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

Current use of neurotoxins for alleviating symptoms of cervical dystonia

INTRODUCTION

Cervical dystonia (CD) causes involuntary movements and postures of the head, neck, and shoulders, as well as nonmotor symptoms including pain, mood, and sleep dysfunction, and impacts quality of life. The first-line treatment for CD is botulinum neurotoxin (BoNT) injections.

AREAS COVERED

The clinical presentation and diagnosis of CD, as well as where BoNT resides in the treatment landscape, is reviewed first. Next, the mechanism of action and the pharmacological differences in the available preparations of BoNT products are explained. The evidence base for motor and nonmotor efficacy and safety of the available BoNT formulations is reviewed, with attention to duration of benefit as a driver of patient satisfaction. Practical determinants of BoNT efficacy are reviewed including muscle selection, accurate muscle injection, factors related to poor or deteriorating response, and immunogenicity.

EXPERT OPINION

BoNT represents a significant advancement in the treatment of CD. More accurate diagnosis, muscle selection and targeting, and dosing can improve outcomes with existing BoNT formulations. Further refinement of BoNT potency, duration of action, safety, and immunogenicity will help reduce unmet needs in the magnitude and duration of benefit. Additional validation of DBS and MRI-guided focused ultrasound may expand options for patients with toxin nonresponse.

Update on Non-Interchangeability of Botulinum Neurotoxin Products

The growing use of botulinum neurotoxins (BoNTs) for medical and aesthetic purposes has led to the development and marketing of an increasing number of BoNT products. Given that BoNTs are biological medications, their characteristics are heavily influenced by their manufacturing methods, leading to unique products with distinct clinical characteristics. The manufacturing and formulation processes for each BoNT are proprietary, including the potency determination of reference standards and other features of the assays used to measure unit potency. As a result of these differences, units of BoNT products are not interchangeable or convertible using dose ratios. The intrinsic, product-level differences among BoNTs are compounded by differences in the injected tissues, which are innervated by different nerve fiber types (e.g., motor, sensory, and/or autonomic nerves) and require unique dosing and injection sites that are particularly evident when treating complex therapeutic and aesthetic conditions. It is also difficult to compare across studies due to inherent differences in patient populations and trial methods, necessitating attention to study details underlying each outcome reported. Ultimately, each BoNT possesses a unique clinical profile for which unit doses and injection paradigms must be determined individually for each indication. This practice will help minimize unexpected adverse events and maximize efficacy, duration, and patient satisfaction. With this approach, BoNT is poised to continue as a unique tool for achieving individual goals for an increasing number of medical and aesthetic indications.

Does ultrasound-guidance improve the outcome of botulinum toxin injections in cervical dystonia?

PURPOSE

Ultrasound-guided injections of botulinum neurotoxin in cervical dystonia have a number of theoretical advantages. However, their action has never been compared to that of non-guided injections. The objectives of the study were to compare the outcome of botulinum neurotoxin type A treatment in patients with idiopathic, focal cervical dystonia, according to two methods: inspection and palpation of anatomical landmarks (non-guided group) or ultrasound guidance (ultrasound-guided group).

METHODS

We included consecutive patients in this single-center, prospective, real-life, non-randomized study. The outcomes were evaluated one month after the injections: Cervical Dystonia Impact Profile 58 (main outcome), Toronto Western Spasmodic Torticollis Rating Scale-2 (pain and disability subscores), Toronto Western Spasmodic Torticollis Rating Scale-PSYCH, patient-rated Clinical Global Impression - Improvement and adverse events. We used propensity score methods for statistical analysis; ten predefined confounding factors were used to build the propensity score.

RESULTS

Sixty-three patients were included in the non-guided group, and 60 other patients in the ultrasound-guided group. We found no difference in main and secondary outcomes between the two study groups.

CONCLUSION

This is the first direct comparison between ultrasound-guided and non-guided botulinum neurotoxin type A injections in patients with cervical dystonia. We hypothesize that ultrasound guidance made it possible to obtain the same results in the most severe (or the most demanding) patients as in the best responders. Further studies are still needed to assess the impact of botulinum neurotoxin injections into deep cervical muscles.

Pain in cervical dystonia: mechanisms, assessment and treatment

INTRODUCTION

In patients with cervical dystonia (CD), pain is a major contributor to disability and social isolation and is often the main reason patients seek treatment. Surveys evaluating patient perceptions of their CD symptoms consistently highlight pain as a troublesome and disabling feature of their condition with significant impact on daily life and work.

AREAS COVERED

In this article, the authors review the epidemiology, assessment, possible mechanisms and treatment of pain in CD, including a meta-analysis of randomized controlled trial data with abobotulinumtoxinA.

EXPERT OPINION

Mechanisms of pain in CD may be muscle-based and non-muscle based. Accumulating evidence suggests that non-muscle-based mechanisms (such as abnormal transmission and processing of nociceptive stimuli, dysfunction of descending pain inhibitory pathways as well as structural and network changes in the basal ganglia, cortex and other areas) may also contribute to pain in CD alongside prolonged muscle contraction. Chemodenervation with botulinum toxin is considered the first-line treatment for CD. Treatment with botulinum toxin is usually effective, but optimization of the injection parameters should include consideration of pain as a core symptom in addition to the motor problems.

Dose conversion ratio, comparative efficacy, and adverse events after switching from onabotulinum toxin A to abobotulinum toxin A for neurological conditions

OBJECTIVES

Onabotulinum toxin A (ONA, Botox®) and abobotulinum toxin A (ABO, Dysport®) are most frequently used in the treatment of movement disorders. The aim of this study was to identify the dose conversion ratio (ABO dose:ONA dose), comparative efficacy, and adverse events in patients who switched from ONA to ABO.

METHODS

There were 64 patients with cervical dystonia (39), hemifacial spasm (16), oromandibular dystonia (5), blepharospasm (3), and extremity dystonia (1) who switched from ONA to ABO. The efficacy, adverse events, duration of action, and severity of the adverse events after the final dose of ONA, initial dose of ABO, and second dose of ABO were investigated in these patients.

RESULTS

The mean dose conversion ratio was 4.70 (2.27-9.62). The mean efficacy of the final ONA injection was 70.62%; initial ABO injection, 72.27%; and second ABO injection, 73.52%, which showed improvement on a visual analog scale (p = 0.71, p = 0.5). Incidence of adverse events after the final ONA injection was 18.8%; this increased to 39.1% after the initial ABO injection (p < 0.001) and decreased to 14.1% after the second ABO injection (p = 0.77). After the initial ABO injection, 20% of the adverse events were trivial, 36% were mild, and 32% were severe. After the second ABO injection, 7.8% of the adverse events were mild and 6.3% were severe.

CONCLUSION

Although the mean dose conversion ratio was 4.70, the range was very wide (approximately 2-9). Therefore, we conclude that after the switch from Botox to Dysport, the doses should be tailored to the patients' clinical situation at treatment initiation, without using a dose conversion ratio.

Factors Influencing the Surgical Decision in Dystonia Patients Referred for Deep Brain Stimulation

There is no available data on the journey of dystonia patients once referred to a tertiary center to undergo deep brain stimulation (DBS). We hypothesized that some patients might be incorrectly diagnosed while others might decline the procedure or experience significant benefit with switching to a different botulinum neurotoxin (BoNT). This is a single-center, retrospective study of dystonia patients who were referred to the DBS program between January 2014 and December 2018. We collected data on the surgical decision as well as factors influencing this decision. Sixty-seven patients were included (30 males, mean age: 48.3 ± 20.1 years, disease duration: 16.9 ± 15.3 years). Thirty-three (49%) patients underwent DBS. Four (6%) patients were awaiting the procedure while the remaining 30 patients (45%) did not undergo DBS. Reasons for DBS decline were patient refusal (17, 53%), functional dystonia (6, 20%), and successful use of AbobotulinumtoxinA (3, 10%) in patients who had failed other BoNTs. Our study highlights the importance of structured patient education to increase acceptance of DBS, as well as careful patient evaluation, particularly with respect to functional dystonia. Finally, changing BoNT formulation might be beneficial in some patients.

Real-World Dosing of OnabotulinumtoxinA and IncobotulinumtoxinA for Cervical Dystonia and Blepharospasm: Results from TRUDOSE and TRUDOSE II

The real-world use of onabotulinumtoxinA and incobotulinumtoxinA for cervical dystonia and blepharospasm treatment was assessed in two separate retrospective studies using identical protocols (TRUDOSE and TRUDOSE II). The studies were conducted in Mexico, Norway, and United Kingdom and designed to evaluate dose utilization of the two botulinum toxins in clinical practice. Eighty-three patients treated with both onabotulinumtoxinA and incobotulinumtoxinA for ≥2 years for each botulinum toxin were included, (52, cervical dystonia; 31, blepharospasm). All patients switched from onabotulinumtoxinA to incobotulinumtoxinA for administrative/financial reasons. A range of dose ratios (incobotulinumtoxinA to onabotulinumtoxinA) was reported; with the majority of dose ratios being >1. The mean dose ratio was >1 regardless of the study site or underlying clinical condition. The inter-injection interval was significantly longer for onabotulinumtoxinA versus incobotulinumtoxinA when assessed for all patients (15.5 vs. 14.3 weeks; p = 0.006), resulting in fewer onabotulinumtoxinA treatments over the study time period. Consistent with product labeling, no single fixed-dose ratio exists between incobotulinumtoxinA and onabotulinumtoxinA. The dosage of each should be individualized based on patient needs and used as per product labeling. These real-world utilization data may have pharmacoeconomic implications.

Botulinum Toxin in Movement Disorders: An Update

Since its initial approval in 1989 by the US Food and Drug Administration for the treatment of blepharospasm and other facial spasms, botulinum toxin (BoNT) has evolved into a therapeutic modality for a variety of neurological and non-neurological disorders. With respect to neurologic movement disorders, BoNT has been reported to be effective for the treatment of dystonia, bruxism, tremors, tics, myoclonus, restless legs syndrome, tardive dyskinesia, and a variety of symptoms associated with Parkinson's disease. More recently, research with BoNT has expanded beyond its use as a powerful muscle relaxant and a peripherally active drug to its potential central nervous system applications in the treatment of neurodegenerative disorders. Although BoNT is the most potent biologic toxin, when it is administered by knowledgeable and experienced clinicians, it is one of the safest therapeutic agents in clinical use. The primary aim of this article is to provide an update on recent advances in BoNT research with a focus on novel applications in the treatment of movement disorders. This comprehensive review of the literature provides a critical review of evidence-based clinical trials and highlights recent innovative pilot studies.

Pain incidence in cervical dystonia is determined by the disease phenotype

BACKGROUND

Cervical dystonia (CD) is a movement disorder caused by prolonged contractions of the head and neck muscles resulting in abnormal postures and repetitive movements. Depending on the direction of the head and neck deviation, CD phenotypes are divided into torti-, latero-, antero-, and retro- impairments assessed in commonly used TWSTRS classification, or -caput and -collis according to the novel Col-Cap concept. Cervical pain, which pathophysiology has not been fully elucidated, affects more than 60% of CD patients. To date, none of the studies have investigated the risk of pain associated with the particular disease phenotype.

METHODS

In this observational study data collection was based on the survey completion by the participants, analysis of the medical records, and physical examination with the use of proper scales (TWSTRS, Col-Cap, Tsui). Extended pain profile questionnaire included detailed questions about pain localization, character, and intensity.

RESULTS

We examined 60 patients suffered from CD; 66,7% of them reported cervical pain. Latero- as the only TWSTRS phenotype was associated with increased risk of pain occurrence (OR = 3,95; p < 0,05). Interestingly, each of two Col-Cap phenotypes correlated with cervical pain: -caput positively (OR = 3,78; p < 0,05) and -collis negatively (OR = 0,29; p < 0,05).

CONCLUSIONS

The risk of dystonic pain was highly differentiated within the particular CD phenotypes. The enhanced risk of cervical pain was observed in latero- (TWSTRS) and -caput (Col-Cap) phenotypes; conversely, -collis type (Col-Cap) was characterized by the lowest risk of cervical pain.

Use of AbobotulinumtoxinA in Adults with Cervical Dystonia: A Systematic Literature Review

Cervical dystonia (CD) is a neurological movement disorder characterized by sustained involuntary muscle contractions. First-line therapy for CD is intramuscular injections of botulinum neurotoxin (e.g., abobotulinumtoxinA) into the affected muscles. The objective of this systematic literature review is to assess the clinical evidence regarding the effects of abobotulinumtoxinA for treatment of CD in studies of safety, efficacy, patient-reported outcomes, and economic outcomes. Using comprehensive electronic medical literature databases, a search strategy was developed using a combination of Medical Subject Heading terms and keywords. Results were reviewed by two independent reviewers who rated the level of evidence. The search yielded 263 publications, of which 232 were excluded for being duplicate publications, not meeting the selection criteria, or failing to meet predefined eligibility criteria, leaving a total of 31 articles. Clinical efficacy, patient-reported outcomes, and safety data were in 6 placebo-controlled trials (8 articles), 6 active-controlled trials, and 16 observational studies (17 articles). Data on health economic outcomes were provided in one of the clinical trials, in two of the observational studies, and in one specific cost-analysis publication. This review demonstrated that the routine use of abobotulinumtoxinA in CD is well-established, effective, and generally well-tolerated, with a relatively low cost of treatment.

Economic evaluation of AbobotulinumtoxinA vs OnabotulinumtoxinA in real-life clinical management of cervical dystonia

Background

Botulinum neurotoxins type A (BoNT-As) are commonly used treatments for cervical dystonia (CD). Clinical trials have demonstrated the benefits of them in these patients, but data from real-life clinical practice as well as comparative data on the cost and outcome of different BoNT-A formulations are limited. The aim of this study was to compare abobotulinumtoxinA (aboBoNT-A) and onabotulinumtoxinA (onaBoNT-A) on their clinical outcomes and drug costs in real-life clinical practice.

Methods

This analysis included 356 adult patients with idiopathic CD treated with aboBoNT-A (n = 253) or onaBoNT-A (n = 103) from 38 centres across Europe and Australia (NCT00833196). The clinical outcome measures were treatment responses, changes in TWSTRS scores and changes in health utility scores from baseline to study visit 2 and 3. Health utility score was mapped from the TWSTRS total scale, using a previous publication. Costs included drug cost for France.

Results

The aboBoNT-A treated group had 2.06 (95% CI: 1.15 to 3.69) times higher odds of achieving treatment response than the onaBoNT-A treated group. The adjusted mean change in TWSTRS total score from baseline to visit 3 were - 6.42 (95% CI: - 7.52 to - 5.33) for aboBoNT-A and - 3.94 (95% CI: - 5.68 to - 2.2) for onaBoNT-A, with a difference of - 2.48 (95% CI: - 4.57 to - 0.39). The corresponding difference in the adjusted mean change for health utility score was 0.008 (95% CI: 0.001 to 0.014). Mean treatment costs for aboBoNT-A and onaBoNT-A were 314.1 (95% CI: 299.1 to 329.0) and 346.6 (95% CI: 322.9 to 370.4) Euros, respectively.

Conclusions

This comparative analysis indicated that treatment with aboBoNT-A may be less costly and lead to improved clinical outcomes when compared with onaBoNT-A, from a French healthcare system perspective. Additional comparative clinical data from larger patient cohorts, as well as more information about cost consequences of an improvement in clinical outcome would be of value to further confirm the findings.

Six-Month Comparative Analysis Monitoring the Progression of the Largest Diameter of the Sweating Inhibition Halo of Different Botulinum Toxins Type-A

BACKGROUND

Excessive sweating is a clinical condition that can be improved with type-A botulinum toxin (BTX-A).

OBJECTIVES

To evaluate and compare the largest diameter of sweating inhibition halo (SIH) of 5 different commercially available BTX-A, in five different doses, in a 6-month-long clinical evaluation.

METHODS

Twenty-five adult female volunteers were injected in the dorsal trunk area with both 100 units (100UI) and 500 units (500UI) BTX-A products, reconstituted in a ratio of 1:2.5 IU, respectively. Products were applied in five different concentrations (1:2.5U, 2:5U, 3:7.5U, 4:10U, and 5:12.5U). After 30, 60, 90, 120, 150, and 180 days, a starch-iodine test was performed to obtain the largest diameter of each SIH.

RESULTS

The higher the number of units used, the larger the SIH p < 0.05 for all BTX-A. However, Botox®, Botulift®, Dysport®, and Prosigne® have pretty likewise SIH along the study, with some few differences for some doses and months between one and another. However, Xeomin® is the BTX-A with the smallest SIH, in comparison with all others, in any dose and period.

CONCLUSIONS

Differences were observed among all brands of BTX-As, based on dose and time after injection. Xeomin® provides the smallest SIH in comparison with others BTX-A.

LEVEL OF EVIDENCE: 2

The Use of Botulinum Toxin in Strabismus Treatment

There is a long and extensive experience with the use of Botulinum Toxin type A (BoNT-A) injection in the treatment of different types of strabismus and oculomotor palsies. The frequency of its use varies depending on the country and institution. It is a short procedure, may reduce general anesthesia exposure, causes minimal scarring compared to surgery, and can be proposed as an early treatment in unstable strabismus. Over many years, the experience of using BoNT-A indications has been refined and new applications have been reported. The use of BoNT-A in the postoperative period, after strabismus surgery or during surgery, can also be beneficial.

Pain in cervical dystonia and the antinociceptive effects of botulinum toxin: what is currently known?

Pain is the most common and disabling non-motor symptom in cervical dystonia (CD). Up to 88.9% of patients report pain at some point in the course of the disease. It is still a matter of debate whether CD-related pain originates only from prolonged muscle contraction. Recent data suggest that the alterations of transmission and processing of nociceptive stimuli play a crucial role in pain development. Botulinum toxin (BT) is the first-line therapy for CD. Despite fully elucidated muscle relaxant action, the antinociceptive effect of BT remains unclear and probably exceeds a simple decompression of the nerve fibers due to the reduction in muscle tone. The proposed mechanisms of the antinociceptive action of BT include inhibition of pain mediator release, inhibition of membrane sodium channels, retrograde axonal transport and impact on the other pain pathways. This article summarizes the current knowledge about the antinociceptive properties of BT and the clinical analgesic efficacy in the treatment of CD patients.

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.

Spectrum of practice in the routine management of cervical dystonia with abobotulinumtoxinA: findings from three prospective open-label observational studies

Background

Cervical dystonia is a heterogeneous disorder with several possible presentations, for which first-line therapy is often botulinum toxin (BoNT). In routine clinical practice the success of each BoNT injection is dependent on several variables, including individual presentation and injection technique. Large multicenter, observational studies provide important information on individualized administration strategies that cannot be otherwise ascertained from controlled clinical trials. In this meta-analysis of patient level data, we aimed to evaluate the clinical characteristics of patients with cervical dystonia undergoing routine treatment with botulinum toxin, specifically abobotulinumtoxinA. We also aimed to characterize current abobotulinumtoxinA injection techniques and parameters and to explore international differences in patient presentation and treatment.

Methods

This was a meta-analysis of baseline data from three prospective, international, multicenter, observational studies (NCT01314365, NCT00833196 and NCT01753349) of botulinum toxin treatment for the routine management of adult cervical dystonia.

Results

Data presented illustrate the significant heterogeneity of CD presentation in routine practice. Most subjects presented with a complex pattern of dystonic movements and the majority had additional components of shoulder elevation, tremor and/or jerk. Dosing was generally in accordance with that recommended in the abobotulinumtoxinA prescribing information, although the range of dosing also indicates that injections are tailored to individual presentation. Sub-group analyses at the country level revealed distinct differences in injection practice.

Conclusions

This meta-analysis is based on the largest dataset of subjects with cervical dystonia studied to date. The heterogeneity revealed in our baseline findings support the need to develop consistent, practical and comprehensive best practice guidelines.

Botulinum neurotoxin formulations: overcoming the confusion

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

Pilot Single-Blind Trial of AbobotulinumtoxinA in Oromandibular Dystonia

Oromandibular dystonia (OMD) causes involuntary movements of masticatory and lingual muscles impairing eating, speaking, and swallowing. Treatment options are limited. The objective of this study was to determine the safety and efficacy of abobotulinumtoxinA (aboBoNTA) in OMD. A dose-finding study (phase 1) followed by a single session, prospective, single-blind trial (phase 2) was carried out. OMD subjects were evaluated at baseline, 6 and 12 weeks. Muscles injected were tailored to individual symptoms using EMG guidance, but the aboBoNTA dose for each muscle was pre-specified based on phase 1 results. Evaluations were Global Dystonia Rating Scale (GDS), Unified Dystonia Rating Scale (UDRS), Clinical Global Impression (CGI) improvement and severity, and quality of life (OMDQ-25). Adverse events were monitored. The lowest dosage in phase 1 resulted in adverse effects in two of three patients and thus was used in phase 2. In phase 2, adverse effects were observed in 50% of subjects including dysphagia, voice change, and soft palate weakness. Most were mild. Significant improvement was seen in quality of life (OMDQ-25), speech (BFMq21), and change in GDS, UDRS, CGI severity assessed by the unblinded investigator, but not in blinded video ratings. We conclude that aboBoNTA therapy in this study was associated with improved quality of life and was generally well tolerated in OMD, but occurrence of dysphagia dictated the importance of using low genioglossus dosing. Face to face assessment appears to be more sensitive than video assessment for change in OMD severity. Consideration of the disability in OMD places constraints on traditional placebo-control trial design. Development of novel trial designs is warranted.

Recent developments in clinical trials of botulinum neurotoxins

Botulinum neurotoxins (BoNTs) are increasingly used in clinical practice for several indications. Following the pioneering years of discoveries, the recent years have witnessed an increase of new indications and new toxin brands. We review here the clinical trials on BoNTs performed since 2014 and put them into perspective. We also review the ongoing trials listed by the National Institutes of Health registry (Clinicaltrials.gov). The following indications are reviewed here: blepharospasm, cervical dystonia, spasticity, cerebral palsy, urinary incontinence, headache, topical formulations, postoperative cardiac arrhythmia, keloids and scars. For each of these indications the latest trials are reviewed and commented.

Clinical Practice: Evidence-Based Recommendations for the Treatment of Cervical Dystonia with Botulinum Toxin

Cervical dystonia (CD) is the most frequent form of focal dystonia. Symptoms often result in pain and functional disability. Local injections of botulinum neurotoxin are currently the treatment of choice for CD. Although this treatment has proven effective and is widely applied worldwide, many issues still remain open in the clinical practice. We performed a systematic review of the literature on botulinum toxin treatment for CD based on a question-oriented approach, with the aim to provide practical recommendations for the treating clinicians. Key questions from the clinical practice were explored. Results suggest that while the beneficial effect of botulinum toxin treatment on different aspects of CD is well established, robust evidence is still missing concerning some practical aspects, such as dose equivalence between different formulations, optimal treatment intervals, treatment approaches, and the use of supportive techniques including electromyography or ultrasounds. Established strategies to prevent or manage common side effects (including excessive muscle weakness, pain at injection site, dysphagia) and potential contraindications to this treatment (pregnancy and lactation, use of anticoagulants, neurological comorbidities) should also be further explored.

Unmet Needs in the Management of Cervical Dystonia

Cervical dystonia (CD) is a movement disorder which affects daily living of many patients. In clinical practice, several unmet treatment needs remain open. This article focuses on the four main aspects of treatment. We describe existing and emerging treatment approaches for CD, including botulinum toxin injections, surgical therapy, management of non-motor symptoms, and rehabilitation strategies. The unsolved issues regarding each of these treatments are identified and discussed, and possible future approaches and research lines are proposed.

A Retrospective, Single-Center Comparative Cost Analysis of OnabotulinumtoxinA and AbobotulinumtoxinA for Cervical Dystonia Treatment

BACKGROUND

Chemodenervation with botulinum neurotoxin (BoNT) is recommended as first-line treatment for the management of cervical dystonia. The choice of BoNT for treatment is subject to the consideration of several factors, including cost.

OBJECTIVE

To compare the costs incurred by patients and payers for onabotulinumtoxinA (ONA) or abobotulinumtoxinA (ABO) for the treatment of cervical dystonia.

METHODS

We conducted a retrospective, noninterventional closed cohort study of cervical dystonia patients within a single U.S. private neurological practice. Patient and payer incurred costs from medical billing records for patients satisfying inclusion and exclusion criteria treated from November 1, 2009, through January 1, 2013, were de-identified and included in the analysis. Forty-seven patients initially treated with at least 3 consecutive cycles of ONA, followed by at least 3 consecutive cycles of ABO were included, representing 282 injection cycles available for analysis. Patients were required to have had a positive response to treatment with both agents and no concomitant treatment with BoNT for any other condition during the analysis period. The analysis compared the primary endpoint of median overall payer and patient incurred costs reimbursed to the clinic under each treatment regimen. For the purposes of this cost analysis, comparable clinical outcomes on both therapies was assumed.  

RESULTS

Switching from ONA to ABO resulted in an overall incurred reimbursement cost savings for payers and patients. Median costs per injection cycle for ONA were $1,925 ($0-$2,814) compared with $1,214 ($229-$2,899; P  less than  0.0001) for ABO, representing an approximate 37% reduction in incurred reimbursement costs inclusive of toxin and procedure. Overall toxin reimbursement costs, patient out-of-pocket toxin costs, and the cost of unavoidable waste were also lower when patients were treated with ABO. 

CONCLUSIONS

For patients treated for cervical dystonia, switching from ONA to ABO resulted in payer and patient reimbursement cost reductions in a single U.S. private practice with outcomes assumed to be similar.

Practice guideline update summary: Botulinum neurotoxin for the treatment of blepharospasm, cervical dystonia, adult spasticity, and headache: Report of the Guideline Development Subcommittee of the American Academy of Neurology

OBJECTIVE

To update the 2008 American Academy of Neurology (AAN) guidelines regarding botulinum neurotoxin for blepharospasm, cervical dystonia (CD), headache, and adult spasticity.

METHODS

We searched the literature for relevant articles and classified them using 2004 AAN criteria.

RESULTS AND RECOMMENDATIONS

Blepharospasm: OnabotulinumtoxinA (onaBoNT-A) and incobotulinumtoxinA (incoBoNT-A) are probably effective and should be considered (Level B). AbobotulinumtoxinA (aboBoNT-A) is possibly effective and may be considered (Level C). CD: AboBoNT-A and rimabotulinumtoxinB (rimaBoNT-B) are established as effective and should be offered (Level A), and onaBoNT-A and incoBoNT-A are probably effective and should be considered (Level B). Adult spasticity: AboBoNT-A, incoBoNT-A, and onaBoNT-A are established as effective and should be offered (Level A), and rimaBoNT-B is probably effective and should be considered (Level B), for upper limb spasticity. AboBoNT-A and onaBoNT-A are established as effective and should be offered (Level A) for lower-limb spasticity. Headache: OnaBoNT-A is established as effective and should be offered to increase headache-free days (Level A) and is probably effective and should be considered to improve health-related quality of life (Level B) in chronic migraine. OnaBoNT-A is established as ineffective and should not be offered for episodic migraine (Level A) and is probably ineffective for chronic tension-type headaches (Level B).

Botulinum toxin injection for restrictive myopathy of thyroid-associated orbitopathy: success rate and predictive factors

PURPOSE

To evaluate the rate of and predictive factors for successful treatment of restrictive myopathy in thyroid-associated orbitopathy (TAO) using botulinum toxin injection.

METHODS

Twenty patients with restrictive myopathy of TAO were enrolled in the study. Abnormal thyroid function test results were not a prerequisite for inclusion. In each extraocular muscle 25 units of botulinum toxinA were injected. The success rate, calculated at 2 years or last follow-up before surgery, was defined as proportion of the cases with esotropia of <10(Δ), vertical deviation of <5(Δ), and no diplopia in primary position and downgaze for at least 1 year. Both univariate analysis and multivariate logistic regressions were performed to identify the factors associated with success.

RESULTS

The procedure was successful in 11 cases (55%): in 8 patients with predominantly esotropia, 1 patient with predominantly hypotropia, and 2 patients of mixed type. Four factors were significantly associated with the success: type of deviation (P = 0.007), lower amounts of hypotropia (P = 0.001) and esotropia (P = 0.05), and lower degree of extorsion (P = 0.01). In the multivariate logistic regression, only lower amount of hypotropia was significantly associated with the success (P = 0.09, OR = 1.36).

CONCLUSIONS

Botulinum toxin injection can be an effective alternative for the treatment of the restrictive myopathy in TAO. The best candidates for injection of the toxin are patients with esotropia, smaller angle of horizontal and vertical deviations, and lower degree of extorsion.

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.

OnabotulinumtoxinA and AbobotulinumtoxinA Dose Conversion: a Systematic Literature Review

Objective

This systematic review was performed to elucidate dosing practices, dosing conversions, and related outcomes from randomized, controlled trials that directly compared onabotulinumtoxinA (ONA) and abobotulinumtoxinA (ABO) at various dose conversion ratios for therapeutic use in movement disorders.

Methods

A systematic review of three medical literature databases (PubMed, the Cochrane Library, and EMBASE) was performed to identify relevant comparative clinical studies, systematic reviews, and meta‐analyses published in the English language between January 1991 and January 2015. Studies that met predefined inclusion criteria were selected for formal data extraction and quality assessment.

Results

A total of 182 manuscripts were identified, of which four were included for analysis. Targeted clinical applications included neurological disorders. The studies compared ONA to ABO dose conversion ratios of 1:2.5 (n = 1), 1:3 (n = 2), and 1:4 (n = 2). One study compared both 1:3 and 1:4 ratios. An ONA:ABO conversion factor of 1:2.5 was associated with similar efficacy and side effects. An ONA:ABO ratio of 1:3 provided similar or higher efficacy, but an increased rate of adverse effects, and an ONA:ABO ratio of 1:4 was associated with higher efficacy, but with an excessive rate of intolerable side effects.

Conclusion

A dose conversion ratio of ONA to ABO between 1:2.5 and 1:3.0 provides comparable safety and efficacy for therapeutic movement disorders chemodenervation procedures.