A pharmacodynamic comparison study of different botulinum toxin type A preparations

Model-based interspecies interpretation of botulinum neurotoxin type A on muscle-contraction inhibition

Botulinum neurotoxins (BoNTs) are commonly used in therapeutic and cosmetic applications. One such neurotoxin, BoNT type A (BoNT/A), has been studied widely for its effects on muscle function and contraction. Despite the importance of BoNT/A products, determining the blood concentrations of these toxins can be challenging. To address this, researchers have focused on pharmacodynamic (PD) markers, including compound muscle action potential (CMAP) and digit abduction scoring (DAS). In this study, we aimed to develop a probabilistic kinetic-pharmacodynamic (K-PD) model to interpret CMAP and DAS data obtained from mice and rats during the development of BoNT/A products. The researchers also wanted to gain a better understanding of how the estimated parameters from the model relate to the bridging of animal models to human responses. We used female Institute of Cancer Research mice and Sprague-Dawley (SD) rats to measure CMAP and DAS levels over 32 weeks after administering BoNT/A. We developed a muscle-contraction inhibition model using a virtual pharmacokinetic (PK) compartment combined with an indirect response model and performed model diagnostics using goodness-of-fit analysis, visual predictive checks (VPC), and bootstrap analysis. The CMAP and DAS profiles were dose-dependent, with recovery times varying depending on the administered dose. The final K-PD model effectively characterized the data and provided insights into species-specific differences in the PK and PD parameters. Overall, this study demonstrated the utility of PK-PD modeling in understanding the effects of BoNT/A and provides a foundation for future research on other BoNT/A products.

The efficacy and safety of neubotulinumtoxinA for the treatment of forehead horizontal lines in Asians - A clinical, prospective, interventional, split-face study

BACKGROUND

Botulinum toxin injections are widely sought after in the field of medical aesthetics, offering consumers a variety of brand choices. Two commonly available botulinum toxin products, onabotulinumtoxinA and neubotulinumtoxinA, are featured in numerous clinics, leading many to question whether there are discernible differences in results, given their varying price ranges.

OBJECTIVE

To evaluate the efficacy and safety of neubotulinumtoxinA for the treatment of forehead horizontal lines.

METHODS

A 12-week prospective, single-centre, interventional split-face study was conducted, including 30 subjects. These enrolled subjects received a single treatment session, with neubotulinumtoxinA applied to the left side of the forehead and onabotulinumtoxinA to the right side. A superficial injection was performed in all individuals, where the product was injected subdermally in the frontalis muscle. Evaluation was conducted at baseline, 7 days, 14, days and 4, 8, and 12 weeks after treatment, both when the eyebrows were at maximum lift and in a resting position. Treatment efficacy was assessed by two physicians and self-assessed by the patients, using the Fitzpatrick Wrinkle Classification system. Adverse events were documented to evaluate safety.

RESULTS

The study found no statistically significant difference in the efficacy of neubotulinum and onabotulinum for treating forehead wrinkles, as indicated by p-values above 0.05 for both static and dynamic conditions. No safety and adverse events were observed in both formulations.

CONCLUSION

This study has demonstrated that neither formulation is inferior to each other in the treatment of forehead horizontal lines.

A Phase 3, Randomized, Multi-center Clinical Trial to Evaluate the Efficacy and Safety of Neu-BoNT/A in Treatment of Primary Axillary Hyperhidrosis

BACKGROUND

Botulinum toxin type A is widely used to treat primary axillary hyperhidrosis and has proven to be an effective and safe approach. Onabotulinumtoxin A was approved by the FDA as a treatment for primary axillary hyperhidrosis. This study aimed to evaluate the efficacy and safety of Neu-BoNT/A in subjects diagnosed with primary axillary hyperhidrosis.

METHODS

The Hyperhidrosis Disease Severity Scale, gravimetric measurement of sweat, and Global Assessment Scale were analyzed at weeks 4, 8, 12, and 16 to determine the effect of treatment. Adverse events, physical examination, and vital signs were monitored.

RESULTS

Subjects treated with Neu-BoNT/A showed statistically significant improvement by all 3 methods at weeks 4, 8, 12, and 16 (P value = 0.00). There were no severe adverse events or significant changes in vital signs, physical examination, or laboratory tests.

CONCLUSION

Neu-BoNT/A can be effectively and safely used for primary axillary hyperhidrosis.

LEVEL OF EVIDENCE II

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Comparative Pharmacodynamics Study of 3 Different Botulinum Toxin Type A Preparations in Mice

A new complexing protein-free botulinum toxin Type A (CBoNT) with the same mechanism of action as the botulinum toxin complex onabotulinumtoxinA (OBoNT) and complexing protein-free incobotulinumtoxinA (IBoNT) was recently developed.

Long-term efficacy and safety of a new botulinum toxin type A preparation in mouse gastrocnemius muscle

A new type A botulinum toxin (BoNT/A) preparation, JTM201 (NCBI chromosomal DNA ID: CP046450), has been developed, which comprises 900-kDa complexed toxin purified from Clostridium botulinum (strain: NCTC13319), but its safety and efficacy have not yet been evaluated. The purpose of this study was to evaluate the long-term efficacy and safety of JTM201 at different concentrations in comparison to another commercially available BoNT/A product, Botox® (onabotulinumtoxin A, ONA), using a mouse model. The LD₅₀ of JTM201 was similar to that of ONA, but the intrinsic activity of JTM201 was higher than that of ONA. Functional recovery of the nerves and muscles in SKH-1 mice after administration of the two BoNT/A preparations (JTM201 and ONA) to the right gastrocnemius muscle was observed over 24 weeks. In addition, JTM201 did not induce any skin or muscle inflammatory response in 24 weeks. Paralysis induced by neurotransmitter blockade after JTM201 administration was comparable to that of ONA treatment. Both muscle weight and volume decreased in a concentration-dependent manner following JTM201 or ONA toxin injection until week 4. Reduced muscle fiber size due to atrophy and consequent fibrosis were detected following injection of JTM201 or ONA. Moreover, we assessed the extent of diffusion of JTM201 or ONA to the tibialis anterior and quadriceps femoris muscles, demonstrating limited diffusion to off-target muscles. In conclusion, JTM201 demonstrated long-term efficacy and safety equivalent to those of ONA based on compound muscle action potential, muscle volume, and histology analyses. These data suggest that JTM201 is a new BoNT/A formulation with safety and efficacy comparable to those of ONA.

Botulinum Toxin as a Biological Warfare Agent: Poisoning, Diagnosis and Countermeasures

Botulinum toxin is a neurotoxin produced by Clostridium botulinum and some other relative species. It causes a lethal disease called botulism. It can enter the body via infections by Clostridium (e.g. wound and children botulism) or by direct contact with the toxin or eating contaminated food (food-borne botulism). Botulinum toxin is also considered as a relevant biological warfare agent with an expected high number of causalities when misused for bioterrorist or military purposes. The current paper surveys the actual knowledge about botulinum toxin pathogenesis, the manifestation of poisoning, and current trends in diagnostics and therapeutics. Relevant and recent literature is summarized in this paper.

Neurotoxin Impurities: A Review of Threats to Efficacy

Recently launched esthetic botulinum toxin serotype A (BoNT/A) products include Nabota/Jeuveau, Meditoxin/Neuronox, and Botulax, which contain nontoxic accessory proteins and excipients. Clinical evidence supporting these formulations, including their purity and potential immunogenicity or their link to treatment failures, is limited. Any nonhuman protein, including nontoxin accessory proteins, can initiate immune reactions, especially if administered repeatedly, yet the issue of BoNT/A-induced immunogenicity is widely contested. However, there have been multiple reports of treatment failures and observations of BoNT/A-induced neutralizing antibodies. Compared with the purified formulation in Xeomin, these recently launched toxins contain higher total neurotoxin quantities, much of which is inactive and exposes patients to potentially immunogenic nontoxin proteins or inactive neurotoxins that increase their risk of developing treatment failure. Well-established products [especially abobotulinumtoxinA (Dysport), onabotulinumtoxinA (Botox) and Xeomin] are accompanied by comprehensive and long-ranging clinical evidence on safety and efficacy in esthetic facial indications, which still remains undisclosed for many of the recently introduced toxins. Clinicians need this information as patients will require repeated BoNT treatments and may be unnecessarily but cumulatively exposed to potential immunogens. To underscore the need for caution and further evidence, we review some of the issues surrounding BoNT/A-induced immunogenicity and antibody-induced treatment failures and argue that using highly purified toxins that do not negatively impact patient outcomes is a prudent clinical decision.

Protective Effect of Botulinum Toxin Type A Against Atopic Dermatitis-Like Skin Lesions in NC/Nga Mice

BACKGROUND

Botulinum neurotoxin (BTX) A possesses various biological activities, including anti-inflammatory and antipruritic actions. Human and animal studies have shown that BTX is effective in treating histamine-induced itch, lichen simplex chronicus, psoriasis, rosacea, allergic rhinitis, and scar prevention. However, its effect on atopic dermatitis (AD) has not been studied yet.

OBJECTIVE

To examine the effect of BTX on AD using a mouse model. The primary outcome was skin thickness and transepidermal water loss (TEWL), and the secondary outcome was the alteration in skin severity scores, histological, and laboratory test results.

METHODS

Forty-two NC/Nga mice (a mouse model for AD) were allocated into 6 groups (the untreated, 2-Chloro-1,3,5-trinitrobenzene [TNCB] alone, TNCB + BTX 30 U/kg, TNCB + BTX 60 U/kg, TNCB + vehicle [0.9% saline], TNCB + 0.03% tacrolimus). Those of the BTX group received intradermal injections of BTX on the rostral back once on the day of TNCB sensitization. The effect of BTX in TNCB-treated NC/Nga mice was assessed by measuring skin thickness, TEWL (primary outcome), the skin severity scores, histological changes of test skin including mast cell count, interleukin (IL)-4 mRNA and protein expression, and total serum IgE (secondary outcome).

RESULTS

A single intradermal injection of BTX significantly suppressed skin thickness and TEWL in the TNCB-applied skin. The clinical severity scores, acanthosis and mast cell infiltration, were less in the BTX groups. BTX injection also inhibited TNCB-induced increase in IL-4 mRNA and protein expression in mice, but its effect on serum IgE level was not significant.

CONCLUSION

The preliminary results suggest that BTX may be a novel approach to the prevention and supplemental treatment of acute AD lesions.

Lower facial remodeling with botulinum toxin type A for the treatment of masseter hypertrophy

BACKGROUND

Masseter hypertrophy has been treated with botulinum toxin injections because of esthetic complaints especially in Asians.

OBJECTIVES

The goal of the present study was to evaluate the efficacy of abobotulin toxin use in masseter hipertrophy treatment in Brazilians.

METHODS

Ten Brazilian female patients with masseter hypertrophy were subjected to injections of 90U of abobotulinum toxin A applied on each side respecting the safety zone stabilished in literature and were followed up for 24 weeks.

RESULTS

When analyzing the coefficients between measures of middle and lower third of the face obtained from standardized photographs, an increase was observed, with statistical significance at 2 weeks (p=0.005) and 12 weeks (p=0.001). The progression of lower third reduction was 3.94%, 5.26%, 11.99%, and 5.47% (2, 4, 12, and 24 weeks respectively). All patients showed improvement in bruxism after treatment. Observed adverse effects were masticatory fatigue, smile limitation, and smile asymmetry.

CONCLUSION

The use of abobotulinum toxin A for masseter hypertrophy is effective in Brazilians and reached its maximum effect of facial thinning at 12 weeks. Smile limitation had a higher incidence compared to that reported in the literature and may result from risorius muscle blockage caused by toxin dissemination. Despite its side effects, 80% of the patients would like to repeat the treatment.