conclude that botulinum toxin A injections to lower limbs of pediatric patients with hereditary spastic paraplegia result in prolonged functional improvement despite the progressive nature of the disease.

The use of botulinum toxin A in children with cerebral palsy, with a focus on the lower limb

PURPOSE

The purpose of this review is to clarify the role of botulinum toxin serotype A (BTX-A) in the treatment of children with cerebral palsy (CP), with a special focus on the lower limb.

BACKGROUND

The treatment of spasticity is central in the clinical management of children with CP. BTX-A blocks the release of acetylcholine at the motor end plate, causing a temporary muscular denervation and, in an indirect way, a reduced spasticity. Children with increased tone develop secondary problems over time, such as muscle contractures and bony deformities, which impair their function and which need orthopaedic surgery. However in these younger children, delaying surgery is crucial because the results of early surgical interventions are less predictable and have a higher risk of failure and relapse. As BTX-A treatment reduces tone in a selective way, it allows a better motor control and muscle balance across joints, resulting in an improved range of motion and potential to strengthen antagonist muscles, when started at a young age. The effects are even more obvious when the correct BTX-A application is combined with other conservative therapies, such as physiotherapy, orthotic management and casts. There is now clear evidence that the consequences of persistent increased muscle tone can be limited by applying an integrated multi-level BTX-A treatment approach. Nevertheless, important challenges such as patient selection, defining appropriate individual goals, timing, dosing and dilution, accuracy of injection technique and how to measure outcomes will be questioned. Therefore, "reflection is more important than injection" remains an actual statement.

The updated European Consensus 2009 on the use of Botulinum toxin for children with cerebral palsy

An interdisciplinary European group of clinical experts in the field of movement disorders and experienced Botulinum toxin users has updated the consensus for the use of Botulinum toxin in the treatment of children with cerebral palsy (CP). A problem-orientated approach was used focussing on both published and practice-based evidence. In part I of the consensus the authors have tabulated the supporting evidence to produce a concise but comprehensive information base, pooling data and experience from 36 institutions in 9 European countries which involves more than 10,000 patients and over 45,000 treatment sessions during a period of more than 280 treatment years. In part II of the consensus the Gross Motor Function Measure (GMFM) and Gross Motor Function Classification System (GMFCS) based Motor Development Curves have been expanded to provide a graphical framework on how to treat the motor disorders in children with CP. This graph is named "CP(Graph) Treatment Modalities - Gross Motor Function" and is intended to facilitate communication between parents, therapists and medical doctors concerning (1) achievable motor function, (2) realistic goal-setting and (3) treatment perspectives for children with CP. The updated European consensus 2009 summarises the current understanding regarding an integrated, multidisciplinary treatment approach using Botulinum toxin for the treatment of children with CP.

Long-term use of botulinum toxin type A in children with cerebral palsy: treatment consistency

At the University Hospital of Pellenberg (Belgium), more than 1000 patients have been treated with Botulinum toxin type A (BTX-A) over the last decade. Ten percent of these patients (n=106) received multiple (at least four times), multi-level, high-dosage treatments. The aim of this study was to evaluate the stability of dosage and treatment intervals in long-term, multi-level, high-dosage treated children with cerebral palsy and to evaluate the evidence for a safe and stable response to this treatment. Data on disease, age, dosage and target muscles were extracted for each treatment session of 106 patients who received multiple BTX-A treatment sessions. Patients had a follow-up of 4y 6mo (range 1y 8mo-8y 9mo) on average and received 4 to 12 BTX-A treatments within the period of January 1996 and December 2005. Patients received a mean dosage of 23.5+/-5.2U/kgbw at first treatment with stable subsequent values. Mean dosages for children with diplegia, hemiplegia and quadriplegia were 24.5+/-4.7U/kgbw, 15.9+/-3.7U/kgbw and 22.0+/-4.8U/kgbw, respectively. Mean age at first treatment was 4y 6mo (range 1y 11mo-18y 10mo) with a majority of patients (76.4%) first treated within 2 and 4y of age. Treatment intervals of approximately 1y remained stable within four, five and six subsequent treatments. Long-term, high-dosage, multi-level BTX-A applications can be considered as a safe and stable treatment option for children with cerebral palsy and the formation of antibodies, responsible for secondary non-response, can be indirectly precluded.

Upper limb function after botulinum toxin A treatment in cerebral palsy: Two years follow-up of six cases

The objective of this study was to investigate the effects of botulinum toxin A (BTXA) treatment on impairment and function of the upper limb during a 2-year follow-up period. A prospective longitudinal study design with assessments before and after intervention was utilized, involving six patients with cerebral palsy (three boys and three girls) aged 3 years 4 months to 11 years 11 months at commencement of study. The outcome measures were spasticity (modified Ashworth, MAS), active and passive range of movement (ROM), grips (pinch, key grip, 3-finger grip, narrow cylinder grip, wide cylinder grip, pen grip and diagonal grip; grasping, releasing; pronation-supination), bimanual functions, fine motor functions (Melbourne Assessment of Unilateral Upper Limb Function), movement pattern (Upper Limb Physician's Rating Scale, ULPRS), functional skills and self-care capability (Paediatric Evaluation of Disability Inventory, PEDI), upper extremity use (House Classification) and cosmetic appearance. The assessments were repeated by the same examiners at baseline and at 1, 3 and 6 months after each BTXA treatment and then every 6 months until 24 months. One subject received a total of four injections (at 0, 6, 12 and 18 months), one two injections (at 0 and 12 months) and four one injection at the beginning of the study period. Upper extremity surgery was performed on two subjects during the study and one was operated on 2 months after completion of the study. All children benefited from the BTXA treatment in terms of reduction in muscle tone and increase in active and passive ROM. By 6 months, spasticity returned, but in four children passive and especially active ROM remained better than at baseline. No significant changes in grips, bimanual tasks or Melbourne Assessment scores were detected. The change in movement pattern (ULPRS) was maintained for 3 months in two children and beyond this in four, thus extending beyond the pharmacologic effects of botulinum toxin A. All but one child showed improvement in PEDI functional skill and caregiver assistance scale scores during the 2-year period. The House classification showed a one-grade improvement in one child at 1 month and in one child at 3 months and a three-grade improvement in one child at 3 months after BTXA treatment. After each treatment, the parents reported at least a one-grade improvement in cosmetic appearance in all children at 1 month and in four children maintained at least until 6 months. In two subjects operated during the study period, a distinct improvement in active and passive ROM and a two-grade improvement in the House classification were observed after the operation. In this limited series, the reduction in muscle tone after BTXA treatment did not translate into better gripping or quality of fine motor functions (Melbourne Assessment) of the affected hand, but seemed to have a positive effect on upper limb movement pattern (ULPRS), upper extremity use (House Classification) and cosmetic appearance. Assessment of upper limb function in a child with cerebral palsy demands a variety of measures.

Prevalence of neutralising antibodies in patients treated with botulinum toxin type A for spasticity

Botulinum toxin (BT) has been used with great success to treat various muscle hyperactivity disorders. Occasionally, antibodies against BT (BT-AB) can be formed. When they are directed against the neurotoxin component of the BT drug, they are called neutralising antibodies. They can reduce the therapeutic effect partially or completely. We have measured neutralising BT-AB by use of the mouse diaphragm assay (MDA) in 42 adult patients with spasticity in the order of their appearance in the clinic. The patients had been treated for at least 2 years with BT type A (BT-A) and received on an average 14.2 +/- 6.1 BT-A injection series. BT-A was applied as Botox only, Dysport only or by sequential application of both preparations. The mean cumulative doses were 4,610 +/- 1,936 units Botox and 14,033 +/- 7,566 units Dysport, respectively. The mean treatment time was 4.5 +/- 1.8 (2-8) years. All patients were initially responsive to BT-A therapy. MDA detected BT-AB in 12% (5/42) of patients. However, in three patients the BT-AB titre was very low (<0.3 mIU/ml), in one it was intermediate (0.6 mIU/ml) and in one patient it was high (>1.0 mIU/ml). All BT-AB negative patients and also two of the patients with low BT-AB titre remained clinically responsive to BT therapy throughout the study. In conclusion, prevalence of BT-AB formation with clinical relevance (6%, 3/42) in adult patients with spasticity is not higher than that of BT-treated patients with cervical dystonia and much lower than that of BT-treated patients with infantile cerebral palsy.

Long-term effect of repeated injections of botulinum toxin in children with cerebral palsy: a prospective study

PURPOSE

To prospectively evaluate long-term effects of repeated botulinum toxin A (BTX-A) injections in children with cerebral palsy (CP).

METHODS

Repeated injections of BTX-A were offered to children with CP, according to clinical indications, for a maximum of four injections within a period of two years. Injections were administered into lower extremity muscles of 26 consecutive children (age 3.7 +/- 1.2 years, 16 boys) with hemiplegic or diplegic CP. Clinical assessments before and one month following each injection included a gross motor function measure (GMFM), a modified Ashworth scale, and range-of-motion of knee extension and ankle dorsiflexion.

RESULTS

Twelve children received two injections, six received three injections, five received one injection, and three received four injections. The most common reason for discontinuing treatment was the need for orthopedic surgery (n = 17). A long-term effect was demonstrated by a significant increase of the GMFM score before the first injection compared with the last injection for each patient (P < 0.0001). There was no comparable change in the muscle tone or range-of-motion. The mean rate of GMFM change during the study was significantly higher than literature norms for CP children (13.2 vs. 5.37 per year, respectively, P < 0.01). The increase of the GMFM score before and one-month after injection (short-term effect) was significantly higher after the first injection than after the last injection (P < 0.05). Similar results were found for the Ashworth scale and popliteal angle.

CONCLUSIONS

Botulinum toxin A injections have a long-term effect on gross motor function in children with CP even though the effect on muscle tone is short-term. The effect apparently declines with repeated injections, with most children benefitting from 2 to 3 injections.

Future aspects of botulinum neurotoxins

The future of botulinum neurotoxin (BoNT) development is expected to proceed along two lines: the development of novel indications and the development of novel products. New indications will likely be based on the neuromuscular mode of action of BoNTs, as well as action on primary sensory fibers and other neuronal types. Novel BoNT products may be designed for increased specificity or enhanced duration. As new products enter the market, it will be important for each to demonstrate efficacy and safety. Unfortunately, the future of BoNTs will also likely include attempts to obtain and distribute unlicensed and illegal BoNT products that may pose substantial risks to patients.

Repeated botulinum-A toxin injections in the treatment of myelodysplastic children and patients with spinal cord injuries with neurogenic bladder dysfunction

OBJECTIVES

To examine the effects of repeated detrusor injections of botulinum-A toxin (BTX) for possible changes in bladder function, muscular structure of the detrusor, increase in BTX tolerance (tachyphylaxis) and side-effects, as BTX is a new treatment alternative for patients with a neurogenic bladder condition that is difficult to treat and refractory to anticholinergic medication.

PATIENTS AND METHODS

Between 2000 and 2005, 19 patients with myelodysplasia (MDP) and 25 spinal cord-injured (SCI) patients were treated with repeated suburothelial BTX injections (Dysport, Ipsen-Pharma, Ettlingen, Germany) or injections into the intramural detrusor. The follow-up was > or = 3 years (range 3-5, median 4.5).

RESULTS

Detrusor compliance, bladder capacity, and detrusor pressure at maximum filling improved significantly (P < 0.001) compared to baseline after each BTX injection. There was prolonged efficacy of each BTX administration and all repeated injections in the paediatric and adult patients with neurogenic bladder dysfunction over a median follow-up of 4.5 years. There was no evidence for drug tolerance or changes in the morphological appearance of the bladder. Safety was good: no complications were associated with the injection procedure itself. Early in the treatment programme, three patients who received a dose of 1000 units Dysport showed systemic side-effects and generalized muscle weakness. These resolved without intervention and did not recur after reducing the adult dose to 750 units (paediatric dose 20 units/kg, not >400 units), which seems to be the optimum for good efficacy with an adequate safety margin.

CONCLUSION

BTX injection is a safe and effective treatment for neurogenic detrusor hyperreflexia. Repeat treatments are as effective as the first: there was no indication of a lack of efficacy due to tachyphylaxis, antibody formation, or fibrosis of the detrusor muscle in this sample.

Formation of neutralizing antibodies in patients receiving botulinum toxin type A for treatment of poststroke spasticity: a pooled-data analysis of three clinical trials

OBJECTIVE

The purpose of this study was to investigate the incidence of neutralizing antibody (NAb) formation in patients with poststroke spasticity treated with a specific formulation of botulinum toxin type A (BoNTA).

METHODS

Data from 3 previous clinical trials of BoNTA in patients with upper and/or lower limb spasticity were pooled and evaluated. Study 1 was a randomized, double-blind, placebo-controlled, multicenter trial of BoNTA in patients aged >/=21 years who had experienced a stroke >6 months before the initiation of the study. Study 2 was an open-label extension of study 1. Study 3 was a randomized, double-blind, multicenter trial of a specific BoNTA formulation in patients aged >/= 21 years who had experienced a stroke >/=6 weeks before study entry. Patients with a fixed contracture of the studied limb were excluded from participation in studies 1 and 2. Serum samples were obtained from each patient before each BoNTA treatment and at the end of each study. The mouse protection assay (MPA) was used for detection of NAbs to BoNTA in serum.

RESULTS

A total of 235 individual patients with post-stroke spasticity were enrolled in the 3 trials, including 126, 111 (all of whom participated in study 1), and 109 in studies 1, 2, and 3, respectively. Study 1 had an equal (50.0%) distribution of male and female patients (63/63). The distribution of male and female patients was 56 (50.5%) and 55 (49.5%), respectively, in study 2, and 55 (50.5%) and 54 (49.5), respectively, in study 3. The mean (SD) ages of patients in studies 1, 2, and 3 were 61.4 (13.8), 61.5 (14.1), and 58.5 (13.9) years, respectively. The MPA was used for detection of NAbs to BoNTA in the serum samples of 191 patients, including 64 from study 1, 111 from study 2 (55 of these patients were placebo recipients and 56 received their first BoNTA injection in study 1), and 72 (a sample was not obtained for 1 patient who had not received an injection) from study 3. The median number of BoNTA treatments received by these patients was 2 (range, 1-4 treatments) over a period lasting from 12 to 42 weeks. The mean dose of BoNTA was 241 U (range, 100-400 U), with a maximum dose of 960 U in any 1 patient. NAbs to BoNTA were detected in the serum sample of 1/191 (0.5%) patient who had participated in studies 1 and 2. Based on muscle-tone scores (3 and 4 for wrist and fingers, respectively) on a 5-point Ashworth Scale (0 = none to 4 = severe), the patient did not appear to exhibit a clinical response to BoNTA at any time during the studies.

CONCLUSION

Formation of NAbs was rare (1/191) in this group of adults with poststroke spasticity from three 12- to 42-week clinical trials who received >/=1 treatment with a specific BoNTA formulation at doses ranging from 100 to 400 U.

A risk-based bioanalytical strategy for the assessment of antibody immune responses against biological drugs

Bioanalytical assessments of anti-drug antibodies (ADAs) provide an understanding of the immunogenicity of biological drug molecules. The potential to induce ADAs after treatment with biologics is a safety issue that has become an important consideration in the development of biologics and a critical aspect of regulatory filings. US and European regulatory agencies are recommending that sponsors study immunogenicity using a risk-based approach, encouraging sponsors to formulate and implement their own risk management plans and to conduct discussions with the agencies when necessary. It follows from this that the greater the safety risks of ADAs, the more diligently one should clarify the immunogenicity of the product. Here we propose a general strategy to broadly assign immunogenicity risk levels to biological drug products, and present risk level-based 'fit-for-purpose' bioanalytical schemes for the investigations of treatment-related ADAs in clinical and nonclinical studies.

Safety and efficacy of botulinum toxin type A following long-term use

Botulinum toxin serotype A (BoNT-A) has long heritage of use leading to confidence in its safety and efficacy. The application of BoNT-A does not lead to persistent histological changes in the nerve terminal or the target muscle. Clinical trials defined the safety and tolerability profile of BoNT-A across common therapeutic indications and showed an incidence of adverse events of approximately 25% in the BoNT-A-treated group compared with 15% in the control group. Focal weakness was the only adverse event to occur more often following BoNT-A treatment. Long-term BoNT-A administration has been assessed in various treatment settings, with the level and duration of BoNT-A efficacy response being maintained over repeated rounds of injection with no major safety concerns. The treatment of children with cerebral palsy often require long-term, repeated, multimuscle BoNT-A injections that lead to the administration of comparably higher toxin doses. Despite the high total body doses used, their distribution over multiple muscles and injection sites means that systemic side effects are rare. Recent formulation changes have reduced the incidence of antibody development following treatment with BOTOX. These findings show long-term BoNT-A treatment to be both safe and efficacious for a wide variety of indications.

Botulinum Toxin in Ophthalmology

Since its introduction into clinical medicine in 1980, botulinum toxin has become a major therapeutic drug with applications valuable to many medical sub-specialties. Its use was spearheaded in ophthalmology where its potential applications have expanded to cover a broad range of visually related disorders. These include dystonic movement disorders, strabismus, nystagmus, headache syndromes such as migraine, lacrimal hypersecretion syndromes, eyelid retraction, spastic entropion, compressive optic neuropathy, and, more recently, periorbital aesthetic uses. Botulinum toxin is a potent neurotoxin that blocks the release of acetylcholine at the neuromuscular junction of cholinergic nerves. When used appropriately it will weaken the force of muscular contraction, or inhibit glandular secretion. Recovery occurs over 3 to 4 months from nerve terminal sprouting and regeneration of inactivated proteins necessary for degranualtion of acetylcholine vesicles. Complications are related to chemodenervation of adjacent muscle groups, injection technique, and immunological mechanisms.

European consensus table 2006 on botulinum toxin for children with cerebral palsy

An interdisciplinary group of experienced botulinum toxin users and experts in the field of movement disorders was assembled, to develop a consensus on best practice for the treatment of cerebral palsy using a problem-orientated approach to integrate theories and methods. The authors tabulated the supporting evidence to produce a condensed but comprehensive information base, pooling data and experience from nine European countries, 13 institutions and more than 5500 patients. The consensus table summarises the current understanding regarding botulinum toxin treatment options in children with CP.

Production of anti-neurotoxin antibody is enhanced by two subcomponents, HA1 and HA3b, of Clostridium botulinum type B 16S toxin–haemagglutinin

Clostridium botulinum type B strain produces two forms of progenitor toxin, 16S and 12S. The 12S toxin is formed by association of a neurotoxin (NTX) and a non-toxic non-haemagglutinin (NTNH), and the 16S toxin is formed by conjugation of the 12S toxin with a haemagglutinin (HA). HA consists of four subcomponents designated HA1, HA2, HA3a and HA3b. When mice were immunized with formalin-detoxified NTX, 12S or 16S, a significantly greater amount of anti-NTX antibody (Ab) was produced in the mice injected with 16S than in NTX- or 12S-injected mice. Immunization with NTX mixed with HA1 and/or HA3b also increased the anti-NTX Ab production, whereas NTX mixed with HA2 did not, indicating that HA1 and HA3b have adjuvant activity. This was further confirmed by immunizing mice with human albumin (Alb) alone or Alb mixed with either HA1 or HA3b. When mouse-spleen cells were stimulated with NTX, 16S or different HA subcomponents, 16S, HA1, HA3b and the mixture of HA1 and HA3 significantly increased interleukin 6 (IL6) production compared with NTX alone. Transcription of IL6 mRNA was low after stimulation with NTX alone, but increased to 16S-stimulation levels when NTX was mixed with HA1 or HA3b. In flow cytometry using labelled Abs against CD3 and CD19, the percentage of CD19 cells was higher following stimulation with 16S or NTX mixed with HA1 or HA3b compared with stimulation with NTX. The percentage of CD3 cells remained unchanged. These results suggest strongly that HA1 and HA3b demonstrate adjuvant activity via increasing IL6 production.

Endoscopic pyloric injection of botulinum toxin A for the treatment of refractory gastroparesis

BACKGROUND

Botulinum toxin A injected into the pyloric sphincter has been reported in small case series to treat gastroparesis. This study reviews the use of this treatment in a large number of patients with gastroparesis.

METHODS

Patients who underwent pyloric botulinum injection for treatment of gastroparesis were identified. Response was defined as improvement or resolution of the patient's major symptom and/or two minor symptoms for 4 weeks.

RESULTS

Of 115 patients treated, 63 patients met the study criteria. There were 53 women, 10 men, mean age 42 years. Most patients (56%) had idiopathic gastroparesis. Twenty-seven of 63 (43%) patients experienced a symptomatic response to treatment. By stepwise logistic regression, male gender was associated with response to treatment (OR 3.27: 95% CI[1.31, 8.13], p = 0.01). Vomiting as a major symptom was associated with a lack of response (OR 0.16: 95% CI[0.04, 0.67], p = 0.01). Despite the association of male gender with response, the mean duration of response for those patients responding, with a minimum of 3 months' follow-up was 4.9 months (+/-2.7 months) for women and 3.5 months (+/-0.71 months) for men (p = 0.59). The corresponding medians and interquartile ranges (IQR) were 5 (IQR 3-6) for females and 3.5 (IQR 3-4) for males.

CONCLUSIONS

Of the patients, 43% had a response to botulinum toxin treatment that lasted a mean of approximately 5 months. Male gender was associated with a response to this therapy; however, durability of response was unrelated to gender. Vomiting as a major symptom predicted no response.