Resolution of Two Steps in Botulinum Neurotoxin Serotype A1 Light Chain Localization to the Intracellular Plasma Membrane.

Botulinum neurotoxin serotype A (BoNT/A) is the most potent protein toxin to humans. BoNT/A light chain (LC/A) cleavage of the membrane-bound SNAP-25 has been well-characterized, but how LC/A traffics to the plasma membrane to target SNAP-25 is unknown. Of the eight BoNT/A subtypes (A1-A8), LC/A3 has a unique short duration of action and low potency that correlate to the intracellular steady state of LC/A, where LC/A1 is associated with the plasma membrane and LC/A3 is present in the cytosol. Steady-state and live imaging of LC/A3-A1 chimeras identified a two-step process where the LC/A N terminus bound intracellular vesicles, which facilitated an internal α-helical-rich domain to mediate LC/A plasma membrane association. The propensity of LC/A variants for membrane association correlated with enhanced BoNT/A potency. Understanding the basis for light chain intracellular localization provides insight to mechanisms underlying BoNT/A potency, which can be extended to applications as a human therapy.

Wear-Off of OnabotulinumtoxinA Effect Over the Treatment Interval in Chronic Migraine: A Retrospective Chart Review With Analysis of Headache Diaries.

OBJECTIVE: To quantify wear-off of the response to OnabotulinumtoxinA (OnabotA) treatment over the treatment cycle in chronic migraine at group and individual level. BACKGROUND: OnabotA administered quarterly is an effective treatment for chronic migraine. However, some patients report that headache recurs before the scheduled follow-up injection. METHODS: In this retrospective chart review performed in 6 university outpatient centers or private practices specialized in headache treatment, 112 patients with a ≥30% response to OnabotA who completed headache diaries over 13 weeks after OnabotA treatment were included (age [mean ± SD] 45 ± 12 years, 82% female, headache days/month at baseline 24 ± 6). RESULTS: Compared to weeks 5 to 8 after injection, headache days/week increased significantly in weeks 12 (+0.52 ± 1.96, 95% CI [0.15, 0.88], P < .009) and 13 (+1.15 ± 1.95, CI[0.79, 1.52], P < .001), demonstrating significant wear-off of the OnabotA effect. Similarly, acute medication days/week significantly increased in weeks 12 (0.38±1.67, CI [0.06, 0.69], P ≤ .027) and 13 (+0.83 ± 1.76, CI [0.49, 1.16], P < .001). At an individual level, 57 patients (51%) showed ≥30% wear-off by weeks 12 and 13, and 28 patients (25%) showed ≥30% wear-off already by weeks 10 and 11. Age, gender, OnabotA dose or cycle number, or headache center did not predict individual wear-off. CONCLUSIONS: These data show that in clinical practice, on average the response of chronic migraine patients to OnabotA injection shows a clinically significant wear-off from week 12 after treatment. About 25% of the patients experience wear-off even by weeks 10 and 11. It must be noted that wear-off detected in a real-world study on OnabotA responders can be due to wear-off of a pharmacological OnabotA effect or a placebo effect, or to regression to the mean effects. This wear-off phenomenon may negatively affect quality of life of chronic migraine patients under OnabotA treatment. The best way to counteract wear-off remains to be determined.

[Conversion ratio between different botulinum neuroprotein product in neurological practice]. / Sootnoshenie edinits deistviia razlichnykh preparatov botulinicheskogo neiroproteina pri ispol'zovanii v nevrologicheskoi praktike.

Despite nearly 30 years of experience in the application of botulinum toxin type A (BTA) in clinical practice, many fundamental questions of therapy remain valid. There are 5 botulinum toxin type A used for neurological indications in the Russian Federation in 2017. They contain different number of active neuroprotein (150 kDa) in a therapeutic dose of the drug that may have a potential impact on the efficacy and duration of action. The current SmPC of each BTA stated that the unit of activity is unique and can not be compared with any other BTA. In scientific publications one can find many details concerning the equivalence doses of onabotulinumtoxin A (botox) and abobotulinumtoxin A (dysport) and the ratio of units varies from 1:1 to 1:11. However, according to clinical guidelines, systematic reviews and high quality research evidence of recent years, the ratio of units of abobotulinumtoxin A (dysport) and onabotulinumtoxin A (botox) is 3(2,5):1. Use of a fixed ratio of units is possible only when switching from one drug to another or in case of limiting access to specific drug. Botulinum toxin type A is the first line of therapy in the treatment of several neurological diseases. The most commonly used drugs of botulinum toxin type A (botox, dysport, xeomin) have a significant evidence base that confirms their efficacy and optimal safety profile. The main difference between botulinum toxin type A is their potential activity of action, i.e., activity units and total therapeutic dose.

Design of modified botulinum neurotoxin A1 variants with a shorter persistence of paralysis and duration of action.

Botulinum neurotoxins (BoNTs) are classified by their antigenic properties into seven serotypes (A-G) and in addition by their corresponding subtypes. They are further characterized by divergent onset and duration of effect. Injections of low doses of botulinum neurotoxins cause localized muscle paralysis that is beneficial for the treatment of several medical disorders and aesthetic indications. Optimizing the therapeutic properties could offer new treatment opportunities. This report describes a rational design approach to modify the pharmacological properties by mutations in the C-terminus of BoNT/A1 light chain (LC). Toxins with C-terminal modified LC's displayed an altered onset and duration of the paralytic effect in vivo. The level of effect was dependent on the kind of the mutation in the sequence of the C-terminus. A mutant with three mutations (T420E F423M Y426F) revealed a faster onset and a shorter duration than BoNT/A1 wild type (WT). It could be shown that the C-terminus of BoNT/A1-Lc controls both onset and duration of effect. Thus, it is possible to create a mutated BoNT/A1 with different pharmacological properties which might be useful in the therapy of new indications. This strategy opens the way to design BoNT variants with novel and useful properties.

Deubiquitinating enzyme VCIP135 dictates the duration of botulinum neurotoxin type A intoxication.

Botulism is characterized by flaccid paralysis, which can be caused by intoxication with any of the seven known serotypes of botulinum neurotoxin (BoNT), all of which disrupt synaptic transmission by endoproteolytic cleavage of SNARE proteins. BoNT serotype A (BoNT/A) has the most prolonged or persistent effects, which can last several months, and exerts its effects by specifically cleaving and inactivating SNAP25. A major factor contributing to the persistence of intoxication is the long half-life of the catalytic light chain, which remains enzymatically active months after entry into cells. Here we report that BoNT/A catalytic light chain binds to, and is a substrate for, the ubiquitin ligase HECTD2. However, the light chain evades proteasomal degradation by the dominant effect of a deubiquitinating enzyme, VCIP135/VCPIP1. This deubiquitinating enzyme binds BoNT/A light chain directly, with the two associating in cells through the C-terminal 77 amino acids of the light chain protease. The development of specific DUB inhibitors, together with inhibitors of BoNT/A proteolytic activity, may be useful for reducing the morbidity and public health costs associated with BoNT/A intoxication and could have potential biodefense implications.

Key Parameters for the Use of AbobotulinumtoxinA in Aesthetics: Onset and Duration.

Time to onset of response and duration of response are key measures of botulinum toxin efficacy that have a considerable influence on patient satisfaction with aesthetic treatment. However, there is no overall accepted definition of efficacy for aesthetic uses of botulinumtoxinA (BoNT-A). Mechanical methods of assessment do not lend themselves to clinical practice and clinicians rely instead on assessment scales such as the Frontalis Activity Measurement Standard, Frontalis Rating Scale, Wrinkle Severity Scale, and Subject Global Assessment Scale, but not all of these have been fully validated. Onset of activity is typically seen within 5 days of injection, but has also been recorded within 12 hours with abobotulinumtoxinA. Duration of effect is more variable, and is influenced by parameters such as muscle mass (including the effects of age and sex) and type of product used. Even when larger muscles are treated with higher doses of BoNT-A, the duration of effect is still shorter than that for smaller muscles. Muscle injection technique, including dilution of the toxin, the volume of solution injected, and the positioning of the injections, can also have an important influence on onset and duration of activity. Comparison of the efficacy of different forms of BoNT-A must be made with the full understanding that the dosing units are not equivalent. Range of equivalence studies for abobotulinumtoxinA (Azzalure; Ipsen Limited, Slough UK/Galderma, Lausanne CH/Dysport, Ipsen Biopharm Limited, Wrexham UK/Galderma LP, Fort Worth, TX) and onabotulinumtoxinA (Botox; Allergan, Parsippany, NJ) have been conducted, and results indicate that the number of units of abobotulinumtoxinA needs to be approximately twice as high as that of onabotulinumtoxinA to achieve the same effect. An appreciation of the potential influence of all of the parameters that influence onset and duration of activity of BoNT-A, along with a thorough understanding of the anatomy of the face and potency of doses, are essential to tailoring treatment to individual patient needs and expectations.

The Effect of Albumin and Platelet-Poor Plasma Supplemented Botulinum A Toxin on Bioavaliability: An Experimental Rabbit Model.

Today, botulinum toxin is commonly used for cosmetic purposes throughout the world. Despite various agents reducing the efficiency of toxin are well defined, the studies related to increasing the bioavailability are limited. The purpose of our study is to assess the effect of the preparation of toxin by diluting with platelet-poor plasma (PPP) and/or albumin instead of standard dilution (saline) on bioavailability in cosmetic-purpose botulinum toxin applications.In the study, 24 New Zealand rabbits were used. Right anterior auricular muscle was preferred for toxin injections. Subjects were divided in 4 groups and in every group; botulinum A toxin (BTxA) that was prepared by different dilution methods was injected. 2.5 U saline-diluted BTxA was injected to the subjects in group 1, 2.5 U ready-to-use rabbit albumin-diluted BTxA was injected to group 2 and 2.5 U autologous PPP-diluted BTxA was injected to group 3 and pure saline was injected to group 4.Before the injection (0th week) and in the second, sixth, and 12th weeks after the injection, visual and electroneuromyographic evaluations of the ears of the subjects were performed.In the second week, median amplitude levels in group 2 were significantly found lower than other groups.In the sixth week, median amplitude levels in group 1 were significantly found lower than other groups.In 12th week, no significant difference was found among all the groups in terms of median amplitude levels.Visual findings were also correlated with electroneuromyographic findings.It was observed that the dilution of BTxA with albumin had caused a stronger paralysis when compared to dilution with saline or PPP at the beginning (second week); however, in the following weeks (sixth week), it was seen that dilution with saline had maintained paralysis better when compared with other dilution methods.In cosmetic BTxA applications, dilution of the toxin with albumin or PPP instead of standard dilution has no positive effect on bioavailability and such modifications regarding this kind of dilution are found unsuitable. Further studies are needed to directly relate the results with clinical applications.

Pre-Clinical Study of a Novel Recombinant Botulinum Neurotoxin Derivative Engineered for Improved Safety.

Cyto-012 is a recombinant derivative of Botulinum neurotoxin Type A (BoNT/A). It primarily differs from wild type (wt) BoNT/A1 in that it incorporates two amino acid substitutions in the catalytic domain of the light chain (LC) metalloprotease (E224 > A and Y366 > A), designed to provide a safer clinical profile. Cyto-012 is specifically internalized into rat cortical and hippocampal neurons, and cleaves Synaptosomal-Associated Protein 25 (SNAP-25), the substrate of wt BoNT/A, but exhibits slower cleavage kinetics and therefore requires a higher absolute dose to exhibit pharmacologic activity. The pharmacodynamics of Cyto-012 and wt BoNT/A have similar onset and duration of action using the Digital Abduction Assay (DAS). Intramuscular LD50 values for Cyto-012 and wt BoNT/A respectively, were 0.63 ug (95% CI = 0.61, 0.66) and 6.22 pg (95% CI = 5.42, 7.02). ED50 values for Cyto-012 and wt BoNT/A were respectively, 0.030 ug (95% CI = 0.026, 0.034) and 0.592 pg (95% CI = 0.488, 0.696). The safety margin (intramuscular LD50/ED50 ratio) for Cyto-012 was found to be improved 2-fold relative to wt BoNT/A (p < 0.001). The DAS response to Cyto-012 was diminished when a second injection was administered 32 days after the first. These data suggest that the safety margin of BoNT/A can be improved by modulating their activity towards SNAP-25.

Aplicaciones clínicas de la toxina botulínica en el estrabismo: estudio de las inyecciones realizadas durante un año en un hospital general / Botulinum toxin uses in strabismus: A review of the injections performed during one year in a general hospital

OBJETIVO: Analizar las indicaciones, dosis y eficacia de las inyecciones de toxina botulínica A en el departamento de Estrabología. MÉTODO: En este estudio prospectivo, 28 pacientes diagnosticados de estrabismo fueron tratados con toxina botulínica. Se recopilaron los pacientes tratados en 2013 en el Hospital Rey Juan Carlos (Móstoles) para estudiar las indicaciones, la dosis empleada, y se analizaron los resultados de la última revisión, tanto en niños como en adultos, con un seguimiento mínimo de 14 meses. RESULTADOS: Se recogieron datos de 11 niños, 6 mujeres (54,5%), y 17 adultos, 11 varones (64%). La edad media fue 4,42 ± 3,48 años y 58,71 ± 18,07 años en niños y adultos respectivamente. En ambos grupos la mayoría de los casos eran endotropias (81,8% en niños y 47,1% en adultos), aunque el grupo de adultos presentaba enfermedades más heterogéneas incluyendo 4 pacientes con exotropía (26,5%), 4 con hipertropía (26,5%) y uno con nistagmo aislado (5,9%). La media de inyecciones en niños fue de 1,45 ± 0,93, aunque el 72,7% recibieron una única inyección; en el grupo de adultos la media de inyecciones fue de 3,27 ± 1,41. Se encontró una diferencia estadísticamente significativa en la comparación de tropia y foria prepostinyección en niños y adultos (p < 0,05). En ambos grupos hubo una mejoría significativa en el tortícolis postinyección comparado con el previo (p < 0,05). En 4 niños pudimos detectar una mejoría en la estereoagudeza. Dos niños (18,2%) y 5 adultos (29,4%) precisaron intervención quirúrgica posterior. Ocho adultos (49,1%) presentaban diplopia en posición primaria de la mirada, que se resolvió en 6 casos con inyecciones de toxina, pero 2 necesitaron cirugía para la corrección de la diplopia. Las diferencias entre tropia y foria pre- y postintervención fueron estadísticamente significativas (p < 0,05), así como las diferencias entre el tortícolis pre- y postinyección. En 4 casos se pudo detectar mejoría en la estereoagudeza. CONCLUSIONES: La toxina botulínica es un fármaco muy útil en el estrabismo, con mejores resultados sensoriales y motores en los niños, pero eficaz como tratamiento sintomático en algunos casos de estrabismo en adultos

OBJECTIVE: To analyse the indications, dosage and efficacy of botulinum toxin A injection performed in patients in a Strabismus Department. METHODS: In this prospective study, botulinum toxin A was injected into 28 patients diagnosed with strabismus. Data was obtained from the records of patients that were evaluated during 2013 in the Strabismus Unit of Rey Juan Carlos Hospital (Móstoles, Madrid, Spain) in order to assess the indications and dosage of botulinum toxin A use in strabismus, as well as its clinical effect and differences in paediatric and adult patients. The outcomes in the last visit, at least 14 months after the injections, were analysed. RESULTS: An analysis was performed on the data from 11 children, 6 females (54.5%), and 17 adults, 11 males (64%). The mean age was 4.42 ± 3.48 years and 58.71 ± 18.07 years in the children and adult groups, respectively. The majority of cases in both groups were esotropia (81.8% in children and 47.1% in adults). However the pathologies in the adult group were quite heterogeneous, including 4 patients with exotropia (26.5%), 4 with hypertropia (26.5%), and one with isolated nystagmus (5.9%). The mean number of the botulinum toxin injections in children was 1.45 ± 0.93, although 72.7% received a single injection. In the adult group, the mean number of injections was 3.27 ± 1.41. There was a statistically significant difference between pre- and post-injection in the tropia and phoria measurements in children and adults group (P<.05). In both groups there was a statistically significant improvement in post-injection torticollis when compared with the pre-injection measurement (P<.05). An improvement in the stereoacuity could be detected in 4 children. Two children (18.2%) and 5 adults (29.4%) required subsequent surgical intervention. Eight adult patients (49.1%) complained of diplopia in the primary position, which was resolved in 6 cases with toxin injection, whereas 2 needed surgery for diplopia correction. CONCLUSIONS: Botulinum toxin is a very useful tool in the management of strabismus, obtaining better sensory and motor results in children, but it is also effective as a symptomatic treatment in some types of strabismus in adults

Pharmacokinetics and pharmacodynamics of incobotulinumtoxinA influencing the clinical efficacy in post-stroke spasticity.

INTRODUCTION: Post-stroke spasticity is a disabling neurological condition and may have a significant impact on quality of life. Ability to carry out activities of daily living is often compromised and painful contractures in the affected limbs may also develop. The prevalence of spasticity may be as high as 40% within the first year after the initial stroke event. Management of this condition focuses on improving muscle tone, function and pain. IncobotulinumtoxinA is effective in treating focal spasticity. AREAS COVERED: This review will summarize outcomes from incobotulinumtoxin A phase III trials in upper limb spasticity. Pharmacodynamics and pharmacokinetics will also be discussed along with future studies and possible indications. Literature searches used for this review include; PubMed and www.clinicaltrials.gov searches. Congress abstracts and case reports are not included. EXPERT OPINION: IncobotulinumtoxinA, is a 150 kiloDalton neurotoxin without complexing proteins and is well tolerated in patients with spasticity. There is an 80% improvement reported on spasticity and disability in several phase III studies. In the future, higher doses for upper and lower limb spasticity may be considered. Antibody formation does not seem to limit the administration of higher doses. Prospective studies are evaluating the efficacy of incobotulinumtoxin in children and adolescents with cerebral palsy. Furthermore, the clinical efficacy and immunogenic status of other botulinum neurotoxin A subtypes are currently under investigation.

Retrograde transport of radiolabelled botulinum neurotoxin type A to the CNS after intradetrusor injection in rats.

OBJECTIVE: To investigate the potential distribution of radiolabelled botulinum neurotoxin type A (BoNT/A) in the CNS after bladder injection in normal rats, by using the gamma-emitting radionuclide technetium-99 m ((99m) Tc). MATERIALS AND METHODS: BoNT/A was radiolabelled by pretreatment with 2-iminothiolane and incubation with (99m) Tc-gluconate. The labelled toxin (99m) Tc-BoNT/A was purified using size exclusion HPLC. Twenty-four female Wistar rats were evenly injected in the bladder wall with either (99m) Tc-ΒοΝΤ/Α (n = 12) or free (99m) Tc (n = 12). Four rats from each group were killed at 1, 3 and 6 h after injection, respectively. The bladder, L6-S1 spinal cord segment and L6-S1 dorsal root ganglia (DRG) were harvested and their radioactivity counted in a gamma scintillation detector. Results were calculated as % injected dose (I.D.) per gram of tissue. The paired t-test was used for comparison of means of (99m) Tc-ΒοΝΤ/Α radioactivity vs free (99m) Tc in the tissues of interest. RESULTS: Radiolabelled BoNT/A had a high radiochemical stability of 70% after 24 h. Gradual accumulation of (99m) Tc-ΒοΝΤ/Α was observed in the DRG up to 6 h after injection (P = 0.04 and P = 0.029 compared with 1 h and 3 h, respectively), while no accumulation was detected for free (99m) Tc. Consequently, (99m) Tc-ΒοΝΤ/Α radioactivity in the DRG was higher than free (99m) Tc radioactivity (3.18 ± 0.67% I.D./g vs 0.19 ± 0.10% I.D./g [P = 0.002] 6 h after injection). Values for (99m) Tc-ΒοΝΤ/Α radioactivity in the spinal cord were higher than those for free (99m) Tc, but not significantly. The bladder retained higher dosages of (99m) Tc-ΒοΝΤ/Α than free (99m) Tc at all time points. CONCLUSIONS: Significant accumulation of the radiolabelled toxin in the lumbosacral DRG, together with a less significant uptake in the respective spinal cord segment as opposed to free radioactivity provide first evidence of the retrograde transport of BoNT/A to the CNS after bladder injection in rats.

Activity of botulinum toxin type A in cranial dura: implications for treatment of migraine and other headaches.

BACKGROUND AND PURPOSE: Although botulinum toxin type A (BoNT/A) is approved for chronic migraine treatment, its mechanism of action is still unknown. Dural neurogenic inflammation (DNI) commonly used to investigate migraine pathophysiology can be evoked by trigeminal pain. Here, we investigated the reactivity of cranial dura to trigeminal pain and the mechanism of BoNT/A action on DNI. EXPERIMENTAL APPROACH: Because temporomandibular disorders are highly comorbid with migraine, we employed a rat model of inflammation induced by complete Freund's adjuvant, followed by treatment with BoNT/A injections or sumatriptan p.o. DNI was assessed by Evans blue-plasma protein extravasation, cell histology and RIA for CGRP. BoNT/A enzymatic activity in dura was assessed by immunohistochemistry for cleaved synaptosomal-associated protein 25 (SNAP-25). KEY RESULTS: BoNT/A and sumatriptan reduced the mechanical allodynia and DNI, evoked by complete Freund's adjuvant. BoNT/A prevented inflammatory cell infiltration and inhibited the increase of CGRP levels in dura. After peripheral application, BoNT/A-cleaved SNAP-25 colocalized with CGRP in intracranial dural nerve endings. Injection of the axonal transport blocker colchicine into the trigeminal ganglion prevented the formation of cleaved SNAP-25 in dura. CONCLUSIONS AND IMPLICATIONS: Pericranially injected BoNT/A was taken up by local sensory nerve endings, axonally transported to the trigeminal ganglion and transcytosed to dural afferents. Colocalization of cleaved SNAP-25 and the migraine mediator CGRP in dura suggests that BoNT/A may prevent DNI by suppressing transmission by CGRP. This might explain the effects of BoNT/A in temporomandibular joint inflammation and in migraine and some other headaches.

Long-term sequelae treatment of peripheral facial paralysis with botulinum toxin type A: Repartition and kinetics of doses used.

STUDY OBJECTIVES: Botulinum toxin is a key therapeutic tool in the comprehensive treatment of peripheral facial paralysis. It fights spasms, synkinesis and overactivity of the different skin muscles responsible of facial expressions. Even though injection techniques as well as target muscles have been well identified, doses used remain quite imprecise and often not detailed muscle by muscle, further more dosage progression has not been monitored over time. Our retrospective study is the first one to refine the repartition of botulinum toxin doses on each of the relevant skin muscles and assess dosage kinetics. PATIENTS AND METHODS: Thirty patients were included since 2008 with a mean follow-up of 2.3years. Each patient had at least 3 injections, with a delay of 4 to 6months between each injection. RESULTS: Mean doses are indicated for each muscle injected on the paralyzed and healthy sides. Dose kinetics suggests an initial dosage increase after the first injection followed by a decrease over time. No treatment resistance was observed. CONCLUSION: Our study represents a didactic help in using botulinum toxin for sequelae of peripheral facial paralysis by providing more details on the effective mean doses for each muscle and their progression over time.

TAT-BoNT/A(1₋448), a novel fusion protein as a therapeutic agent: analysis of transcutaneous delivery and enzyme activity.

Botulinum neurotoxin type A (BoNT/A) has been used as an injectable therapeutic agent for the treatment of some abnormal muscle contractions. In this study, TAT(47-57) peptide, a cell-penetrating peptide, was fused with the catalytic domain of BoNT/A for therapeutic purposes. HeLa and BE(2)-C cell lines were treated separately with purified TAT-BoNT/A(1-448) recombinant protein, and transduction of protein was analyzed by western blotting. Also, transcutaneous delivery through mouse skin surface was evaluated by immunohistochemistry. The in vitro catalytic activity of TAT-BoNT/A(1-448) was evaluated by HPLC. The presence of recombinant protein was detected in both of the cell lines as well as mouse skin cryosections after 60 and 120 min of incubation. The concentration of intracellular proteins was increased over time. HPLC analysis showed that this fusion protein has a biological activity 1.5 times as much as the full-length BoNT/A(1-448) protein. TAT-BoNT/A(1-448) fusion protein is biologically active and can transmit through living cells in vitro and in vivo successfully and more effectively compared with BoNT/A(1-448) protein as control.

A Randomized, Double-Blind Trial to Investigate the Equivalence of IncobotulinumtoxinA and OnabotulinumtoxinA for Glabellar Frown Lines.

BACKGROUND: IncobotulinumtoxinA and onabotulinumtoxinA are indicated for the temporary improvement in the appearance of glabellar frown lines (GFL). This is the first randomized direct comparator study to date, at the Food and Drug Administration-recommended dose of 20 units (U), for the treatment of GFL. OBJECTIVE: To investigate the dose equivalence of incobotulinumtoxinA (20 U) and onabotulinumtoxinA (20 U) for the treatment of moderate-to-severe GFL. MATERIALS AND METHODS: Prospective, randomized (1:1), double-blinded, parallel-group study in 250 females (18-50 years), employing a single treatment with incobotulinumtoxinA or onabotulinumtoxinA, followed by a 4-month observational period. RESULTS: At the primary efficacy endpoint (1 month after treatment), incobotulinumtoxinA was equivalent to onabotulinumtoxinA in the treatment of GFL at the 20 U dose within the prespecified ± 15% margin of equivalence. Efficacy remained similar between treatment groups through 4 months after treatment as assessed by the independent masked panel and the masked treating physicians. Patient satisfaction ratings were similar between groups and favorable (>90%) throughout. Both treatments were well tolerated. CONCLUSION: Equivalence was demonstrated at the primary endpoint between incobotulinumtoxinA and onabotulinumtoxinA in the treatment of GFL at the 20 U dose at 1 month. Similar efficacy and tolerability profiles were observed through 4 months after treatment.

Delayed contrast-enhanced MRI to localize Botox after cystoscopic intravesical injection.

PURPOSE: There is a lack of studies to show localization of botulinum toxins (BoNT) within bladder wall and/or absorption rates. Our study examined the later distribution of BoNTA/gadolinium within the bladder wall by performing a delayed MRI scan after intravesical injection. This potentially may help to explain the level and mechanism at which BoNT may be producing its effect. METHODS: A prospective study enrolled 20 consecutive patients with neuropathic or idiopathic overactive bladders. The Aim of the study was to perform MRI 3 h post procedure. Botox 100-200 IU was reconstituted with 19 ml saline and 1 ml of gadolinium contrast. Intradetrusor injections were administered using a rigid 21F cystoscope with a total of 20 injections into bladder wall, including two into the trigone. The depth of injection was approximately 2 mm, without raising a bleb. One radiologist reviewed films and reported on the number of bladder walls with contrast, location, the presence of extravesical extravasation, contrast in distal ureter(s), and bladder wall thickness. RESULTS: Ninety percentage of patients had contrast within bladder wall. There was a variation in the number of bladder walls involved; 85 % had contrast seen in at least two walls. Also, a variation was noted in the extent of extravasation; 80 % showed some evidence. CONCLUSIONS: Diffusion of BoNT after intravesical injection is very common once bladder wall is breeched. Precise injection localization into muscle layer may not be as relevant to outcome as previously assumed. The assumption in our study that localization and diffusion of contrast also represents the localization of BoNT is open to critique as BoNT diffusion is potentially slower (Mehnert et al. in World J Urol 27(3):397-403, 2009). The absence of systemic symptoms after the injection in our series supports guidelines concerning the safety of procedure.

Regional diffusion of botulinum toxin in facial muscles: a randomised double-blind study and a consideration for clinical studies with split-face design.

Despite the extensive use of botulinum toxin A (BoNTA) in medical and cosmetic treatments, the potential spreading of BoNTA to surrounding tissues remains unknown. A patient with hemifacial paralysis upon blepharospasm treatment with low dose of BoNTA, prompted us to investigate the spreading effect. A randomised, double-blind study was conducted in which 5 healthy women (33-52 years) were treated with different doses of onabotulinum toxin unilaterally in the corrugator muscle. Parameters of efficacy and diffusion (CMAP; EMG and jitter analysis) in both glabellar and frontalis muscles were assessed at baseline, 2 and 4 weeks following BoNTA injection. CMAP of the treated glabellar muscles was reduced to approximately 40% in all dose groups. Additionally, contralateral CMAP reduction was observed in 3 of 5 subjects. These data confirm regional diffusion of BoNTA in facial muscle application, which raises question on the reliability of split-face models in BoNTA studies.