Efficacy and Safety of IncobotulinumtoxinA in the Treatment of Lower Limb Spasticity in Japanese Subjects

Botulinum toxin use in patients with post-stroke spasticity: a nationwide retrospective study from France

Background

Current guidelines recommend intramuscular botulinum toxin type A (BoNT-A) injection as first-line treatment for spasticity, a frequent and impairing feature of various central nervous system (CNS) lesions such as stroke. Patients with spasticity commonly require BoNT-A injections once every 3 to 4 months. We conducted a nationwide, population-based, retrospective cohort study, using the French National Hospital Discharge Database (PMSI), to describe BoNT-A use for spasticity in clinical practice in France between 2014 and 2020. The PMSI database covers the whole French population, corresponding to over 66 million persons.

Methods

We first searched the PMSI database for healthcare facility discharge of patients who received BoNT-A injections between 2014 and 2020, corresponding to the first set. For each BoNT-A-treated patient, we identified the medical condition for which BoNT-A may have been indicated. Another search of the PMSI database focused on patients admitted for acute stroke between 2014 and 2016 and their spasticity-related care pathway (second set). Overall, two subpopulations were analysed: 138,481 patients who received BoNT-A injections between 2014 and 2020, and 318,025 patients who survived a stroke event between 2014 and 2016 and were followed up until 2020.

Results

Among the 138,481 BoNT-A-treated patients, 53.5% received only one or two BoNT-A injections. Most of these patients (N = 85,900; 62.0%) received BoNT-A because they had CNS lesions. The number of patients with CNS lesions who received ≥1 BoNT-A injection increased by a mean of 7.5% per year from 2014 to 2019, but decreased by 0.2% between 2019 and 2020, corresponding to the COVID-19 outbreak. In stroke survivors (N = 318,025), 10.7% were coded with post-stroke spasticity, 2.3% received ≥1 BoNT-A injection between 2014 and 2020, and only 0.8% received ≥3 injections within the 12 months following BoNT-A treatment initiation, i.e., once every 3 to 4 months.

Conclusion

Our analysis of the exhaustive PMSI database showed a suboptimal implementation of BoNT-A treatment recommendations in France. BoNT-A treatment initiation and re-administration are low, particularly in patients with post-stroke spasticity. Further investigations may help explain this observation, and may target specific actions to improve spasticity-related care pathway.

Pooled Safety Analysis of IncobotulinumtoxinA in the Treatment of Neurological Disorders in Adults

The pooled incidences of treatment-emergent adverse events (TEAEs) were examined by indication using the integrated clinical database of Merz-sponsored, placebo-controlled, or repeat-dose studies of incobotulinumtoxinA in adults with cervical dystonia, blepharospasm, limb spasticity, sialorrhea, or essential tremor of the upper limb. Overall incidences of TEAEs, serious TEAEs, TEAEs leading to discontinuation, fatal TEAEs, TEAEs of special interest (TEAESIs; indicating possible toxin spread), and treatment-related (TR) events were determined for incobotulinumtoxinA and placebo after a single injection and for repeated dose cycles of incobotulinumtoxinA. The most frequent events after a single dose of incobotulinumtoxinA are summarized. After a single cycle, incidences of overall TEAEs were similar between incobotulinumtoxinA and the placebo in most indications, although between-indication differences were observed. Few TEAEs led to incobotulinumtoxinA discontinuation; there were no fatal TEAEs with incobotulinumtoxinA. In general, repeated cycles did not increase the incidence of any event. The most frequent TR-TEAEs were indication-dependent, including dysphagia for indications affecting the head or neck. The TR-TEAESIs across all indications were most commonly muscular weakness, dysphagia and dry mouth. Overall, the results of this pooled analysis support and extend the favorable safety and tolerability profile of incobotulinumtoxinA for the treatment of adult neurological disorders established by individual clinical studies.

A Pilot Study of A2NTX, a Novel Low-Molecular-Weight Neurotoxin Derived from Subtype A2 for Post-Stroke Lower Limb Spasticity: Comparison with OnabotulinumtoxinA

All the currently used type A botulinum neurotoxins for clinical uses are of subtype A1. We compared the efficacy and safety for the first time head-to-head between a novel botulinum toxin A2NTX prepared from subtype A2 and onabotulinumtoxinA (BOTOX) derived from A1 for post-stroke spasticity. We assessed the modified Ashworth scale (MAS) of the ankle joint, the mobility scores of Functional Independence Measure (FIM), and the grip power of the unaffected hand before and after injecting 300 units of BOTOX or A2NTX into calf muscles. The procedure was done in a blinded manner for the patient, the injecting physician, and the examiner. Stroke patients with chronic spastic hemiparesis (15 for A2NTX and 16 for BOTOX) were enrolled, and 11 for A2NTX and 13 for BOTOX (MAS of ankle; > or = 2) were entered for the MAS study. Area-under-curves of changes in MAS (primary outcome) were greater for A2NTX by day 30 (p = 0.044), and were similar by day 60. FIM was significantly improved in the A2NTX group (p = 0.005), but not in the BOTOX group by day 60. The hand grip of the unaffected limb was significantly decreased in the BOTOX-injected group (p = 0.002), but was unaffected in the A2NTX-injected group by day 60, suggesting there was less spread of A2NTX to the upper limb than there was with BOTOX. Being a small-sized pilot investigation with an imbalance in the gender of the subjects, the present study suggested superior efficacy and safety of A2NTX, and warrants a larger scale clinical trial of A2NTX to confirm these preliminary results.