To switch from Botox to Dysport in children with CP, a real world, dose conversion, cost-effectiveness study

The cost-effectiveness of abobotulinumtoxinA (Dysport) and onabotulinumtoxinA (Botox) for managing spasticity of the upper and lower limbs, and cervical dystonia

OBJECTIVE

To evaluate the costs and benefits associated with the use of abobotulinumtoxinA (aboBoNT-A) and onabotulinumtoxinA (onaBoNT-A) for lower limb spasticity in children, upper and lower limb spasticity in adults, and cervical dystonia in adults.

METHODS

This pharmacoeconomic analysis compared aboBoNT-A with onaBoNT-A. A decision tree model with a 1-year time horizon was conducted from a UK National Health Service (NHS) perspective using data from a variety of sources: randomized controlled trials (RCTs), network meta-analyses (NMAs), observational studies, and a physician survey investigating treatment patterns and resource utilization. Four patient populations were included: pediatric patients with lower limb spasticity (PLL), and adults with upper limb spasticity (AUL), lower limb spasticity (ALL), and cervical dystonia (CD). Outcomes included costs, quality-adjusted life years (QALYs) gained, cost per responder, and incremental cost per QALY gained. The effectiveness of each treatment was evaluated as a response to treatment. The base case assumption was that all patients in the model continued to receive botulinum toxin type A (BoNT-A) treatments at regular intervals regardless of treatment response status. Scenario analysis evaluated the impact of discontinuing BoNT-A for patients without a response to the first injection.

RESULTS

The model found that aboBoNT-A resulted in greater quality-of-life and lower costs compared with onaBoNT-A for the management of spasticity and CD in all included indications. Across populations, cost savings ranged from £304 to £3,963 and QALYs gained ranged from 0.010 to 0.02 over a 1-year time horizon. Results were robust to scenario analyses and were driven by the impact of treatment response on health-related quality-of-life.

CONCLUSIONS

AboBoNT-A was associated with higher treatment response, improved quality-of-life, and reduced costs in spasticity and CD versus onaBoNT-A. These findings could help deliver more effective and efficient healthcare in the NHS.

A consensus statement on the use of botulinum toxin in pediatric patients

Botulinum toxin has been used in medicine for the past 30 years. However, there continues to be controversy about the appropriate uses and dosing, especially in the pediatric population. A panel of nine pediatric physiatrists from different regions and previous training programs in the United States were nominated based on institutional reputation and botulinum toxin (BoNT) experience. Based on a review of the current literature, the goal was to provide the rationale for recommendations on the administration of BoNT in the pediatric population. The goal was not only to review safety, dosing, and injection techniques but also to develop a consensus on the appropriate uses in the pediatric population. In addition to upper and lower limb spasticity, the consensus also provides recommendations for congenital muscular torticollis, cervical dystonia, sialorrhea, and brachial plexus palsies.

A First Clinical Trial on Botulinum Toxin-A for Chronic Muscle-Related Pain in Cerebral Palsy

Objective: To test if botulinum toxin-A (BoNT-A) is effective in reducing chronic muscle-related pain in adults with spastic cerebral palsy (CP), as compared to placebo.

Design: A single-center, double-blind, parallel, randomized placebo-controlled trial. The design included an interim analysis to allow for confirmatory analysis, as well as pilot study outcomes.

Setting: Tertiary university hospital.

Participants: Adults with spastic CP and chronic pain associated with spastic muscle(s).

Intervention: Treatment was one session of electromyographically guided intramuscular injections of either BoNT-A or placebo normosaline.

Main Study Outcomes: The primary outcome was the proportion who achieved a reduction of pain intensity of two or more steps on the Numerical Rating Scale 6 weeks after treatment.

Results: Fifty individuals were screened for eligibility, of whom 16 were included (10 female, 6 male, mean age = 32 years, SD = 13.3 years). The randomization yielded eight participants per treatment arm, and all completed the study as randomized. The study was stopped at the interim analysis due to a low probability, under a preset threshold, of a positive primary outcome. Four individuals were treatment responders in the BoNT-A group for the primary outcome compared to five responders in the placebo group (p = 1.000). Adverse events were mild to moderate. In exploratory analysis, the BoNT-A group had a trend of continuing reduction of pain at the last follow-up, after the primary endpoint.

Conclusions: This study did not find evidence that BoNT-A was superior to placebo at the desired effect size (number needed to treat of 2.5) at 6 weeks after treatment.

Trial registration:ClinicalTrials.gov: NCT02434549

Cost effectiveness and impact on quality of life of abobotulinumtoxinA and onabotulinumtoxinA in the treatment of children with lower limb spasticity in Canada

Background: Injectable botulinum neurotoxins are a mainstay of treatment for pediatric spasticity. AbobotulinumtoxinA and onabotulinumtoxinA are both injectable toxin therapies used to treat pediatric lower limb (PLL) spasticity in Canada. The objective of this study was to assess the cost-effectiveness of abobotulinumtoxinA vs. onabotulinumtoxinA in the treatment of PLL spasticity in Canada.Methods: A probabilistic Markov cohort model with a 2-year time horizon was developed, with health states defined by response to therapy, as characterized by the goal attainment scale (GAS). Based on randomized controlled trial evidence, response to therapy was similar or higher for abobotulinumtoxinA relative to onabotulinumtoxinA; uncertainty was incorporated into model parameters, however, as the two therapies have not been compared head-to-head. Canadian resource use and cost data were incorporated.Results: In the base case, abobotulinumtoxinA generated 1.48 quality-adjusted life years over the model time horizon, compared to 1.47 for onabotulinumtoxinA. AbobotulinumtoxinA was associated with cost savings of $123 CAD, reflecting lower costs in both medication acquisition and health services. The estimated improvement to quality of life and reduced costs result in an estimate of economic dominance for abobotulinumtoxinA over onabotulinumtoxinA. This dominant result persisted across probabilistic and scenario analyses.Key points for decision makersBased on a review of available clinical evidence, abobotulinumtoxinA was found to have significant and/or numerical efficacy benefits to onabotulinumtoxinA on functional outcomes (Goal Attainment Scale) and tone (Modified Ashworth Scale) and in the treatment of pediatric lower limb spasticityIn this cost-effectiveness analysis, abobotulinumtoxinA was found to be associated with greater quality-adjusted life years and lower costs than onabotulinumtoxinA (economically dominant)A limitation of this analysis was the uncertainty around key parameters. Specifically, the lack of head-to-head comparison data for the two therapies, and variable data regarding likely onabotulinumtoxinA dosing in PLL in clinical practice. However, across a range of plausible scenarios, the economic dominant result remained.

Frequency and risk factors of antibody-induced secondary failure of botulinum neurotoxin therapy

Objective

To investigate the risk factors of neutralizing antibody (NAB)–induced complete secondary treatment failure (cSTF) during long-term botulinum neurotoxin (BoNT) treatment in various neurologic indications.

Methods

This monocenter retrospective cohort study analyzed the data of 471 patients started on BoNT therapy between 1995 and 2015. Blood samples of 173 patients were investigated for NABs using the mouse hemidiaphragm test (93 with suspected therapy failure, 80 prospective study participants). The frequency of NAB-cSTF was assessed for various indications: hemifacial spasm, blepharospasm, cervical dystonia, other dystonia, and spasticity. A priori defined potential risk factors for NAB-cSTF were evaluated, and a stepwise binary logistic regression analysis was performed to identify independent risk factors.

Results

Treatment duration was 9.8 ± 6.2 years (range, 0.5–30 years; adherence, 70.6%) and number of treatment cycles 31.2 ± 22.5 (3–112). Twenty-eight of 471 patients (5.9%) had NAB-cSTF at earliest after 3 and at latest after 103 treatment cycles. None of the 49 patients treated exclusively with incobotulinumtoxinA over 8.4 ± 4.2 (1–14) years developed NAB-cSTF. Independent risk factors for NAB-cSTF were high BoNT dose per treatment, switching between onabotulinumtoxinA and other BoNT formulations (except for switching to incobotulinumtoxinA), and treatment of neck muscles.

Conclusions

We present a follow-up study with the longest duration to date on the incidence of NAB-cSTF in patients treated with various BoNT formulations, including incobotulinumtoxinA. Whereas the overall risk of NAB-cSTF is low across indications and BoNT formulations, our findings underpin the recommendations to use the lowest possible dose particularly in cervical dystonia, and to avoid unnecessary switching between different formulations.

Contemporary Review and Case Report of Botulinum Resistance in Facial Synkinesis

BACKGROUND

Botulinum resistance poses significant treatment challenges for both patients and healthcare practitioners. We first present a case highlighting botulinum resistance in a patient who failed to respond to alternative formulations but who responded remarkably to incobotulinum toxinA, an identical toxin free of complexing proteins. Secondly, we provide a treatment algorithm and a review of the literature detailing clinical and immunochemical botulinum resistance.

RESULTS

Patients with botulinum resistance show a predisposition to failure on subsequent injections and possess a propensity toward neutralizing and nonneutralizing antibody development. The mechanisms of resistance are not entirely understood but thought to be secondary to an immunologic response. Risk factors for resistance include higher botulinum doses, more frequent injections, and high total lifetime dosage. Patients may still respond to other botulinum formulations or subtypes; however, this effect may be temporary.

CONCLUSION

This case report describes a patient who responded to incobotulinum toxinA after failing treatment with the identical toxin compounded with buffer proteins, ultimately supporting the possibility of immune-mediated resistance to the surrounding proteins and not the toxin itself. Often, impending treatment resistance is preceded by a poor or limited clinical response. Antibody testing is not indicated because it is neither sensitive nor specific and does not change clinical practice. Initially, higher doses of botulinum may overcome resistance without increasing treatment frequency, and side effects are far less common in those with clinical resistance. If higher dosages fail to produce a response, alternative botulinum formulations or subtypes can be considered. Laryngoscope, 129:2269-2273, 2019.