DYSBOT: a single-blind, randomized parallel study to determine whether any differences can be detected in the efficacy and tolerability of two formulations of botulinum toxin type A--Dysport and Botox--assuming a ratio of 4:1

Patient-reported outcomes following a break in ophthalmic botulinum toxin therapy during the COVID-19 pandemic

OBJECTIVE

To evaluate the effect of a break in botulinum toxin treatment, necessitated by the COVID-19 pandemic, on patients' quality of life.

METHODS

Prospective cohort study of all patients undergoing incobotulinumtoxinA treatment in our department-for benign essential blepharospasm (BEB), hemifacial spasm (HFS), aberrant facial regeneration (AFR), or crocodile tears-who were affected by the break in service (March 18, 2020-June 17, 2020). All patients who received treatment both before and after the break in service were included. Data gathered included subjective patient-reported measure of "time until treatment failure" and disease rating scale scores: Blepharospasm-Dystonia Functional Disability Assessment Scale (BDFDAS; for BEB, HFS, and AFR); Jankovic Rating Scale (JRS; for BEB and HFS); and TEARS Epiphora Grading Scale (for crocodile tears).

RESULTS

Across 72 patients, there was a mean treatment delay of 3.9 months (range, 0-9.8 months). After a period of effect, treatment failed in all patients, with a mean time until treatment failure of 3.9 months (range, 0.5-12.0 months). All patient-reported outcome measurements increased, with greatest effect seen in AFR (178% increase in BDFDAS) and BEB (41% increase in JRS). At least 2 patients sought and underwent retreatment elsewhere in the private sector because of their symptom severity.

CONCLUSIONS

Patients with AFR and BEB are likely to tolerate a break in service least, whereas patients with crocodile tears appear to be less affected. This real-world snapshot allows quantification of the harm caused by a break in botulinum toxin service or a treatment delay. This study provides valuable information should further breaks in service or treatment delay be considered in the future due to a further wave of COVID-19 or other reasons.

Long-term follow-up of intravesical abobotulinumtoxinA (Dysport®) injections in women with idiopathic detrusor overactivity

Objective

Only a few numbers of studies have been published on the use of abobotulinumtoxinA (Dysport®) in idiopathic detrusor overactivity (IDO). This study reported the long-term follow-up of women with IDO who were treated with intravesical Dysport® injections.

Methods

Two hundred and thirty-six patients with IDO who had failed first-line conservative and antimuscarinic therapy received 500-900 units of Dysport® between April 2014 and July 2015. All patients were followed up for 5 years after their initial injection and interviewed on the phone.

Results

A total of 236 women with IDO aged from 18 years to 84 years (mean±standard deviation: 49.6±15.9 years) were included in our study. The median follow-up time for patients was 36.5 (range: 10-70) months, and the median recovery time after injection was 18.5 (range: 0-70) months. A total of 83 (35.2%) patients stated that they had subjective improvement of their symptoms whereas 84 (35.6%) patients did not report any improvement in symptoms. The initial International Consultation on Incontinence Questionnaire Overactive Bladder mean score was 6.9 (standard deviation 3.4). There was a positive association between the median recovery time and the components of the International Consultation on Incontinence Questionnaire Overactive Bladder questionnaire.

Conclusion

In a sub-population of overactive bladder patients with IDO who have failed first-line therapy, a single intravesical Dysport® injection can resolve patient symptoms completely or reduce the symptoms to an acceptable level that can be controlled with antimuscarinics or re-injection on demands.

Daily Vibrotactile Stimulation Exhibits Equal or Greater Spasticity Relief Than Botulinum Toxin in Stroke

OBJECTIVE

To test the feasibility and efficacy of the VibroTactile Stimulation (VTS) Glove, a wearable device that provides VTS to the impaired limb to reduce spastic hypertonia.

DESIGN

Prospective 2-arm intervention study-including 1 group of patients who use Botulinum toxin (BTX-A) for spasticity and 1 group of patients who do not use BTX-A.

SETTING

Participants were recruited through rehabilitation and neurology clinics.

PARTICIPANTS

Patients with chronic stroke (N=20; mean age=54 years, mean time since stroke=6.9 years). Patients who were previously receiving the standard of care (BTX-A injection) were eligible to participate and started the intervention 12 weeks after their last injection.

INTERVENTION

Participants were instructed to use the VTS Glove for 3 hours daily, at home or during everyday activities, for 8 weeks.

MAIN OUTCOME MEASURES

Spasticity was assessed with the Modified Ashworth Scale and the Modified Tardieu Scale at baseline and then at 2-week intervals for 12 weeks. Primary outcomes were the difference from baseline and at week 8 (end of VTS Glove use) and week 12 (4 weeks after stopping VTS Glove use). Patients who were receiving BTX-A were also assessed during the 12 weeks preceding the start of VTS Glove use to monitor the effect of BTX-A on spastic hypertonia. Range of motion and participant feedback were also studied.

RESULTS

A clinically meaningful difference in spastic hypertonia was found during and after daily VTS Glove use. Modified Ashworth and Modified Tardieu scores were reduced by an average of 0.9 (P=.0014) and 0.7 (P=.0003), respectively, at week 8 of daily VTS Glove use, and by 1.1 (P=.00025) and 0.9 (P=.0001), respectively, 1 month after stopping VTS Glove use. For participants who used BTX-A, 6 out of 11 showed greater change in Modified Ashworth ratings during VTS Glove use (mean=-1.8 vs mean=-1.6 with BTX-A) and 8 out of 11 showed their lowest level of symptoms during VTS Glove use (vs BTX-A).

CONCLUSIONS

Daily stimulation from the VTS Glove provides relief of spasticity and hypertonia. For more than half of the participants who had regularly used BTX-A, the VTS Glove provided equal or greater symptom relief.

Clinical Application of Botulinum Toxin for Hemifacial Spasm

Hemifacial spasm is typically caused by contact between the facial nerve and blood vessels. Microvascular decompression, a treatment that directly addresses this pathogenesis, is often considered the most effective treatment method. However, surgery is not immediately performed for patients at risk from the surgical treatment, or for those with an unclear diagnosis. In these instances, Botulinum toxin injection can help manage the patient's symptoms. Numerous studies corroborate the effectiveness and safety of Botulinum toxin treatment, with large-scale studies indicating symptom control lasts, on average, around 15 weeks.

The translational implications of the science behind the overactive bladder and the role of OnabotulinumtoxinA

Urinary incontinence (UI) is a very common condition that can affect patients of all ages and the commonest cause is an overactive bladder (OAB). Most patients with OAB were treated with pharmacotherapy and major surgery. Over 25 years ago, Dasgupta, Fowler et al. studied the presence and role of C fibres in the human bladder which are highly sensitive to capsaicin, the active ingredient of chillies. When capsaicin was instilled into patients' bladders as a synthetic solution, it was found to be highly effective in some patients. Capsaicin was later replaced by Resiniferatoxin. Both toxins desensitised C-fibres through the capsaicin receptor, TRPV1, without any lasting damage to the bladder itself. The discovery of botulinum toxin and its use in the treatment of OAB represents a major breakthrough, in the treatment of OAB. Another key innovation was the development of technique to administer the drug under local anaesthesia which allowed numerous patients to benefit from treatment who would otherwise have been precluded because of the need for injection under general anaesthetic. After extensive trials over many years Botox (OnabotulinumtoxinA) is now licensed for use in OAB. Compared to other treatments for overactive bladder, OnabotulinumtoxinA is more cost-effective and less invasive. It is thought to have changed the quality of life of an estimated 5 million patients worldwide.

[Therapy of Hemifacial Spasm with Botulinum Toxin: an Update]

Injections of botulinum toxin can be viewed by now as the therapy of choice in treating hemifacial spasm (HFS). Each of the three botulinum toxin-A preparations have been approved for this indication in Germany. HFS is a frequent disease characterized by involuntary contractions of the muscles of one half of the face innervated by the facial nerve. The symptoms can be either tonic or clonic, intermittant or permanent. Diagnosis is based purely on clinical observation. A magnetic resonance imagingof the skull is appropriate to demonstrate nerve-vessel contact as most frequent cause and to exclude other pathologies.

Botulinum Toxin for the Treatment of Hemifacial Spasm: An Update on Clinical Studies

Hemifacial spasm (HFS) is a movement disorder characterized by involuntary contractions of the facial muscles innervated by the seventh cranial nerve. Generally, it is associated with a poor quality of life due to social embarrassment and can lead to functional blindness. Moreover, it is a chronic condition, and spontaneous recovery is rare. Intramuscular injections of Botulinum Toxin (BoNT) are routinely used as HFS treatment.

METHODS

We reviewed published articles between 1991 and 2021 regarding the effectiveness and safety of BoNT in HFS as well as any reported differences among BoNT formulations.

RESULTS

The efficacy of BoNT for HFS treatment ranged from 73% to 98.4%. The mean duration of the effect was around 12 weeks. Effectiveness did not decrease over time. Adverse effects were usually mild and transient. The efficacy and tolerability of the different preparations appeared to be similar. Among the studies, dosage, injected muscles, intervals of treatment, and rating scales were variable, thus leading to challenges in comparing the results.

CONCLUSIONS

BoNT was the treatment of choice for HFS due to its efficacy and safety profile. Further studies are needed to investigate the factors that influence the outcome, including the optimal timing of treatment, injection techniques, dosage, and the best selection criteria for formulations.

Long-term stable efficacy of botulinum toxin A in facial movement disorders with no need for increasing dose

Botulinum toxin A is considered an effective treatment for involuntary facial movements. We examined whether treatment efficacy maintained or changed over time with two products, Botox and Dysport, in patients with hemifacial spasm, facial synkinesis and benign essential blepharospasm.We retrospectively investigated 87 consecutive patients (51 women, 36 men) who had undergone treatment for ≥6 years. Long-term effects, as well as side effects of Botox or Dysport local injections were evaluated. The first three treatments were considered the titration period and not taken into account when testing for dose changes.Mean treatment duration was 10 years (range 6-11, SD 1.0), 2441 treatments were administered, 1162 with Botox and 1279 with Dysport, the two brands were interchanged as needed. Good to full improvement was seen in 90% of patients both with both brands. Injection doses and treatment responses were consistent during the study with both drugs. No major side effects were reported, and relatively few minor adverse events were reported, with clear reduction from the titration period (6.1%), to the remainder of the study (3.9%).Botulinum toxin (BTX-A) is a satisfactory long-term treatment without need for dose increase over. Both Botox and Dysport were effective when used interchangeably.

Hemifacial spasm through the last three decades: From etiology to efficacy and safety of long-term botulinum toxin treatment

BACKGROUND

Hemifacial spasm (HFS) is an uncommon movement disorder characterized by involuntary contractions of muscles innervated by the facial nerve. The aim of this study is to analyze the etiology of HFS as well as the efficacy and safety of long-term botulinum toxin type A (BTX-A) treatment.

METHODS

Retrospective study including 125 patients with HFS treated with BTX-A from 1993 to 2019. Demographic and etiological variables as well as doses, number of sessions of BTX-A, infiltrated muscles, therapeutic response according to Patient Global Impression of Change Scale (PGIC-S), side effects and adjuvant treatments were analyzed. In addition, these variables were compared according to the etiology (idiopathic versus secondary).

RESULTS

92 patients (73.6%) were women and the mean age at diagnosis was 58.63 years (SD 15.4). The etiology was idiopathic in 79 patients (63.2%), 17.6% were secondary to Bell's palsy, 14.4% to vascular compression and 2.4% to tumors. A higher total dose per session was observed in the secondary group. PGIC-S showed a good response in 96% of cases. 16 patients (12.8%) required pharmacological concomitant treatment. 59 patients (47.2%) developed side effects. Transient eyelid ptosis and facial weakness were the most common.

CONCLUSIONS

The structural origin of a significant number of cases of HFS makes essential to complete an etiological diagnosis in all patients. In addition, the existence of a secondary cause could be associated with greater doses of BTX-A to achieve a good response. Regardless the etiology, long-term treatment with BTX-A in HFS is safe and effective.

Botulinum toxin type A therapy for blepharospasm

BACKGROUND

This is an update of a Cochrane Review first published in 2005. Blepharospasm is the second most common form of focal dystonia. It is a disabling disorder, characterised by chronic, intermittent or persistent, involuntary eyelid closure, due to spasmodic contractions of the orbicularis oculi muscles. Currently, botulinum toxin type A (BtA) is considered the first line of therapy for this condition.

OBJECTIVES

To compare the efficacy, safety, and tolerability of BtA versus placebo in people with blepharospasm.

SEARCH METHODS

We searched Cochrane Movement Disorders' Trials Register, CENTRAL, MEDLINE, Embase, reference lists of included articles, and conference proceedings. We ran all elements of the search, with no language restrictions, in July 2020.

SELECTION CRITERIA

Double-blind, parallel, randomised, placebo-controlled trials (RCTs) of BtA versus placebo in adults with blepharospasm.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed records, selected included studies, extracted data using a paper pro forma, and evaluated the risk of bias. We resolved disagreements by consensus, or by consulting a third review author. We performed meta-analyses using a random-effects model, for the comparison of BtA versus placebo, to estimate pooled effects and corresponding 95% confidence intervals (95% CI). We did not carry out any prespecified subgroup analyses. The primary efficacy outcome was improvement on any validated symptomatic rating scale. The primary safety outcome was the proportion of participants with any adverse event.

MAIN RESULTS

We included three RCTs, assessed at low to moderate overall risk of bias, which randomised 313 participants with blepharospasm. Two studies excluded participants with poorer prior responses to BtA treatment, therefore, they included an enriched population with a higher probability of benefiting from this therapy. All trials were industry-funded. All RCTs evaluated the effect of a single BtA treatment session. BtA resulted in a moderate to large improvement in blepharospasm-specific severity, with a reduction of 0.93 points on the Jankovic Rating Scale (JRS) severity subscale at four to six weeks after injection (95% confidence interval (CI) 0.61 to 1.25; I² = 9%) compared to placebo. BtA was also resulted in a moderate to large improvement in blepharospasm-specific disability and blepharospasm-specific involuntary movements at four to six weeks after injection (disability: 0.69 JRS disability subscale points, 95% CI 0.18 to 1.19; I² = 74%; blepharospasm-specific involuntary movements: standardised mean difference (SMD) 0.79, 0.31 to 1.27; I² = 58%) compared to placebo. BtA did not show a risk of adverse events (risk ratio (RR) 1.18, 95% CI 0.87 to 1.60; I² = 0%). However, BtA increased the risk of vision complaints and eyelid ptosis (vision complaints: RR 5.73, 95% CI 1.79 to 18.36; I² = 51%; eyelid ptosis: RR 4.02, 95% CI 1.61 to 10.00; I² = 39%). There was no distinction between BtA and placebo in the number of participants who dropped out of the trial. A single trial estimated the duration of effects to be 10.6 weeks (range 6.1 to 19.1). We found no evidence supporting the existence of a clear dose-response relationship with BtA. We found no data reporting the impact of BtA on health-related quality of life, or the development of secondary non-responsiveness.

AUTHORS' CONCLUSIONS

We are moderately certain that a single BtA treatment resulted in a clinically relevant reduction of blepharospasm-specific severity and disability, and have low certainty that it is well tolerated, when compared with placebo. There is low-certainty evidence that people treated with BtA are not at an increased risk of developing adverse events, though BtA treatment likely increases the risk of visual complaints and eyelid ptosis. There are no data from RCTs evaluating the effectiveness and safety of repeated BtA injection cycles. There is no evidence from RCTs to allow us to draw definitive conclusions on the optimal treatment intervals and doses, or the impact on quality of life.

Botulinum toxin type A therapy for hemifacial spasm

BACKGROUND

This is an update of a Cochrane Review, first published in 2005. Hemifacial spasm (HFS) is characterised by unilateral, involuntary contractions of the muscles innervated by the facial nerve. It is a chronic disorder, and spontaneous recovery is very rare. The two treatments routinely available are microvascular decompression and intramuscular injections with botulinum toxin type A (BtA).

OBJECTIVES

To compare the efficacy, safety, and tolerability of BtA versus placebo in people with HFS.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, reference lists of articles, and conference proceedings in July 2020. We ran the electronic database search, with no language restrictions, in July 2020.

SELECTION CRITERIA

Double-blind, parallel, randomised, placebo-controlled trials (RCTs) of BtA versus placebo in adults with HFS.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed records. We planned to select included studies, extract data using a paper pro forma, and evaluate the risk of bias. We resolved disagreements by consensus, or by consulting a third review author. We planned to perform meta-analyses. The primary efficacy outcome was HFS-specific improvement. The primary safety outcome was the proportion of participants with any adverse event.

MAIN RESULTS

We found no parallel-group randomised controlled trials comparing BtA and placebo in HFS.

AUTHORS' CONCLUSIONS

We did not find any randomised trials that evaluated the efficacy and safety of botulinum toxin type A in people with hemifacial spasm, so we are unable to draw any conclusions. Observational data show a strong association between BtA treatment and symptom improvement, and a favourable safety profile. While it is unlikely that future placebo-controlled RCTs will evaluate absolute efficacy and safety, they should address relevant questions for both people with HFS (such as long-term effects, quality of life, and other patient-reported outcomes), and clinicians (such as relative effectiveness of different BtA formulations and schemes of treatment) to better guide clinical practice.).

An Update on Botulinum Toxin in Neurology

Botulinum neurotoxin (BoNT) is an effective treatment for many neurologic disorders. This article gives a comprehensive overview of the clinical applications of BoNT across the field of neurology.

[Hemifacial spasm]

Hemifacial spasm (HFS), or facial hemispasm, is a paroxysmal hyperkinetic disorder involving muscles innervated by the facial nerve, mainly on the one hand. The development of HFS is based on neurovascular conflict. However, it is impossible to explain the clinical manifestations of HFS only by nerve compression. Both peripheral and central mechanisms are involved in the generation of HFS, with the formation of ephaptic transmission, antidromic excitation, primary or secondary hyper-excitability of the nuclear and supranuclear level of innervation. Two treatment methods are pathogenetically justified: microvascular decompression (MVD) and botulinum toxin (BTX) injections. The effectiveness of MVD is 95.37% with full or partial recovery. The recurrence rate does not exceed 2.4%. Facial nerve paralysis (2.7-22.5%) and hearing loss (1.9-20%) are the most common complications of treatment with the use of the MVD for HFS with partial or complete cure in most cases. Botulinum toxin injection chemo-denervation is a first-line treatment of primary and secondary HFS. HFS is an officially registered indication for the drug dysport (abobotulotoxin) (ABO) in the Russian Federation. Total doses of ABO ranged from 25 to 150 units for one side depending on the severity of the clinical manifestations. Studies demonstrate the statistically significant benefits of HFC treatment with ABO. ABO is generally well-tolerated. Adverse events (up to 3.6%) are transient and include ptosis, lacrimation, blurred vision, double vision, dry eyes and weak facial muscles.

Switchover study of onabotulinumtoxinA to incobotulinumtoxinA for facial dystonia

IMPORTANCE

When making a cost-saving it is important to ensure there is no loss of efficacy.

BACKGROUND

Clinical effectiveness and efficiency of incobotulinumtoxinA compared to onabotulinumtoxinA in facial dystonia is unclear. Our aim is to evaluate switching from onabotulinumtoxinA to incobotulinumtoxinA in the treatment of essential blepharospasm (EB), hemifacial spasm (HFS) and aberrant facial nerve regeneration (AFR).

DESIGN

A retrospective study of a prospective, single-masked switchover audit from onabotulinumtoxinA to incobotulinumtoxinA.

PARTICIPANTS

Twenty essential EB, 12 HFS and six AFR patients.

METHODS

A switchover from stable onabotulinumtoxinA to incobotulinumtoxinA using a 1:1 unit ratio and contemporaneous efficacy measures. Two nurse injectors performed the injections over a period of 6 years. Each masked patient received three onabotulinumtoxinA and three incobotulinumtoxinA over a minimum of 2 years.

MAIN OUTCOME METHODS

At each visit, a blepharospasm disability score (BDS), Jankovic score (JS), subjective improvement (SI), duration of maximum effect (DME) and complications were recorded. A cost comparison per unit dose was made.

RESULTS

Twenty EB, 12 HFS and six AFR received 114 onabotulinumtoxinA and 114 incobotulinumtoxinA treatments. Both brands had similar efficacy, but SI (P < .01) and DME (P < .05) were higher in the HFS group with incobotulinumtoxinA. Complications included bruising (two onabotulinumtoxinA, one incobotulinumtoxinA) and ptosis (three onabotulinumtoxinA, zero incobotulinumtoxinA). OnabotulinumtoxinA was 33% pricier.

CONCLUSION AND RELEVANCE

Switching from onabotulinumtoxinA to incobotulinumtoxinA did not result in an inferior outcome for the treatment of facial dystonia and led to a cost-saving for the department.

FDA Approvals and Consensus Guidelines for Botulinum Toxins in the Treatment of Dystonia

In 2016, the American Academy of Neurology (AAN) published practice guidelines for botulinum toxin (BoNT) in the treatment of blepharospasm, cervical dystonia, adult spasticity, and headache. This article, focusing on dystonia, provides context for these guidelines through literature review. Studies that led to Food and Drug Administration (FDA) approval of each toxin for dystonia indications are reviewed, in addition to several studies highlighted by the AAN guidelines. The AAN guidelines for the use of BoNT in dystonia are compared with those of the European Federation of the Neurological Societies (EFNS), and common off-label uses for BoNT in dystonia are discussed. Toxins not currently FDA-approved for the treatment of dystonia are additionally reviewed. In the future, additional toxins may become FDA-approved for the treatment of dystonia given expanding research in this area.

High Dosage of Botulinum Toxin Type A in Adult Subjects with Spasticity Following Acquired Central Nervous System Damage: Where Are We at?

Spasticity is a common disabling disorder in adult subjects suffering from stroke, brain injury, multiple sclerosis (MS) and spinal cord injury (SCI). Spasticity may be a disabling symptom in people during rehabilitation and botulinum toxin type A (BTX-A) has become the first-line therapy for the local form. High BTX-A doses are often used in clinical practice. Advantages and limitations are debated and the evidence is unclear. Therefore, we analysed the efficacy, safety and evidence for BTX-A high doses. Studies published from January 1989 to February 2020 were retrieved from MEDLINE/PubMed, Embase, Cochrane Central Register. Only obabotulinumtoxinA (obaBTX-A), onabotulinumtoxinA (onaBTX-A), and incobotulinumtoxinA (incoBTX-A) were considered. The term “high dosage” indicated ≥ 600 U. Thirteen studies met the inclusion criteria. Studies had variable method designs, sample sizes and aims, with only two randomised controlled trials. IncoBTX-A and onaBTX-A were injected in three and eight studies, respectively. BTX-A high doses were used predominantly in treating post-stroke spasticity. No studies were retrieved regarding treating spasticity in MS and SCI. Dosage of BTX-A up to 840 U resulted efficacious and safety without no serious adverse events (AEs). Evidence is insufficient to recommend high BTX-A use in clinical practice, but in selected patients, the benefits of high dose BTX-A may be clinically acceptable.

Botulinum toxin in low urinary tract disorders - over 30 years of practice (Review)

Botulinum toxin is a substance produced by Clostridium Botulinum and is responsible for human botulism. This substance is a poison, a neurotoxin, but used in limited quantities it can be a cure for some diseases. It is well connected to a large variety of medical applications. The mechanism of action relies on blocking the acetylcholine at the neuromuscular junction, which blocks the transmission of the nervous impulse with secondary flaccid paralysis. In urology, its role in idiopathic overactive bladder and neurogenic bladder is well known. We performed a thorough review using PubMed and other databases, revising the mechanisms of botulinum toxin action in urologic pathology, treatment procedures and other options. Botulinum toxin is a well-studied substance with a large number of applications in medicine. In urologic pathology, overactive bladder and neurogenic bladder are backed by robust studies that support the therapeutic role of this substance. The toxin has multiple effects, such as inhibition of the nerve growth factor, blocking the bladder sensory afferent pathway and apoptotic effect on the prostate tissue, by inhibiting the substance P, altering the nociceptive pathways. Interstitial cystitis and other rare pathologies show promising results, but further studies are needed. The role of botulinum toxin in benign prostatic hyperplasia is still not elucidated.

Use of Botulinum Toxin in Ophthalmology

Botulinum toxin is an important treatment for many conditions in ophthalmology, including strabismus, nystagmus, blepharospasm, hemifacial spasm, spastic and congenital entropion, corneal exposure, and persistent epithelial defects. The mechanism of action of botulinum toxin for both strabismus and nystagmus is the neuromuscular blockade and transient paralysis of extraocular muscles, but when botulinum toxin is used for some forms of strabismus, a single injection can convey indefinite benefits. There are two unique mechanisms of action that account for the long-term effect on ocular alignment: (1) the disruption of a balanced system of agonist-antagonist extraocular muscles and (2) the reestablishment of central control of alignment by the binocular visual system. For other ocular conditions, botulinum toxin acts through transient paralysis of periocular muscles. Botulinum toxin is a powerful tool in ophthalmology, achieving its therapeutic effects by direct neuromuscular blockade of extraocular and periocular muscles and by unique mechanisms related to the underlying structure and function of the visual system.

Comparison of Safety and Efficacy of Botox and Neuronox in the Management of Benign Essential Blepharospasm: A Split-face Study

Purpose

To compare the efficacy and safety of Botox and Neuronox in the management of benign essential blepharospasm (BEB).

Methods

We performed a triple-masked, randomized control study to compare Botox and Neuronox in 48 eyes of 24 patients with BEB. All 24 patients randomly received Botox or Neuronox in the periorbital region in a masked, randomized split-face manner, keeping the injection sites and doses uniform. The toxin preparation, injection, and clinical evaluations were done by three independent observers. Objective outcome measures included improvement in the severity of spasm, grading of the functional visual status, changes in palpebral fissure height, lagophthalmos, superficial punctate keratitis and Schirmer's test at 2 weeks, 6 weeks, and upon conclusion of the effect of the toxin. Subjective outcome measures included duration of the effect and a forced choice stating which half of the face was better. Evaluations were performed through clinical measurements, external digital photography, and high-definition videography.

Results

The mean duration of relief from spasms was 3.78 months (standard deviation, 1.58 months; range, 1 to 6 months). The improvement in the objective parameters like severity of spasm and functional visual status was statistically significant at the 2-week and 6-week follow-up visits (p < 0.001). The changes in palpebral fissure height, lagophthalmos, and superficial punctate keratitis were equally observed in both groups. At 2 and 6 weeks, three of 24 (12.5%) and one of 24 (4%) patients, respectively, reported an unequal effect between the two sides of the face, but this difference was not statistically significant. At final follow-up (conclusion of the toxin effect), patients reported equal effect with no preference for either hemiface. No statistically significant differences were found in the comparative analysis between the Neuronox and Botox groups.

Conclusions

Neuronox and Botox are comparable in terms of their safety and efficacy in the management of BEB.

Use of botulinum toxin for movement disorders

The term movement disorders encompasses all disorders hypokinetic and hyperkinetic, which were previously known as extrapyramidal syndromes. With the definition of movement disorders and their diagnostic criteria and classifications, new studies for therapeutics could be performed. New drugs were launched, functional neurosurgery was developed, and the introduction of botulinum toxin (BoNT) for hyperkinesias was introduced. BoNT is an important therapy for dystonia, tics, myoclonus, and tremors. The aim of this review is to present the new and well-established uses of BoNT for movement disorders.

Progress in Applying the Three Rs to the Potency Testing of Botulinum Toxin Type A

Botulinum toxin type A (BTA) is being increasingly used for a range of therapeutic purposes and also for cosmetic reasons. For many years, the potency of BTA has been measured by using an LD50 assay in mice. This assay is a cause for concern due to its unpleasant nature and extreme severity, and the requirement for high numbers of mice to be used. Alternatives to this potency assay are presently reviewed with particular reference to the work at the National Institute for Biological Standards and Control (NIBSC), and to recent work by the UK manufacturer of the substance. An in vivo local paralysis assay with considerably less severity has been developed and is in use at the NIBSC. Alternative, ex vivo functional assays in use include the measurement of BTA-induced paralysis of neurally-stimulated rodent diaphragm or rat intercostal muscle. The latter method has the advantage of allowing more preparations to be derived from one animal. However, these ex vivo methods have not yet been fully validated and accepted by regulatory agencies as potency assays. Endopeptidase assays, although not measuring muscle paralysis directly, may provide a very useful consistency test for batch release and may replace the routine use of the LD50 test for that purpose. These assays measure the cleavage of the SNAP-25 protein (the final stage of BTA action), and have been validated for batch release by the National Control Laboratory (NIBSC), and are in regular use there. ELISA assays, used alongside the endopeptidase assay, also provide useful confirmatory information on the amounts of functional (and non-functional) BTA present. The UK manufacturer is further validating its endopeptidase assay, an ex vivo muscle assay and an ELISA. It is anticipated that their work will lead to a change in the product license, hopefully within the next two years, and will form a critical milestone towards the end of the LD50 potency test.

Pharmacological differences and clinical implications of various botulinum toxin preparations: a critical appraisal

Three different type A botulinum neurotoxins (BoNTAs) - onabotulinumtoxinA, abobotulinumtoxinA and incobotulinumtoxinA) - are currently marketed in Europe to treat several conditions. Differences between BoNTA preparations, which depend on their specific biotypes and manufacturing processes, lead to clinically relevant pharmacotherapeutic dissimilarities. All three available products are separately recognized and reviewed in American Academy of Neurology guidelines. The neurotoxin load/100U is likewise different among the different BoNTAs, with the result that the specific potency of the 150kD BoNTA neurotoxin is calculated as 137 units/ng for onabotulinumtoxinA, 154 units/ng for abobotulinumtoxinA, and 227 units/ng for incobotulinumtoxinA. It is important for clinicians to have all three BoNTAs available in order to choose the most suitable preparation for the specific indication in the single patient. Commercially available BoNTAs must be recognized as different from one another, and therefore as non-interchangeable. The essential experience of the clinician is of the utmost importance in choosing the most appropriate treatment.

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.

Chemodenervation for the Treatment of Facial Dystonia: A Report by the American Academy of Ophthalmology

PURPOSE

To review the medical literature on the outcomes and complications of various Food and Drug Administration-approved botulinum toxins for benign essential blepharospasm (BEB) and hemifacial spasm (HFS).

METHODS

Literature searches were last conducted in February 2017 in PubMed for articles published in English and in the Cochrane Library database without language limitations; studies published before 2000 were excluded. The combined searches yielded 127 citations. Of these, 13 articles were deemed appropriate for inclusion in this assessment, and the panel methodologist assigned ratings to them according to the level of evidence.

RESULTS

A combined total of 1523 patients (1143 with BEB and 380 with HFS) were included in the 13 studies. Five studies provided level I evidence, 2 studies provided level II evidence, and 6 studies provided level III evidence. Pretarsal injections were more efficacious than preseptal injections (96% vs. 86%, respectively). Pretarsal injections also resulted in a higher response rate on clinical scales (P < 0.05) and a longer duration of maximum response for both HFS and BEB. Patients with HFS require lower overall doses of onabotulinumtoxinA than patients with BEB for a similar duration of effect. Adverse events were dose related, and they occurred more frequently in patients who were given more units.

CONCLUSIONS

Level I evidence supports the efficacy of Botox (Allergan Corp., Irvine, CA), Meditoxin, and Xeomin (Merz Pharmaceuticals, Frankfurt am Main, Germany) for the treatment of BEB. Meditoxin and Botox have equivalent effectiveness and incidence of adverse events for BEB and HFS. Dysport (Ipsen Biopharmaceuticals, Inc, Paris, France) seems to have efficacy similar to Botox and Meditoxin for BEB and HFS, but any definitive conclusions from the 2 level II studies in this review are limited by differences in the methodologies used. Higher doses of Botox and Dysport result in more adverse events. Repeated treatments using Botox seem to maintain efficacy for treatment of facial dystonias over a follow-up period of at least 10 years, based on level III evidence.

Botulinum Toxin Treatment of Movement Disorders

Botulinum neurotoxins (BoNTs) are now among the most widely used therapeutic agents in clinical medicine with indications applied to the fields of movement disorders, pain disorders, and autonomic dysfunction. In this literature review, the efficacy and utility of BoNTs in the field of movement disorders are assessed using the criteria of the Guideline Development Subcommittee of the American Academy of Neurology. The literature supports a level A efficacy (established) for BoNT therapy in cervical dystonia and a level B efficacy (probably effective) for blepharospasm, hemifacial spasm, laryngeal dystonia (spasmodic dysphonia), task-specific dystonias, essential tremor, and Parkinson rest tremor. It is the view of movement disorder experts, however, that despite the level B efficacy, BoNTs should be considered treatment of first choice for blepharospasm, hemifacial spasm, laryngeal, and task-specific dystonias. The emerging data on motor and vocal tics of Tourette syndrome and oromandibular dystonias are encouraging but the current level of efficacy is U (undetermined) due to lack of published high-quality studies.

Long-term Efficacy of Botulinum Neurotoxin-A Treatment for Essential Blepharospasm

Purpose

In the present study, we investigated the treatment efficacy and clinical outcomes of botulinum neurotoxin-A (BoNT-A) administered for longer than 5 years to patients with essential blepharospasm.

Methods

We retrospectively reviewed 19 patients (male : female = 8 : 11) diagnosed with essential blepharospasm between March 2006 and July 2016 who underwent BoNT-A injections for over 5 years and were followed. Efficacy of 297 injections of Botox (n = 162), Meditoxin (n = 75), Hugel-tox (n = 40), or Dysport (n = 20) was based on the symptom improvement score at the final injection (−1, worse; 0, same; 1, better). Injection dose (botox unit), duration of efficacy (months), and adverse events were also investigated.

Results

Based on product type, significant differences in patient age (59.3 ± 9.8 years), disease period (5.0 ± 5.4 years), number of botulinum neurotoxin injections before visiting our clinic (1.6 ± 2.6), and follow-up period (7.2 ± 1.6 years) were not observed. Treatment efficacy score and injection dose of repetitive injections were 0.1 ± 0.5 and 39.1 ± 4.0 units, respectively, and did not show significant differences with repeated injections. Duration of response was 5.9 ± 5.4 months, but this significantly decreased as the injections were repeated (p < 0.01). Among the 297 injections, adverse events occurred 12 times (4.0%) with no severe sequelae.

Conclusions

In this study, we showed that repetitive, long-term BoNT-A injections are considered a stable and effective treatment for essential blepharospasm in terms of consistent injection dose and maintenance of treatment efficacy. However, the duration of long-term efficacy could be decreased in patients injected repetitively.

Treatment of Blepharospasm/Hemifacial Spasm

OPINION STATEMENT

The treatment of both hemifacial spasm (HFS) and blepharospasm (BEB) requires making the appropriate clinical diagnosis. Advance imaging and electrophysiologic studies are useful; however, one's clinical suspicion is paramount. The purpose of this review is to summarize current and emerging therapies for both entities. Botulinum toxin (BTX) remains the first-line therapy to treat both conditions. If chemodenervation has failed, surgery may be considered. Due to the risks associated with surgery, the benefits of this option must be carefully weighed. Better surgical outcomes are possible when procedures are performed at tertiary centers with experienced surgeons and advanced imaging techniques. Microvascular decompression is an efficacious method to treat HFS, and myectomy is an option for medication-refractory BEB; the risks of the latter may outweigh any meaningful clinical benefits. Oral agents only provide short-term relief and can cause several unwanted effects; they are reserved for patients who cannot receive BTX and/or surgery. Transcranial magnetic stimulation has gained some traction in the treatment of BEB and may provide safer non-invasive options for refractory patients in the future.

Injectable and topical neurotoxins in dermatology: Basic science, anatomy, and therapeutic agents

Botulinum toxin is a potentially deadly anaerobic bacterial toxin that acts by inhibiting release of acetylcholine at the neuromuscular junction, thereby inhibiting contraction of the exposed striated muscle. There are currently 4 botulinum toxin preparations approved by the US Food and Drug Administration (FDA): onabotulinumtoxin, abobotulinumtoxin, incobotulinumtoxin and rimabotulinumtoxin. While significant overlap exists, each product has unique properties and specifications, including dosing, diffusion, and storage. Extensive physician knowledge of facial anatomy, coupled with key differences of the various neurotoxin types, is essential for safe and successful treatments. The first article in this continuing medical education series reviews key characteristics of each neurotoxin, including new and upcoming agents, and provides an anatomic overview of the most commonly injected cosmetic sites.

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

History of Botulinum Toxin Treatment in Movement Disorders

BACKGROUND

The frontiers of clinical medicine constantly expand as a result of the innovative efforts of visionary researchers and keen observations of seasoned clinicians. In medicine, rarely has a therapeutic agent been found efficacious in the management of so many symptoms and in such a relatively short time as botulinum toxin. One of the most notable contributions of botulinum toxin therapy in clinical medicine is in the field of movement disorders.

METHODS

The English literature was searched using the Yale search engine including but not limited to PubMed and Ovid. The search includes articles from January 1 1980 to March 1 2016.

RESULTS

A total of 2055 articles were identified. Of these, 132 met the criteria for this review.

DISCUSSION

This historical review highlights early and seminal contributions that have introduced the application of botulinum toxins in the field of movement disorders and provides evidence-based contributions that have established botulinum toxin as an effective treatment for abnormal movements.

A Comparison of Botox 100 U/mL and Dysport 100 U/mL Using Dose Conversion Ratio 1: 3 and 1: 1.7 in the Treatment of Cervical Dystonia: A Double-Blind, Randomized, Crossover Trial

OBJECTIVES

Intramuscular injections of botulinum toxin (BTX) are used as symptomatic treatment for cervical dystonia. Botox and Dysport are commercial products containing BTX; however, dosage and concentration of the prepared solution vary considerably among studies. The concentration of BTX in the prepared solution affects clinical outcome. This double-blind, randomized crossover trial compares Botox and Dysport in 2 different dose conversion ratios (1:3 and 1:1.7) when diluted to the same concentration (100 U/mL).

METHODS

Forty-six patients with cervical dystonia received 3 different treatments, Botox in 2 different doses and Dysport as control treatment. The efficacy was evaluated 4 and 12 weeks after treatment using 5 instruments, including Toronto Western Spasmodic Torticollis Rating Scale.

RESULTS AND CONCLUSION

The primary outcome was the estimated median Toronto Western Spasmodic Torticollis Rating Scale total score, which was 1.96 points higher for Botox (1:3) compared with Dysport at week 4, but the difference was not statistically significant (confidence interval, -0.88-4.61; P = 0.0799). No significant differences were seen between Botox (1:1.7) and Dysport. At week 12, a statistically significant difference in effect between Botox (1:3) and Dysport was observed, suggesting a shorter duration of effect for Botox when this ratio (low dose) was used. Furthermore, the patients' assessments showed that the ratio 1:3 resulted in suboptimal efficacy of Botox. These secondary outcome observations indicate that the dose conversion ratio between Dysport 100 U/mL and Botox 100 U/mL may be lower than 1:3, but this must be further validated in a larger patient material.

Use of Botulinum Toxin A in the Treatment of Lower Urinary Tract Disorders: A Review of the Literature

Botulinum neurotoxin (BoNT) is used to treat a variety of ailments, and its therapeutic application in lower urinary tract disorders (LUTDs) is well studied. Robust evidence supporting the efficacy and tolerability of BoNT in the treatment of neurogenic detrusor overactivity (NDO) and non-neurogenic overactive bladder (OAB) has led to regulatory approval for these conditions. Use of BoNT in the treatment of interstitial cystitis/bladder pain syndrome, chronic pelvic pain, and detrusor sphincter dyssynergia has demonstrated some promise, but is still evolving and off-label for these indications. Trials to date do not support the use of BoNT for benign prostatic hyperplasia. This comprehensive review outlines the mechanisms of BoNT in the treatment of LUTDs in adults and presents background and updated data examining the efficacy and adverse events associated with the use of BoNT in common urologic applications.

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.

Considerations on patient-related outcomes with the use of botulinum toxins: is switching products safe?

Introduction

Botulinum toxin (BoNT) is the treatment of choice for many neurologic movement disorders, including blepharospasm, hemifacial spasm, and cervical dystonia. There are two serotypes approved for use by the US Food and Drug Administration: three brands of serotype A and one of serotype B. Many attempts have been made at establishing dose conversion ratios between brands and serotypes. This review focuses on the existing data comparing different formulations of the same BoNT serotypes as well as that comparing different serotypes with one another. We focus on existing data regarding switching from one formulation or serotype to another and will also discuss the issue of immunogenicity of BoNT. With this information as a foundation, recommendations on safety of switching agents are addressed.

Method

Literature review searching PubMed and Google Scholar using the search terms “switching botox”, “dosing equivalency in botox”, and “comparing botox”.

Results/conclusion

Overall, there are many studies that demonstrate the efficacy and safety of each of the brands of BoNTs used in clinical practice. However, determination of dosing equivalencies among these brands and serotypes is complex with inconsistencies among the studies. When switching from one brand to another, the clinician should be aware of these issues, and not make the assumption that such ratios exist. Tailoring the dosage of each brand of BoNT to the clinical situation is the most prudent treatment strategy rather than focusing closely on conversion factors and concerns for immunogenicity.

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.

Botulinum neurotoxins for the treatment of focal dystonias: Review of rating tools used in clinical trials

Botulinum neurotoxins (BoNTs) are used to achieve therapeutic benefit in focal dystonia. An expert panel recently reviewed published evidence on the efficacy of BoNTs for the treatment of focal dystonias and produced recommendations for clinical practice. Another panel reviewed the clinimetric properties of rating scales for dystonia and produced recommendations for current usage and future directions. Considering that the strength of evidence derives not only from the quality of the study design, but also from usage of validated outcome measures, we combined the information provided by these two recent reviews and assessed the appropriateness of the rating instruments used in clinical trials on BoNT treatment in focal dystonia. Data sources included all the publications on BoNT treatment for focal dystonias reviewed by the recent evidence-based analysis. We reviewed all rating instruments used to assess primary and secondary outcome following BoNT treatment. The publications were allocated into five topics according to the focal dystonia type reviewed in the meta-analysis: blepharospasm, oromandibular dystonia, cervical dystonia, upper limb dystonia, and laryngeal dystonia. For each topic, papers were divided, according to the terminology used in the meta-analysis, into placebo-controlled, active comparator and methodological or uncontrolled. For each topic we identified the rating tools used in each study class and annotated which were the mostly used in each focal dystonia type. Outcome measures included tools related to motor and non-motor features, such as pain and depression, and functional as well as health-related quality of life features. Patient- and investigator-reported outcomes were also included. Rating instruments were classified as recommended, suggested, listed or not included, based on recommendations produced by the rating scale task force. Both primary and secondary outcome measures were assessed. As a final step we compared current practice, as summarized by the meta-analysis, with the recommendations of the rating scales panel. For blepharospasm, three placebo-controlled trials used suggested scales, one active-comparator study used a recommended scale and three active-comparator studies used suggested scales. For oromandibular dystonia, one placebo-controlled study used a suggested scale. For cervical dystonia, six placebo-controlled trials used a recommended scale, four active-comparator trials used a recommended scale and one active-comparator study used a suggested scale. For upper limb and laryngeal dystonia, no trial used validated instruments. Appropriately designed studies should be based on recommended rating instruments. Therapeutic trials not using clinimetrically tested rating measures do not provide sufficient information on efficacy of BoNT treatment, even if the study design is robust. Further research is needed to develop and validate new tools to assess all types of focal dystonia and to apply them in prospective placebo-controlled clinical trials.

Clinical differences between botulinum neurotoxin type A and B

In humans, the therapeutic use of botulinum neurotoxin A (BoNT/A) is well recognized and continuously expanding. Four BoNTs are widely available for clinical practice: three are serotype A and one is serotype B: onabotulinumtoxinA (A/Ona), abobotulinumtoxinA (A/Abo) and incobotulinumtoxinA (A/Inco), rimabotulinumtoxinB (B/Rima). A/Abo, A/Inco, A/Ona and B/Rima are all licensed worldwide for cervical dystonia. In addition, the three BoNT/A products are approved for blepharospasm and focal dystonias, spasticity, hemifacial spasm, hyperhidrosis and facial lines, with remarkable regional differences. These toxin brands differ for specific activity, packaging, constituents, excipient, and storage. Comparative literature assessing the relative safety and efficacy of different BoNT products is limited, most data come from reports on small samples, and only a few studies meet criteria of evidence-based medicine. One study compared the effects of BoNT/A and BoNT/B on muscle activity of healthy volunteers, showing similar neurophysiological effects with a dose ratio of 1:100. In cervical dystonia, when comparing the effects of BoNT/A and BoNT/B, results are more variable, some studies reporting roughly similar peak effect and overall duration (at a ratio of 1:66, others reporting substantially shorter duration of BoNT/B than BoNT/A (at a ratio 1/24). Although the results of clinical studies are difficult to compare for methodological differences (dose ratio, study design, outcome measures), it is widely accepted that: BoNT/B is clinically effective using appropriate doses as BoNT/A (1:40-50), injections are generally more painful, in most of the studies on muscular conditions, efficacy is shorter, and immunogenicity higher. Since the earliest clinical trials, it has been reported that autonomic side effects are more frequent after BoNT/B injections, and this observation encouraged the use of BoNT/B for sialorrhea, hyperhidrosis and other non-motor symptoms. In these indications the efficacy of toxins A and B are comparable and dose ratio is 1:25-30.

Botulinum toxin injections for the treatment of hemifacial spasm over 16 years

The aim of this study was to investigate the efficacy and side effects of botulinum toxin (BTX) in the treatment of hemifacial spasm (HFS). We also focused on the divergence between different injection techniques and commercial forms. We retrospectively evaluated 470 sessions of BTX injections administered to 68 patients with HFS. The initial time of improvement, duration and degree of improvement, and frequency and duration of adverse effects were analysed. Pretarsal and preseptal injections and Botox (Allergan, Irvine, CA, USA) and Dysport (Ipsen Biopharmaceuticals, Paris, France) brands were compared in terms of efficacy and side effects, accompanied by a review of papers which reported BTX treatment of HFS. An average of 34.5 units was used per patient. The first improvement was felt after 8 days and lasted for 14.8 weeks. Patients experienced a 73.7% improvement. In 79.7% of injections, no adverse effect was reported, in 4.9% erythema, ecchymosis, and swelling in the injection area, in 3.6% facial asymmetry, in 3.4% ptosis, in 3.2% diplopia, and in 2.3% difficulty of eye closure was detected. Patients reported 75% improvement on average after 314 sessions of pretarsal injections and 72.7% improvement after 156 sessions of preseptal injections (p=0.001). The efficacy and side effects of Botox and Dysport were similar. BTX is an effective and safe treatment option for HFS. No difference was determined between Botox and Dysport, and pretarsal injection is better than preseptal injection regarding the reported degree of improvement.

WITHDRAWN: Botulinum toxin for subacute/chronic neck pain

Withdrawn due to non‐compliance with The Cochrane Collaboration’s Commercial Sponsorship Policy

The editorial group responsible for this previously published document have withdrawn it from publication.

WITHDRAWN: Medicinal and injection therapies for mechanical neck disorders

Withdrawn due to non‐compliance with The Cochrane Collaboration’s Commercial Sponsorship Policy

The editorial group responsible for this previously published document have withdrawn it from publication.

Botulinum toxin in the management of blepharospasm: current evidence and recent developments

Blepharospasm is a focal (although usually bilateral) dystonia of the orbicularis oculi muscles, producing excessive eye closure. This produces significant disability through functional blindness. Botulinum neurotoxins (BoNT) have become the treatment of choice for blepharospasm; the impressive response rate and the tolerable safety profile have been proven through multiple clinical studies. There are currently four BoNT approved in the United States for different indications - we review the data on blepharospasm for each of these drugs. Currently, incobotulinumtoxinA and onabotulinumtoxinA have the most evidence of benefit for patients with blepharospasm. Current evidence, recent development and future directions are discussed.

Botulinum toxin type A products are not interchangeable: a review of the evidence

Botulinum toxin type A (BoNTA) products are injectable biologic medications derived from Clostridium botulinum bacteria. Several different BoNTA products are marketed in various countries, and they are not interchangeable. Differences between products include manufacturing processes, formulations, and the assay methods used to determine units of biological activity. These differences result in a specific set of interactions between each BoNTA product and the tissue injected. Consequently, the products show differences in their in vivo profiles, including preclinical dose response curves and clinical dosing, efficacy, duration, and safety/adverse events. Most, but not all, published studies document these differences, suggesting that individual BoNTA products act differently depending on experimental and clinical conditions, and these differences may not always be predictable. Differentiation through regulatory approvals provides a measure of confidence in safety and efficacy at the specified doses for each approved indication. Moreover, the products differ in the amount of study to which they have been subjected, as evidenced by the number of publications in the peer-reviewed literature and the quantity and quality of clinical studies. Given that BoNTAs are potent biological products that meet important clinical needs, it is critical to recognize that their dosing and product performance are not interchangeable and each product should be used according to manufacturer guidelines.