Safety and efficacy of repeat long-term incobotulinumtoxinA treatment for lower limb or combined upper/lower limb spasticity in children with cerebral palsy

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.

The utility of selective partial neurectomy of the musculocutaneous nerve in children with bilateral spastic elbow

PURPOSE

This study aims to determine the utility of selective partial neurectomy of the musculocutaneous nerve (MCN) in pediatric patients with bilateral spastic elbow.

METHODS

A prospective, cross-sectional, case series study was performed in nine pediatric patients (four females and five males) with bilateral spastic elbow, all with a 11.4-year-old average age, where 18 selective partial neurectomies of the MCN were carried out. They were evaluated with goniometry of both spastic elbows at resting position and active amplitude, and staging spasticity employing the Modified Ashworth Scale (MAS) in the preoperative and postoperative period. The results are reported 1 year after surgery.

RESULTS

The etiology of the spasticity was secondary to cerebral palsy in eight patients (88.8%) and in one patient (11.11%) secondary to traumatic brain injury. A clinical improvement was observed in goniometry comparing the preoperative and postoperative resting position, a mean preoperative of 44.38 degrees (SD ± 7.61) versus 98.05 degrees (SD ± 24.44), respectively, and preoperative active amplitude a mean of 86.55 degrees (SD ± 15.97) versus the mean postoperative of 47.33 (SD ± 17.86). A relevant decrease on the MAS after surgical intervention was observed, resulting from an average preoperative state according to MAS of 3.78 (SD ± 0.42) to a postoperative state according to MAS of 1.44 (SD ± 0.51), these changes being statistically significant (p ≤ 0.001). No postoperative complications were observed.

CONCLUSIONS

Selective partial neurectomy of the MCN has shown good results in patients with bilateral spastic elbow in whom antispastic drugs and physical therapy have failed, and has prove permanent effects.

Spasticity-related pain in children/adolescents with cerebral palsy. Part 2 IncobotulinumtoxinA efficacy results from a pooled analysis

PURPOSE

This pooled analysis of data from three Phase 3 studies investigated the effects of incobotulinumtoxinA on spasticity-related pain (SRP) in children/adolescents with uni-/bilateral cerebral palsy (CP).

METHODS

Children/adolescents (ambulant and non-ambulant) were evaluated for SRP on increasingly difficult activities/tasks 4 weeks after each of four incobotulinumtoxinA injection cycles (ICs) using the Questionnaire on Pain caused by Spasticity (QPS; six modules specific to lower limb [LL] or upper limb [UL] spasticity and respondent type [child/adolescent, interviewer, or parent/caregiver]). IncobotulinumtoxinA doses were personalized, with all doses pooled for analysis.

RESULTS

QPS key item responses were available from 331 and 155 children/adolescents with LL- and UL-spasticity, respectively, and 841/444 (LL/UL) of their parents/caregivers. IncobotulinumtoxinA efficacy was evident with the first IC. Efficacy was sustained and became more robust with further subsequent ICs. By Week 4 of the last (i.e. fourth) IC, 33.8-53.3% of children/adolescents reported complete SRP relief from their baseline pain for respective QPS items. Children/adolescents reported reductions in mean LL SRP intensity at levels that surpassed clinically meaningful thresholds. Similarly, parents/caregivers observed complete SRP relief and less frequent SRP with incobotulinumtoxinA. Similar results were found for UL SRP.

CONCLUSION

These findings indicate that incobotulinumtoxinA could bring considerable benefit to children/adolescents with spasticity by reducing SRP, even during strenuous activities.

Safety Profile and Lack of Immunogenicity of IncobotulinumtoxinA in Pediatric Spasticity and Sialorrhea: A Pooled Analysis

IncobotulinumtoxinA, a pure botulinumtoxinA formulation, is free of accessory proteins. This analysis provides pooled safety data from phase 3 trials of children/adolescents (2–17 years), investigating incobotulinumtoxinA for the treatment of spasticity associated with cerebral palsy (at doses ≤20 U/kg (max. 500 U) per injection cycle (IC) for ≤6 ICs; three trials) or sialorrhea associated with neurologic disorders (at total doses of 20–75 U per IC for ≤4 ICs; one trial) for ≤96 weeks. Safety endpoints included the incidences of different types of treatment-emergent adverse events (TEAEs) and immunogenicity. IncobotulinumtoxinA dose groups were combined. Of 1159 patients (mean age 7.3 years, 60.4% males) treated with incobotulinumtoxinA, 3.9% experienced treatment-related TEAEs, with the most common being injection site reactions (1.3%) (both indications), muscular weakness (0.7%) (spasticity), and dysphagia (0.2%) (sialorrhea). Two patients (0.2%) experienced a treatment-related treatment-emergent serious adverse event, and 0.3% discontinued the study due to treatment-related TEAEs. No botulinumtoxinA-naïve patients developed neutralizing antibodies (NAbs) after incobotulinumtoxinA. All children/adolescents with known pre-treatment status and testing positive for Nabs at final visit (n = 7) were previously treated with a botulinumtoxinA other than incobotulinumtoxinA. IncobotulinumtoxinA was shown to be safe, with very few treatment-related TEAEs in a large, diverse cohort of children/adolescents with chronic conditions requiring long-term treatment and was without new NAb formation in treatment-naïve patients.

Spasticity-related pain in children/adolescents with cerebral palsy. Part 1: Prevalence and clinical characteristics from a pooled analysis

PURPOSE

A large prospective database from three Phase 3 studies allowed the study of spasticity-related pain (SRP) in pediatric cerebral palsy (CP).

METHODS

Baseline (pretreatment) SRP data occurring during different activities in children/adolescents (aged 2-17 years, ambulant/nonambulant) with uni-/bilateral spastic CP was obtained using the Questionnaire on Pain caused by Spasticity (QPS; six modules specific to spasticity level [lower limb (LL) or upper limb (UL)] and type of respondent [child/adolescent, interviewer, or parent/caregiver]).

RESULTS

At baseline, 331 children/adolescents with LL- and 155 with UL-spasticity completed at least one key item of their modules; LL/UL QPS modules of parent/caregivers were at least partially completed (key items) by 841/444 parents/caregivers. SRP with at least one activity at baseline was self-reported in 81.9% /69.7% (LLs/ULs) of children/adolescents with spasticity. Parents/caregivers observed LL/UL SRP behaviors in 85.9% /77.7% of their children, with multiple body regions affected. SRP negatively affected the great majority of the children in various ways. Child/adolescent-reported mean SRP intensity and parent/caregiver-observed mean SRP behavior frequencies were higher for LLs than ULs, and the level of SRP increased with more physically demanding activities.

CONCLUSION

These data suggest SRP is more common and intense in pediatric CP than generally thought, emphasizing the need for effective, long-term pain management.