Therapeutically relevant features of botulinum toxin drugs

Embracing the Versatility of Botulinum Neurotoxins in Conventional and New Therapeutic Applications

Botulinum neurotoxins (BoNTs) have been used for almost half a century in the treatment of excessive muscle contractility. BoNTs are routinely used to treat movement disorders such as cervical dystonia, spastic conditions, blepharospasm, and hyperhidrosis, as well as for cosmetic purposes. In addition to the conventional indications, the use of BoNTs to reduce pain has gained increased recognition, giving rise to an increasing number of indications in disorders associated with chronic pain. Furthermore, BoNT-derived formulations are benefiting a much wider range of patients suffering from overactive bladder, erectile dysfunction, arthropathy, neuropathic pain, and cancer. BoNTs are categorised into seven toxinotypes, two of which are in clinical use, and each toxinotype is divided into multiple subtypes. With the development of bioinformatic tools, new BoNT-like toxins have been identified in non-Clostridial organisms. In addition to the expanding indications of existing formulations, the rich variety of toxinotypes or subtypes in the wild-type BoNTs associated with new BoNT-like toxins expand the BoNT superfamily, forming the basis on which to develop new BoNT-based therapeutics as well as research tools. An overview of the diversity of the BoNT family along with their conventional therapeutic uses is presented in this review followed by the engineering and formulation opportunities opening avenues in therapy.

Ultrasonographic observation of the masseter muscle after injection of different botulinum toxin type A

BACKGROUND

Botulinum toxin type A (BoNT-A) injection is a popular cosmetic procedure in East Asian countries, and there are multiple types of toxins on the market. Whether different toxin types induce different changes in the masseter has not been studied.

OBJECTIVE

We aimed to investigate and compare the changes induced by injection of different types of BoNT-A in the masseter.

METHODS

Upon retrospective review of clinical records and routine ultrasound examination results of patients who underwent BoNT-A injection, four groups were set for comparison: unapproved toxin, OnabotulinumtoxinA, LanbotulinumtoxinA, and non-injected. Clinical records and ultrasound images were collected. Ultrasound images were taken in both horizontal and coronal planes. Elasticity of the masseter muscle was also investigated by measuring the surface wave speed.

RESULTS

A total of 24 patients were included (six patients per group). All patients were young females. For the non-injected group, the deep inferior tendon was clear and the muscle bundles were arranged, with little fibrous content. Patients who received unapproved toxin injection showed highly disarranged muscle and fiber bundles, with much fiber content present. The changes in OnabotulinumtoxinA and LanbotulinumtoxinA groups were in between those in the non-injected and unapproved toxin groups. Muscle rigidity was the highest in the unapproved toxin group, and generally higher in injected groups compared with the non-injected group.

CONCLUSION

Different types of BoNT-A may induce different changes in the masseter.

Hengli® Chinese Botulinum Toxin Type A for Treatment of Patients With Overactive Bladder: A Multicenter, Prospective, Randomized, Double-Blind, Placebo-Controlled Trial

Objective: To evaluate the efficacy and safety of Hengli^® Chinese botulinum toxin type A (BTX-A; 100 U) in Chinese patients with overactive bladder.

Methods: This study was a multicenter, randomized, double-blind, placebo-controlled trial in Chinese patients who were inadequately managed with anticholinergic medications. Eligible patients were randomized 2:1 to receive intradetrusor injections of Hengli^® BTX-A (n = 144) or placebo (n = 72). The primary endpoint was the change in the number of daily micturition episodes at week 6 from baseline. The secondary efficacy endpoints included the average frequency of urgency and urinary incontinence (UI) episodes per day, urgency score, average micturition volume per day, OABSS, and QoL score.

Results: In the Hengli^® BTX-A group, there was a significantly greater reduction in the average number of micturition episodes per 24 h compared with the placebo group (3.28 vs. 1.43; p = 0.003). Moreover, there was a significantly greater improvement in the daily number of urgency episodes, micturition volume and OABSS score. An increased post-void residual urine volume, dysuria, and urinary tract infection represented adverse events (AEs) in the Hengli^® BTX-A group. Most AEs were mild or moderate in severity. One patient in the BTX-A group initiated clean intermittent catheterization (CIC) during treatment.

Conclusion: Hengli^® BTX-A treatment was well-tolerated and resulted in significant improvements in OAB symptoms among Chinese patients inadequately managed by anticholinergics.

Clinical Trial Registration:http://www.chinadrugtrials.org.cn/clinicaltrials.prosearch.dhtml, Identifier: CTR20131190.

Aesthetic Treatments in Cancer Patients

Cancer patients are experiencing an increase in overall survival as a consequence of earlier diagnosis and newer effective anticancer therapies. However, cancer survivors often face long-term consequences from their original cancer diagnosis and long-term sequelae of anticancer treatment. Maintaining patients' quality of life is of paramount importance and this can be accomplished by a multidisciplinary treatment approach, including aesthetic treatments to improve patients' body image and positively impact their quality of life. In this perspective, we will discuss the importance of aesthetic treatments in cancer patients. In addition, we will summarise the data available regarding the use of several aesthetic treatments such as fillers, botulinum toxin and laser use in cancer patients, their safety, their efficacy, and the specific precautions that need to be implemented in this particular subset of cancer patients.

Management of excessive gingival display using botulinum toxin type A: a descriptive study

Botulinum toxin is a protease used by the bacterium Clostridium botulinum that causes chemical denervation of skeletal muscles, producing a temporary weakening of muscle activity. Despite having a transitory effect, the application of botulinum toxin has been identified as an alternative for correcting an excessive gingival display (EGD). However, studies evaluating the maintenance of long-term results of botulinum toxin remain scarce. This study aimed to evaluate the effectiveness and duration of botulinum toxin type A in the treatment of anterior EGD. Botulinum toxin Type A was applied to 15 patients with EGD. The measurement was performed in triplicate, using a Castro Viejo dry point compass, between the central cervical portion of the upper lateral incisors to the lower portion of the upper lip, bilaterally. The measurements were performed before the application of the toxin and repeated on days 7, 14, 90, 120, and 180 after the procedure. The data were analyzed using repeated-measures ANOVA, followed by a Bonferroni. There was a statistically significant reduction between the measurements performed on the Baseline and seven days after the application of the botulinum toxin. After 180 days, approximately one-quarter of the patients in the sample did not presented EGD. Mild adverse effects were reported by 46.7% of the patients. The use of botulinum toxin type A was effective to treat EGD. After 180 days, it was still possible to observe a significant effect compared to the initial gingival exposure.

Image-guided botulinum toxin injection in the lateral abdominal wall prior to abdominal wall reconstruction surgery: review of techniques and results

Ventral hernias represent the most common complication after abdominal surgery. Loss of domain and/or large ventral hernias in patients are especially challenging for surgeons to manage, but preoperative image-guided botulinum toxin injection has emerged as an effective adjunct to abdominal wall surgery. Loss of domain is caused by chronic muscle retraction of the lateral abdominal wall and leads to an irreducible protrusion of abdominal viscera into the hernia sac. Botulinum toxin can be used in the oblique muscles as a chemical component relaxation technique to aid abdominal wall reconstruction. Intramuscular botulinum toxin injection causes functional denervation by blocking neurotransmitter acetylcholine release resulting in flaccid paralysis and elongation of lateral abdominal wall muscles, increasing the rate of fascial closure during abdominal wall reconstruction, and decreasing recurrence rates. In total, 200-300 units of onabotulinumtoxinA (Botox®) or 500 units of abobotulinumtoxinA (Dypsort®) in a 2:1 dilution with normal saline is most commonly used. Botulinum toxin can be injected with ultrasonographic, EMG, or CT guidance. Injection should be performed at least 2 weeks prior to abdominal wall reconstruction, for maximal effect during surgery. At minimum, botulinum toxin should be injected into the external and internal oblique muscles at three separate sites bilaterally for a total of six injections. Although botulinum toxin use for abdominal wall reconstruction is currently not indicated by the Food and Drug Administration, it is safe with only minor complications reported in literature.

Intragastric Botulinum Toxin A Injection Is an Effective Obesity Therapy for Patients with BMI > 40 kg/m2: a Systematic Review and Meta-analysis

We conducted a systematic review and meta-analysis to assess the efficacy of intragastric BTA injection in patients with obesity and morbid obesity. Five RCTs were identified. Intragastric BTA injection was no superior to saline in absolute weight loss or BMI change, but significantly lengthened the gastric emptying time (MD, 15.57; 95% CI, 8.75 to 22.38). In meta-regression analysis, the absolute weight loss was lower in the patients with high baseline BMI. In subgroup analysis, the use of BTA in absolute weight loss was significantly lower among the patients with baseline BMI more than 40 kg/m² (MD, - 5.31; 95% CI, - 6.17 to - 4.45). The benefit of intragastric BTA injection in reduction of absolute weight was observed in patients with baseline BMI more than 40 kg/m².

The Use of Botulinum Toxin A in the Management of Trigeminal Neuralgia: a Systematic Literature Review

OBJECTIVES

The purpose of this article is to systematically review the use, efficacy, differences between botulinum toxin type A doses and side effects of botulinum toxin type A therapy in patients with trigeminal neuralgia.

MATERIAL AND METHODS

The search for the performed reviews was done in PubMed and Cochrane library in English language from January 2010 up to February 2020. Inclusion criteria: full-text studies in English language, in which visual assessment scale (VAS) was present, in which patients with trigeminal neuralgia (TN) were participated and the comparison between botulinum toxin type A (BT-A) and saline was done.

RESULTS

The review included 4 randomized, double-blind, placebo-controlled trials with 8 to 12 weeks follow-up to observe changes in VAS and in frequency of TN attacks, differences between dosages of BT-A in therapy and side effects. Mean VAS of BT-A group decreased by approximately 68% and of palcebo group decreased by approximately 21.6% after the therapy. Mean frequency of TN attacks in 3 studies of BT-A group decreased by 85%, while in palcebo by only 15.9%.

CONCLUSIONS

Botulinum toxin type A injection therapy is a safe and effective method in management of trigeminal neuralgia. No differences between dosages of botulinum toxin type A were found. Maximum efficacy was noticed between 6 weeks and 3 months after the procedure. Side effects were mostly facial asymmetry after injection, headaches, haematoma, which disappeared in one week.