Pharmakologische Aspekte therapeutischer Botulinum-Toxin-Präparationen

The Immunology of Botulinum Toxin Therapy: A Brief Summary

Like all proteins foreign to the human body, also botulinum toxin (BT) is antigenic and may stimulate an immune response with formulation of antibodies (BT-AB). Affected patients may no longer respond to BT therapy and various degrees of BT-AB related therapy failure (ABF) may result. We want to review the immunological interactions between BT and BT-AB, the prevalence, the time course and the risk factors for BT-AB formation as they are related to the treatment algorithms, the patient's immune system and to exogenic factors. Special emphasis is placed on various features of the BT drugs including the specific biological activity (SBA) as a predictor of their antigenicity. Quantitative detection of BT-AB by the mouse diaphragm assay will be demonstrated. As ABF may have serious consequences for patients affected, careful risk factor analysis is warranted to reduce them wherever possible.

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.

A comparative, prospective, split-face, blind study of the efficacy of two botulinum toxin type A drugs (Disport® and Xeomin®) used to correct lateral periorbital wrinkles

A prospective- blind- split-face- comparative study with evaluation of clinical efficacy- tolerability- and safety parameters of two botulinum toxin A (BTA) products (the one containing complexing proteins — Disport®- Ipsen- France/ abobotulinumtoxinA and the one free from complexing proteins — Xeomin®- Merz Pharma- Germany/incobotulinumtoxinA) used for correction of lateral periorbital wrinkles (crow's feet) was performed (at that- electromyographic evaluation of changes in functions of the orbicular muscle of eye was performed for the first time). Materials and Methods. Single injections of both BTA products with equal dose ratio of 3:1 (27 IU Disport® and 9 IU Xeomin®) were performed simultaneously to the right and left side half of the face (orbicular muscles of eye)- respectively- to each of 20 volunteers (women at the age of 40.9) with marked and moderate lateral periorbital wrinkles (2—3 degree according to 4-point Facial Wrinkle Scale/FWS). Clinical and electromyographic assessment was performed 2 weeks- 4 and 6 months after injections. Results. The effect of single dosing of Disport® and Xeomin® did not significantly differ at all assessment time points: both for primary efficacy criterion and for all secondary efficacy criteria; as well as for clinical evaluation by the investigator-subjects’ self-evaluation- and dynamics of M-response parameters for the orbicular muscle of eye. Good tolerability and safety were registered. Conclusion. Study results provided convincing evidence that Disport® and Xeomin® used in accordance with the proposed protocol had a comparable effect and duration of the effect on lateral periotbital wrinkles and the orbicular muscle of eye.

Five-year experience with incobotulinumtoxinA (Xeomin(®) ): the first botulinum toxin drug free of complexing proteins

In 2005, incobotulinumtoxinA (Xeomin(®) ), a new botulinum toxin (BT) type A drug without complexing proteins (CPs), became available. This paper reviews the specific features of Xeomin(®) and the experience gathered with it during the last 5 years. Compared with conventional BT drugs, Xeomin(®) 's extended shelf live and its simplified temperature restrictions indicate that CPs are not necessary for BT drug stability. Its reduced molecular size does not translate into diffusion differences, and its potency labelling is identical to that of onabotulinumtoxinA (Botox(®) ). With a reduced content of inactivated botulinum neurotoxin, Xeomin(®) should have reduced antigenicity. Lack of CP's may further reduce antigenicity. Xeomin(®) 's therapeutic efficacy against cervical dystonia, blepharospasm and spasticity has been proven in large randomised, double-blind and placebo-controlled studies leading to registrations in many countries. Additional successful clinical use in axillary hyperhidrosis, hemifacial spasm, re-innervation synkinesias and hypersalivation as well as in dystonia and spasticity in extended doses and throughout extended observation periods has been documented meanwhile. Lack of reported cases of antibody-induced therapy failure (ABF), as to date, support the hypothesis of an improved antigenicity.

Noncosmetic periocular therapeutic applications of botulinum toxin

Botulinum toxin blocks acetylcholine release at the neuromuscular junction. The drug which was initially found to be useful in the treatment of strabismus has been extremely effective in the treatment of variety of conditions, both cosmetic and noncosmetic. Some of the noncosmetic uses of botulinum toxin applications include treatment of spastic facial dystonias, temporary treatment of idiopathic or thyroid dysfunction-induced upper eyelid retraction, suppression of undesired hyperlacrimation, induction of temporary ptosis by chemodenervation in facial paralysis, and correction of lower eyelid spastic entropion. Additional periocular uses include control of synchronic eyelid and extraocular muscle movements after aberrant regeneration of cranial nerve palsies. Cosmetic effects of botulinum toxin were discovered accidentally during treatments of facial dystonias. Some of the emerging nonperiocular application for the drug includes treatment of hyperhidrosis, migraine, tension-type headaches, and paralytic spasticity. Some of the undesired side effects of periocular applications of botulinum toxin inlcude ecchymosis, rash, hematoma, headache, flu-like symptoms, nausea, dizziness, loss of facial expression, lower eyelid laxity, dermatochalasis, ectropion, epiphora, eyebrow and eyelid ptosis, lagophthalmos, keratitis sicca, and diplopia.

Complexing proteins in botulinum toxin type A drugs: a help or a hindrance?

Botulinum toxin type A is a high molecular weight protein complex containing active neurotoxin and complexing proteins, the latter of which, it is believed, protect the neurotoxin when in the gastrointestinal tract, and may facilitate its absorption. Comparisons of conventional botulinum toxin type A drugs that include complexing proteins with the complexing protein-free formulation of Xeomin^® strongly suggest that complexing proteins do not affect diffusion of the active neurotoxin. Studies of Xeomin have also shown that complexing proteins do not enhance product stability in storage. However, complexing proteins may stimulate antibody development against botulinum toxin type A. Numerous observational studies have been published showing that some patients receiving conventional botulinum toxin may develop neutralizing antibodies, leading to antibody-induced therapy failure. Studies have shown that Xeomin is not associated with the development of neutralizing antibodies in animal models or in patients. In conclusion, complexing proteins do not contribute to the stability of botulinum toxin type A drugs and do not contribute to their therapeutic effects, but may be associated with a secondary nonresponse due to the development of neutralizing antibodies.

Botulinum toxin in facial rejuvenation: an update

Since its initial approval by the US Food and Drug Administration (FDA) 20 years ago for the treatment of strabismus, hemifacial spasm, and blepharospasm in adults, botulinum toxin (BTX) has become one of the most frequently requested products in cosmetic rejuvenation around the world. After years of clinical success and consistent safety in the upper face, the use of BTX has expanded and evolved to include increasingly complicated indications. In the hands of adept injectors, the focus has shifted from the treatment of individual dynamic rhytides to shaping, contouring, and sculpting, alone or in combination with other cosmetic procedures, to enhance the aesthetic appearance of the face. Although recent reports have questioned the safety of BTX, 25 years of therapeutic and over 20 years of cosmetic use has demonstrated an impressive record of safety and efficacy when used appropriately by experienced injectors.

Botulinum toxin for pelvic pain in women

Pelvic pain is a common disorder in women, causing significant morbidity. Often the etiology is not clear as it results from a complex interaction between neurologic, musculoskeletal and endocrine systems that is further influenced by behavioral and psychological factors. A comprehensive approach to the problem requires recognition of the multiple organ systems that may be involved. A thorough history and physical examination, followed by selected laboratory and imaging studies, is essential in evaluation of these patients. Medical and surgical management improves or controls the symptoms in the majority of cases, but there remains a group of women who are difficult to treat. Botulinum toxin is a presynaptic neuromuscular blocking agent inducing selective and reversible muscle weakness that lasts several months when injected intramuscularly. It has been shown to be effective in treating pain caused by muscular spasm in conditions other than pelvic pain caused by muscular hypertonicity. Evidence or literature related to treatment of pelvic pain with botulinum toxin is discussed in this review.

Successful treatment of tardive lingual dystonia with botulinum toxin: case report and review of the literature

Tardive dyskinesia (TD) is a dreaded side effect of antipsychotic medication. Recommended treatments for TD may provide reliable improvement but can be, in turn, associated with additional adverse reactions. Recently, several reports have suggested that botulinum toxin A (BTX-A) injection in affected muscles may significantly improve TD. Here, we report a case of severe tongue protrusion dystonia secondary to an antipsychotic medication in a young man. Several approaches including clozapine, amisulpride, aripiprazole, ziprasidone, tiapride and clonazepam failed to improve the symptoms. Injection of 50 U of BTX-A (Dysport, Ipsen, Ettlingen, Germany) into each genioglossal muscle dramatically improved tongue protrusion within few days with a sustained effect. If reasonable precautions are taken, the application seems to be well tolerated with only minor side effects. A review of the literature that is part of this article adverts BTX-A injection as a potential beneficial approach of various kinds of TD.

Botulinum toxin: description of injection techniques and examination of controversies surrounding toxin diffusion

The benefits derived from botulinum toxin (BTX) injections may be negated by unintentional weakness of adjacent uninjected muscles. Such weakness may be the result of inaccurate targeting, or diffusion of BTX to surrounding muscles. Several techniques, using electromyographic, endoscopic or imaging guidance are purported to increase the accuracy of targeting. Diffusion of BTX is thought to be influenced by factors such as dose, concentration, injectate volume, number of injections, site and rate of injection, needle gauge, muscle size, muscular fascia, distance of needle tip from the neuromuscular junction, and protein content of the BTX formulation. This article describes techniques that aim to increase the accuracy of BTX injections and examines the controversies surrounding diffusion of BTX following injection.