Efficacy and safety of higher doses of botulinum toxin type A NT 201 free from complexing proteins in the upper and lower limb spasticity after stroke

The Role of Botulinum Toxin Type-A in Spasticity: Research Trends from a Bibliometric Analysis

Botulinum toxin type-A (BoNT-A) has emerged as a key therapeutic agent for the management of spasticity. This paper presents a comprehensive bibliometric and visual analysis of research concerning BoNT-A treatment of spasticity to elucidate current trends and future directions in this research area. A search was conducted in the Web of Science database for articles focused on the use of BoNT-A in spasticity published between 2000 and 2022. We extracted various metrics, including counts of publications and contributions from different countries, institutions, authors, and journals. Analytical methods in CiteSpace were employed for the examination of co-citations, collaborations, and the co-occurrence of keywords. Our search yielded 1489 publications. Analysis revealed a consistent annual increase in research output. The United States, United Kingdom, and Italy were the leading contributors. The top institution in this research was Assistance Publique Hopitaux, Paris. The journal containing the highest number of relevant publications was Toxins. Key frequently occurring keywords were 'stroke', 'cerebral palsy', 'adult spasticity', and 'upper extremity'. This study identified 12 clusters of keywords and 15 clusters of co-cited references, indicating the main focus areas and emerging themes in this field. This study comprehensively analyzed and summarized trends in BoNT-A research in the field of spasticity over the past 22 years.

High-definition transcranial direct current stimulation for upper extremity rehabilitation in moderate-to-severe ischemic stroke: a pilot study

Introduction

Previous studies found that post-stroke motor impairments are associated with damage to the lesioned corticospinal tract (CST) and hyperexcitability of the contralesional cortico-reticulospinal tract (CRST). This proof-of-concept study aims to develop a non-invasive brain stimulation protocol that facilitates the lesioned CST and inhibits the contralesional CRST to improve upper extremity rehabilitation in individuals with moderate-to-severe motor impairments post-stroke.

Methods

Fourteen individuals (minimum 3 months post ischemic stroke) consented. Physician decision of the participants baseline assessment qualified eight to continue in a randomized, double-blind cross-over pilot trial (ClinicalTrials.gov Identifier: NCT05174949) with: (1) anodal high-definition transcranial direct stimulation (HD-tDCS) over the ipsilesional primary motor cortex (M1), (2) cathodal HD-tDCS over contralesional dorsal premotor cortex (PMd), (3) sham stimulation, with a two-week washout period in-between. Subject-specific MR images and computer simulation were used to guide HD-tDCS and verified by Transcranial Magnetic Stimulation (TMS) induced Motor Evoked Potential (MEP). The motor behavior outcome was evaluated by an Fugl-Meyer Upper Extremity score (primary outcome measure) and the excitability of the ipslesoinal CST and contralesional CRST was determined by the change of MEP latencies and amplitude (secondary outcome measures).

Results

The baseline ipsilesional M1 MEP latency and amplitude were correlated with FM-UE. FM-UE scores were improved post HD-tDCS, in comparison to sham stimulation. Both anodal and cathodal HD-tDCS reduced the latency of the ipsilesional M1 MEP. The contralesional PMd MEP disappeared/delayed after HD-tDCS.

Discussion

These results suggest that HD-tDCS could improve the function of the lesioned corticospinal tract and reduce the excitability of the contralesional cortico-reticulospinal tract, thus, improving motor function of the upper extremity in more severely impaired individuals.

Botulinum Toxin-A High-Dosage Effect on Functional Outcome and Spasticity-Related Pain in Subjects with Stroke

Stroke patients can develop spasticity and spasticity-related pain (SRP). These disorders are frequent and can contribute to functional limitations and disabling conditions. Many reports have suggested that higher doses than initially recommended of BTX-A can be used effectively and safely, especially in the case of severe spasticity; however, whether the treatment produces any benefit on the functional outcome and SRP is unclear. Studies published between January 1989 and December 2022 were retrieved from MEDLINE/PubMed, Embase, and Cochrane Central Register. Only obabotulinumtoxinA (obaBTX-A), onabotulinumtoxinA, (onaBTX-A), and incobotulinumtoxinA (incoBTX-A) were considered. The term "high dosage" indicates ≥600 U. Nine studies met the inclusion criteria. Globally, 460 subjects were treated with BTX-A high dose, and 301 suffered from stroke. Studies had variable method designs, sample sizes, and aims. Only five (55.5%) reported data about the functional outcome after BTX-A injection. Functional measures were also variable, and the improvement was observed predominantly in the disability assessment scale (DAS). SRP pain was quantified by visual analog scale (VAS) and only three studies reported the BTX-A effect. There is no scientific evidence that this therapeutic strategy unequivocally improves the functionality of the limbs. Although no clear-cut evidence emerges, certain patients with spasticity might obtain goal-oriented improvement from high-dose BTX-A. Likewise, data are insufficient to recommend high BTX dosage in SRP.

High Doses of Botulinum Toxin Type A for the Treatment of Post-Stroke Spasticity: Rationale for a Real Benefit for the Patients

In the past few years, there was a great interest in the use of higher doses of botulinum toxin type A, especially in case of upper and lower limb severe spasticity. To date, only one prospective, non-randomized, single-arm, multicenter, open-label, dose-titration study with the employment of incobotulinum toxin up to 800 U has been published, and the authors investigated safety and tolerability. Other researches showed efficacy in spasticity reduction, but there is a lack of evidence about the reasons to use high doses of botulinum toxin. This short communication highlights the benefits of higher doses for subjects with upper and lower limb spasticity.

Acupuncture treatment for spasticity after brain injury

Spasticity after brain injury is a neurological sequela caused by damage to upper motor neurons. The primary symptoms are involuntary muscle activity, decreased muscle strength, and joint contracture. Acupuncture as a therapeutic method to regulate central nervous system function has been studied widely in recent years. Many clinical experiments have proved that acupuncture has positive effects on spasticity after brain injury. In this review, we discuss recent research of acupuncture treatment and the need for large randomized controlled trials.

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.

Quality of life in subjects with upper- and lower-limb spasticity treated with incobotulinumtoxinA

Background

We evaluated quality of life among subjects with upper- and lower-limb spasticity who received escalating doses of incobotulinumtoxinA (total body doses up to 800 U) in the prospective, single-arm, dose-titration TOWER study.

Methods

In this exploratory trial, subjects (N = 155; 18–80 years of age) with upper- and lower-limb spasticity due to cerebral causes who were deemed to require total body doses of up to 800 U incobotulinumtoxinA received three consecutive injection cycles of incobotulinumtoxinA (400, 600, and up to 800 U), each with 12 to 16 weeks’ follow-up. QoL was assessed using the EuroQol 5-dimensions questionnaire, three-level (EQ-5D), before and 4 weeks post-injection in each injection cycle and at the end of injection cycle 3.

Results

The mean EQ-5D visual analog scale scores of 155 participants continuously improved from study baseline to 4 weeks post-injection in all injection cycles (mean [standard deviation] change 6.7 [14.1], 9.6 [16.3], and 8.6 [17.0] for injection cycles 1, 2, and 3, respectively; p < 0.0001 for all, paired sample t-test). In general, among those with a change in the EQ-5D rating of their condition, the proportion of subjects with ‘improvement’ was greater than that with ‘worsening’ for individual EQ-5D dimensions across all injection cycles. At the end of injection cycle 3, the proportion of subjects rating their condition as ‘normal’ increased from study baseline for all dimensions, and there was a ≥ 46% reduction in the proportion of subjects with a rating of ‘severe impairment’.

Conclusion

These preliminary results suggest that escalating incobotulinumtoxinA doses up to 800 U are associated with improvement in quality of life ratings in subjects with multifocal upper- and lower-limb spasticity, and form a basis for future comparator studies.

Trial registration

ClinicalTrials.gov, NCT01603459. Date of registration: May 22, 2012.

Botulinum Toxin Type A for the Treatment of Lower Limb Spasticity after Stroke

Post-stroke lower limb spasticity impairs balance and gait leading to reduced walking speed, often increasing wheelchair use and caregiver burden. Several studies have shown that appropriate treatments for lower limb spasticity after stroke include injections of botulinum toxin type A (BoNT-A), phenol or alcohol, surgical correction and a rehabilitation program. In the present article, we review the safety and effectiveness of BoNT-A for the treatment of lower limb spasticity after stroke, with a focus on higher doses of BoNT-A. The cumulative body of evidence coming from the randomized clinical trials and open-label studies selected in the article suggest BoNT-A to be safe and efficacious in reducing lower limb spasticity after stroke. Studies of high doses of BoNT-A also showed a greater reduction of severe post-stroke spasticity. In stroke survivors with spasticity of the ankle plantar-flexor muscles, a combined approach between surgery and BoNT-A can be indicated. However, controversy remains about improvement in motor function relative to post-stroke spasticity reduction after BoNT-A treatment.

Combined Effects of Isokinetic Training and Botulinum Toxin Type A on Spastic Equinus Foot in Patients with Chronic Stroke: A Pilot, Single-blind, Randomized Controlled Trial

Botulinum toxin A (BoNT-A) has been shown effective for poststroke lower limb spasticity. Following injections, a wide range of multidisciplinary approach has been previously provided. The purpose of this pilot, single-blind, randomized controlled trial was to determine whether BoNT-A combined with a regime of a four-week ankle isokinetic treatment has a positive effect on function and spasticity, compared with BoNT-A alone. Secondly, the validity of the use of an isokinetic dynamometer to measure the stretch reflex at the ankle joint and residual strength has been investigated. Twenty-five chronic stroke patients were randomized to receive combined treatment (n = 12; experimental group) or BoNT-A alone (n = 13; control group). Outcome measures were based on the International Classification of Functioning, Disability and Health. An isokinetic dynamometer was also used for stretch reflex and strength assessment. Patients were evaluated at baseline (t0), after five (t1) and eight weeks after the injection (t2). The experimental group reported significantly greater improvements on lower limb spasticity, especially after eight weeks from baseline. Gait speed (10-m walk test) and walking capacity (6-min walking test) revealed statistically significantly better improvement in the experimental than in control group. Peak resistive ankle torque during growing angular velocities showed a significant reduction at the higher velocities after BoNT-A injections in the experimental group. Peak dorsiflexor torque was significantly increased in the experimental group and peak plantarflexor torque was significantly decreased in control group. Alternative rehabilitation strategies that combine BoNT-A and an intense ankle isokinetic treatment are effective in reducing tone and improving residual strength and motor function in patients with chronic hemiparesis.

Efficacy and Safety of Botulinum Toxin Type A for Limb Spasticity after Stroke: A Meta-Analysis of Randomized Controlled Trials

Background

Inconsistent data have been reported for the effectiveness of intramuscular botulinum toxin type A (BTXA) in patients with limb spasticity after stroke. This meta-analysis of available randomized controlled trials (RCTs) aimed to determine the efficacy and safety of BTXA in adult patients with upper and lower limb spasticity after stroke.

Methods

An electronic search was performed to select eligible RCTs in PubMed, Embase, and the Cochrane library through December 2018. Summary standard mean differences (SMDs) and relative risk (RR) values with corresponding 95% confidence intervals (CIs) were employed to assess effectiveness and safety outcomes, respectively.

Results

Twenty-seven RCTs involving a total of 2,793 patients met the inclusion criteria, including 16 and 9 trials assessing upper and lower limb spasticity cases, respectively. For upper limb spasticity, BTXA therapy significantly improved the levels of muscle tone (SMD=-0.76; 95% CI -0.97 to -0.55; P<0.001), physician global assessment (SMD=0.51; 95% CI 0.35-0.67; P<0.001), and disability assessment scale (SMD=-0.30; 95% CI -0.40 to -0.20; P<0.001), with no significant effects on active upper limb function (SMD=0.49; 95% CI -0.08 to 1.07; P=0.093) and adverse events (RR=1.18; 95% CI 0.72-1.93; P=0.509). For lower limb spasticity, BTXA therapy was associated with higher Fugl-Meyer score (SMD=5.09; 95%CI 2.16-8.01; P=0.001), but had no significant effects on muscle tone (SMD=-0.12; 95% CI -0.83 to 0.59; P=0.736), gait speed (SMD=0.06; 95% CI -0.02 to 0.15; P=0.116), and adverse events (RR=1.01; 95% CI 0.71-1.45; P=0.949).

Conclusions

BTXA improves muscle tone, physician global assessment, and disability assessment scale in upper limb spasticity and increases the Fugl-Meyer score in lower limb spasticity.

Benefits and Risks of Non-Approved Injection Regimens for Botulinum Toxins in Spasticity

Spasticity with muscle paresis and loss of dexterity is a common feature of upper motor neuron syndrome due to injuries or the pyramidal tract in several neurological conditions. Botulinum toxin type A has been considered the gold standard treatment for spasticity and movement disorders, with efficacy, reversibility, and low prevalence of complications. During the last 30 years, thousands of studies of its use have been performed, but few guidelines are available. Therefore, there is great variability in both the doses and intervals of administration and the approaches taken by clinicians with considerable experience in spasticity and movement disorder treatment. In the present review article, we provide a short overview of the benefits and risks of non-approved injection regimens and doses for botulinum toxins, focusing on the treatment of post-stroke spasticity, where there is great interest in the potential for increasing the number of treatment/years and the dose of botulinum toxin treatment for subjects with upper and lower limb spasticity. However, many doubts exist regarding antibody development and possible adverse effects.

Towards flexible and tailored botulinum neurotoxin dosing regimens for focal dystonia and spasticity - Insights from recent studies

Botulinum neurotoxin (BoNT) is an effective, well-tolerated, and well-established option for the treatment of dystonic and spastic movement disorders. However, a single approach does not suit all patients, even within one disease indication. The degree of flexibility in treatment protocols is determined by individual product licenses, which often lag behind real-world clinical experience. A number of patient/practitioner surveys conducted recently have highlighted a desire for greater flexibility than that currently approved, both in BoNT doses and in the intervals between consecutive doses. New evidence arising from research conducted during the last few years has opened new avenues for tailoring BoNT treatment to patients' needs. Data suggest that escalating incobotulinumtoxinA doses enables treatment of a greater number of spasticity patterns than current dose limitations allow, without compromising safety or tolerability. Similarly, in patients with cervical dystonia (CD), repeated injections of incobotulinumtoxinA at intervals as early as 6 weeks after a previous treatment, based on individual patient need, were effective and well tolerated. Here, the BoNT doses and dosing intervals currently indicated in the USA and European Union are reviewed, together with the use of BoNT for the treatment of spasticity, CD, and blepharospasm. Opportunities for tailored BoNT therapy are also discussed.

Heart Rate Variability modifications induced by high doses of incobotulinumtoxinA and onabotulinumtoxinA in hemiplegic chronic stroke patients: A single blind randomized controlled, crossover pilot study

BACKGROUND

Botulinum toxin type A is a valid and safe treatment for focal spasticity, with documented effects on both sympathetic and parasympathetic systems. Heart rate variability can provide detailed information about the control of the autonomic nervous system on cardiovascular activities. Previous studies in literature showed no significant changes in Heart Rate Variability with doses >600 U of incobotulinumtoxinA in chronic post stroke spastic patients; however, at present time, these results have not been confirmed with doses >600 U of onabotulinumtoxinA.

AIM

To evaluate changes in Heart Rate Variability induced by high doses (>600 U) of incobotulinumtoxinA or onabotulinumtoxinA in spastic stroke patients over a 1-year period.

DESIGN

single blind randomized controlled crossover study design.

SETTING

Rehabilitation Unit of the University Hospital in Novara.

POPULATION

10 stroke survivors with spastic hemiplegia (Modified Ashworth Scale ≥ 2) were recruited and randomly divided in two groups (A and B).

METHODS

In the first part of the study, patients in Group A were injected with incobotulinumtoxinA while patients in Group B with onabotulinumtoxinA; after 6 months, a crossover intervention was performed. All patients were blinded to Botulinum toxin type A type, and performed an ECG registration in the 24 h before injection (t0) and 10 days after treatment (t1), both in the first and in the second part of the study. Functional status was evaluated with Barthel Index, Motricity Index and Functional Ambulation Category scores.

RESULTS

Heart Rate Variability analysis showed no significant changes after each Botulinum toxin type A injection in both groups at any evaluation time. Moreover, no statistically significant differences were found regarding each variable between the two groups.

CONCLUSIONS

Our data show that high doses (>600 U) of incobotulinumtoxinA and onabotulinumtoxinA do not influence the cardiovascular activity of the autonomic nervous system in chronic hemiplegic spastic stroke survivors.

Safety and efficacy of incobotulinumtoxinA doses up to 800 U in limb spasticity: The TOWER study

Objective:

To evaluate safety (primary objective) and efficacy of increasing doses (400 U up to 800 U) of incobotulinumtoxinA (Xeomin, Merz Pharmaceuticals GmbH) for patients with limb spasticity.

Methods:

In this prospective, single-arm, dose-titration study (NCT01603459), patients (18–80 years) with spasticity due to cerebral causes, who were clinically deemed to require total doses of 800 U incobotulinumtoxinA, received 3 consecutive injection cycles (ICs) with 400 U, 600 U, and 600–800 U incobotulinumtoxinA, respectively, each followed by 12–16 weeks' observation. Outcomes included adverse events (AEs), antibody testing, Resistance to Passive Movement Scale (REPAS; based on the Ashworth Scale), and Goal Attainment Scale.

Results:

In total, 155 patients were enrolled. IncobotulinumtoxinA dose escalation did not lead to an increased incidence of treatment-related AEs (IC1: 4.5%; IC2: 5.3%; IC3: 2.9%). No treatment-related serious AEs occurred. The most frequent AEs overall were falls (7.7%), nasopharyngitis, arthralgia, and diarrhea (6.5% each). Five patients (3.2%) discontinued due to AEs. No patient developed secondary nonresponse due to neutralizing antibodies. Mean (SD) REPAS score improvements from each injection to 4 weeks postinjection increased throughout the study (IC1: −4.6 [3.9]; IC2: −5.9 [4.2]; IC3: −7.1 [4.8]; p < 0.0001 for all). The proportion of patients achieving ≥3 (of 4) treatment goals also increased (IC1: 25.2%; IC2: 50.7%; IC3: 68.6%).

Conclusion:

Escalating incobotulinumtoxinA doses (400 U up to 800 U) did not compromise safety or tolerability, enabled treatment in a greater number of muscles/spasticity patterns, and was associated with increased treatment efficacy, improved muscle tone, and goal attainment.

ClinicalTrials.gov identifier:

NCT01603459.

Classification of evidence:

This study provides Class IV evidence that, for patients with limb spasticity, escalating incobotulinumtoxinA doses (400 U up to 800 U) increases treatment efficacy without compromising safety or tolerability.

Therapeutic efficacy and safety of various botulinum toxin A doses and concentrations in spastic foot after stroke: a randomized controlled trial

No recommended guidelines currently exist for the therapeutic concentration or dose of botulinum toxin type A (BTXA) injected into the muscle to treat limb spasticity. Therefore, in this randomized controlled trial, we explored the safety and efficacy of two concentrations and two doses of BTXA in the treatment of spastic foot after stroke to optimize this treatment in these patients. Eligible patients (n = 104) were randomized into four groups. The triceps surae and tibialis posterior on the affected side were injected with BTXA at one of two doses (200 U or 400 U) and two concentrations (50 U/mL or 100 U/mL). The following assessments were conducted before as well as 4 days and 1, 2, 4, and 12 weeks after treatment: spasticity, assessed using the modified Ashworth scale; basic functional mobility, assessed using a timed up and go test; pace, assessed using a 10-meter timed walking test; and the ability to walk, assessed using Holden's graded scale and a visual analog scale. The reported results are based on the 89 patients that completed the study. We found significant differences for the two doses and concentrations of BTXA to improve the ability of patients to walk independently, with the high-dose/low-concentration combination providing the best effect. Onset and duration of the ameliorating effects of BTXA were 4–7 days and 12 weeks, respectively. Thus, BTXA effectively treated foot spasms after stroke at an optimal dose of 400 U and concentration of 50 U/mL.

Safety profile of incobotulinum toxin A [Xeomin(®)] in gastrocnemious muscles injections in children with cerebral palsy: Randomized double-blind clinical trial

BACKGROUND

The only two preparations of botulinum toxin A for which there are published evidences of efficacy in children with cerebral palsy are onabotulinum toxin A (Botox(®)) and abobotulinum toxin A (Dyport(®)); these toxins should be considered generally safe and appropriate in the treatment for localized upper and lower limb spasticity.

AIMS

To establish the safety profile of incobotulinum toxin A (Xeomin(®)) in children with cerebral palsy and muscle spasticity.

METHODS

Randomized double-blind controlled trial that involved the recruitment of children of both sexes with spastic hemiplegia or diplegia in cerebral palsy, aged between 3 and 18 years. Children were randomized to either the study group (SG, incobotulinum toxin A) or the control group (CG, onabotulinum toxin A) both to be injected with 5units/kg on gastrocnemius (medialis and lateralis) muscles. The occurrence of adverse events at baseline, after 48 h, 10 days and 3 months was recorded by the caregivers in a checklist that listed both common and uncommon side effects.

RESULTS

35 patients were treated (CG = 18; SG = 17); the 2 groups were well balanced regarding demographics and anthropometry characteristics. At least 1 adverse event occurred in 49% of patients within first 2 days, 46% between 2 and 10 days, and 12% between 10 and 90 days. All the reported events were minor; no serious adverse event was recorded. Fatigue was the most frequent complaint. There was no significant difference in frequency and type of events between the 2 groups.

CONCLUSION

Incobotulinum toxin A and onabotulinum toxin A share similar profile of safety in the treatment of lower limb spasticity in CP children.

Guidelines for Adult Stroke Rehabilitation and Recovery: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association

PURPOSE

The aim of this guideline is to provide a synopsis of best clinical practices in the rehabilitative care of adults recovering from stroke.

METHODS

Writing group members were nominated by the committee chair on the basis of their previous work in relevant topic areas and were approved by the American Heart Association (AHA) Stroke Council's Scientific Statement Oversight Committee and the AHA's Manuscript Oversight Committee. The panel reviewed relevant articles on adults using computerized searches of the medical literature through 2014. The evidence is organized within the context of the AHA framework and is classified according to the joint AHA/American College of Cardiology and supplementary AHA methods of classifying the level of certainty and the class and level of evidence. The document underwent extensive AHA internal and external peer review, Stroke Council Leadership review, and Scientific Statements Oversight Committee review before consideration and approval by the AHA Science Advisory and Coordinating Committee.

RESULTS

Stroke rehabilitation requires a sustained and coordinated effort from a large team, including the patient and his or her goals, family and friends, other caregivers (eg, personal care attendants), physicians, nurses, physical and occupational therapists, speech-language pathologists, recreation therapists, psychologists, nutritionists, social workers, and others. Communication and coordination among these team members are paramount in maximizing the effectiveness and efficiency of rehabilitation and underlie this entire guideline. Without communication and coordination, isolated efforts to rehabilitate the stroke survivor are unlikely to achieve their full potential.

CONCLUSIONS

As systems of care evolve in response to healthcare reform efforts, postacute care and rehabilitation are often considered a costly area of care to be trimmed but without recognition of their clinical impact and ability to reduce the risk of downstream medical morbidity resulting from immobility, depression, loss of autonomy, and reduced functional independence. The provision of comprehensive rehabilitation programs with adequate resources, dose, and duration is an essential aspect of stroke care and should be a priority in these redesign efforts. (Stroke.2016;47:e98-e169. DOI: 10.1161/STR.0000000000000098.).

Safety and efficacy of incobotulinumtoxinA as a potential treatment for poststroke spasticity

Spasticity is a common disabling symptom for several neurological conditions. Botulinum toxin type A injection represents the gold standard treatment for focal spasticity after stroke showing efficacy, reversibility, and low prevalence of complications. In recent years, incobotulinumtoxinA, a new Botulinum toxin type A free of complexing proteins, has been used for treating several movement disorders with safety and efficacy. IncobotulinumtoxinA is currently approved for treating spasticity of the upper limb in stroke survivors, even if several studies described the use also in lower limb muscles. In the present review article, we examine the safety and effectiveness of incobotulinumtoxinA for the treatment of spasticity after stroke.

Heat shock protein 70 overexpression does not attenuate atrophy in botulinum neurotoxin type A-treated skeletal muscle

Botulinum neurotoxin type A (BoNT/A) is used clinically to induce therapeutic chemical denervation of spastically contracted skeletal muscles. However, BoNT/A administration can also cause atrophy. We sought to determine whether a major proteolytic pathway contributing to atrophy in multiple models of muscle wasting, the ubiquitin proteasome system (UPS), is involved in BoNT/A-induced atrophy. Three and ten days following BoNT/A injection of rat hindlimb, soleus muscle fiber cross-sectional area was reduced 25 and 65%, respectively. The transcriptional activity of NF-κB and Foxo was significantly elevated at 3 days (2- to 4-fold) and 10 days (5- to 6-fold). Muscle RING-finger protein-1 (MuRF1) activity was elevated (2-fold) after 3 days but not 10 days, while atrogin-1 activity was not elevated at any time point. BoNT/A-induced polyubiquitination occurred after 3 days (3-fold increase) but was totally absent after 10 days. Proteasome activity was elevated (1.5- to 2-fold) after 3 and 10 days. We employed the use of heat shock protein 70 (Hsp70) to inhibit NF-κB and Foxo transcriptional activity. Electrotransfer of Hsp70 into rat soleus, before BoNT/A administration, was insufficient to attenuate atrophy. It was also insufficient to decrease BoNT/A-induced Foxo activity at 3 days, although NF-κB activity was abolished. By 10 days both NF-κB and Foxo activation were abolished by Hsp70. Hsp70-overexpression was unable to alter the levels of BoNT/A-induced effects on MuRF1/atrogin-1, polyubiquitination, or proteasome activity. In conclusion, Hsp70 overexpression is insufficient to attenuate BoNT/A-induced atrophy. It remains unclear what proteolytic mechanism/s are contributing to BoNT/A-induced atrophy, although a Foxo-MuRF1-ubiquitin-proteasome contribution may exist, at least in early BoNT/A-induced atrophy. Further clarification of UPS involvement in BoNT/A-induced atrophy is warranted.

Clinical and pharmacological properties of incobotulinumtoxinA and its use in neurological disorders

Background

IncobotulinumtoxinA (Xeomin^®) is a purified botulinum neurotoxin type A formulation, free from complexing proteins, with proven efficacy and good tolerability for the treatment of neurological conditions such as blepharospasm, cervical dystonia (CD), and post-stroke spasticity of the upper limb. This article provides a comprehensive overview of incobotulinumtoxinA based on randomized controlled trials and prospective clinical studies.

Summary

IncobotulinumtoxinA provides clinical efficacy in treating blepharospasm, CD, and upper-limb post-stroke spasticity based on randomized, double-blind, placebo-controlled trials with open-label extension periods (total study duration up to 89 weeks). Adverse events were generally mild or moderate. The most frequent adverse events, probably related to the injections, included eyelid ptosis and dry eye in the treatment of blepharospasm, dysphagia, neck pain, and muscular weakness in patients with CD, and injection site pain and muscular weakness when used for treating spasticity. In blepharospasm and CD, incobotulinumtoxinA was investigated in clinical trials permitting flexible intertreatment intervals based on the individual patient’s clinical need; the safety profile of intervals shorter than 12 weeks was comparable to intervals of 12 weeks and longer. There were no cases of newly formed neutralizing antibodies during the Phase III and IV incobotulinumtoxinA trials. Phase III head-to-head trials of incobotulinumtoxinA versus onabotulinumtoxinA for the treatment of blepharospasm and CD have demonstrated therapeutic equivalence of both formulations. Additional Phase III trials of incobotulinumtoxinA in conditions such as lower-limb spasticity, spasticity in children with cerebral palsy, and sialorrhea in various neurological disorders are ongoing.

Conclusion

IncobotulinumtoxinA is an effective, well-tolerated botulinum neurotoxin type A formulation. Data from randomized clinical trials and further observational studies are expected to help physicians to optimize treatment by tailoring the choice of formulation, dose, and treatment intervals to the patient’s clinical needs.

High doses of onabotulinumtoxinA in post-stroke spasticity: a retrospective analysis

We retrospectively evaluated the efficacy and safety of high doses of onabotulinumtoxinA (from 600 to 800 units) in 26 patients affected by upper and/or lower limb post-stroke spasticity. They were assessed before, 30 and 90 days after treatment. We observed a significant muscle tone reduction and a significant functional improvement (assessed with the Disability Assessment Scale). No adverse events were reported. In our retrospective analysis the treatment with high doses of onabotulinumtoxinA showed to be effective and safe.

Employment of higher doses of botulinum toxin type A to reduce spasticity after stroke

Spasticity is a common disabling symptom for several neurological conditions. Botulinum toxin type A injection represents the gold standard treatment for focal spasticity with efficacy, reversibility, and low prevalence of complications. Current guidelines suggest a dose up to 600 units (U) of onabotulinumtoxinA/incobotulinumtoxinA or up to 1,500 U of abobotulinumtoxinA to treat post-stroke spasticity to avoid important adverse effects. However, recently, higher doses of botulinum toxin type A were employed, especially in case of upper and lower limb severe spasticity. With searches of US National Library of Medicine databases, we identified all studies published from December 1989 to July 2014 concerning the use of higher doses of this neurotoxin for spasticity treatment with at least a dose of 600 U of onabotulinumtoxinA and incobotulinumtoxinA or 1,800 U of abobotulinumtoxinA. The cumulative body of evidence coming from the eight studies selected suggested that higher doses of botulinum toxin type A appeared to be efficacious in reducing spasticity of the upper and lower limbs after stroke, with adverse effects generally mild. However, further investigations are needed to determine the safety and reproducibility in larger case series or randomized clinical trials of higher doses of botulinum toxin type A also after repeated injections.