Treatment of Chronic Migraine with Focus on Botulinum Neurotoxins

Cellular and molecular mechanisms involved in the analgesic effects of botulinum neurotoxin: A literature review

Botulinum neurotoxins (BoNTs), derived from Clostridium botulinum, have been employed to treat a range of central and peripheral neurological disease. Some studies indicate that BoNT may be beneficial for pain conditions as well. It has been hypothesized that BoNTs may exert their analgesic effects by preventing the release of pain-related neurotransmitters and neuroinflammatory agents from sensory nerve endings, suppressing glial activation, and inhibiting the transmission of pain-related receptors to the neuronal cell membrane. In addition, there is evidence to suggest that the central analgesic effects of BoNTs are mediated through their retrograde axonal transport. The purpose of this review is to summarize the experimental evidence of the analgesic functions of BoNTs and discuss the cellular and molecular mechanisms by which they can act on pain conditions. Most of the studies reviewed in this article were conducted using BoNT/A. The PubMed database was searched from 1995 to December 2022 to identify relevant literature.

Transcranial Magnetic Stimulation as a Therapy for Migraine: An Overview of Systematic Reviews

Introduction

This overview of systematic reviews (SRs) systematically collected, evaluated, and combined the evidence for migraine treatment with transcranial magnetic stimulation (TMS).

Methods

We conducted a systematic literature search in various databases, such as PubMed, The Cochrane Library, Web of Science, Embase, the China National Knowledge Infrastructure, Wanfang, VIP, and China Biomedical Literature. Two reviewers independently assessed the methodological quality, risk of bias, reporting quality, and strength of evidence of the included studies using AMSTAR-2, ROBIS, the PRISMA checklist, and the GRADE system.

Results

We performed an overview of 7 relevant SRs, of which 4 were of moderate quality and 3 were of low quality according to AMSTAR 2. All SRs had low risk of bias in Phase 1 (Assessing relevance), Domain 1 (Study eligibility criteria), and Domain 4 (Synthesis and findings) as evaluated by ROBIS. In Domain 2 (Identification and selection of studies), 4 SRs (57.1%) had low risk of bias, while in Domain 3 (data collection and study appraisal) and Risk of Bias in the Review Phase 3, 4 SRs (57.1%) had low risk of bias. The PRISMA reporting standards were generally comprehensive, but some limitations were observed in the assessments, pooled results, evidence reliability, registration and protocols, and funding sources. The GRADE levels ranged from moderate to low, with 10 outcomes of moderate quality and 6 outcomes of low quality. The main reason for the low quality of evidence was the small sample size and high heterogeneity of the available studies.

Conclusion

TMS may improve migraine severity and frequency, but the evidence is limited due to methodological flaws and heterogeneity. Future studies should standardize use, assess side effects, and compare with other treatments.

A Qualitative Study to Explore Patient Perspectives of Prophylactic Treatment with OnabotulinumtoxinA for Chronic Migraine

INTRODUCTION

OnabotulinumtoxinA (OBT-A) is one of the most studied prophylactic treatments for chronic migraine. Large clinical trials, and now real-world studies, continue to provide evidence to support the use of OBT-A as an effective treatment to manage chronic migraine. The objective of this study was to explore patient experience and perception of prophylactic treatment with OBT-A for chronic migraine.

METHODS

Data were collected using semi-structured interviews using open-ended questions to uncover rich descriptive data on patient experiences. Interviews were transcribed and analysed using NVivo data analysis software to code and identify themes across the dataset. Three patient groups were included in the analysis: (1) patients who were receiving continued OBT-A treatment; (2) patients who discontinued OBT-A treatment; (3) patients who were recommended for OBT-A treatment but did not proceed.

RESULTS

For patients who received at least one OBT-A treatment, four main themes emerged, which described patients' expectations, experiences, and feelings towards their treatment decisions. Two main themes emerged that were common to patients, who had discontinued their treatment and those, who were recommended for OBT-A treatment but did not proceed, which were identified as potential barriers to initiate or continue prophylactic treatment with OBT-A.

CONCLUSION

Understanding patients' perspective is an important part of clinical practice and may impact on decision-making. Qualitative data can provide a more holistic view of patient care and treatment insights that may not be evaluated during a clinical trial. This study revealed potential barriers to treatment that can inform future policy and practice.

Long term outcome for onabotulinumtoxinA (Botox) therapy in chronic migraine: A 2-year prospective follow-up audit of patients attending the Hull (UK) migraine clinic

Objective:

The objective of this prospective audit was to determine the long term outcome of patients diagnosed with chronic migraine who were treated with onabotulinumtoxinA for the prevention of chronic migraine.

Background:

While long term and real-world studies have confirmed the safety and efficacy of onabotulinumtoxinA in CM, there remains limited information from large patient numbers on the number of cycles and duration of onabotulinumtoxinA needed to successfully convert chronic migraine to episodic migraine, development of resistance to treatment and sustainability of response after stopping treatment.

Methods:

A total of 655 adult patients diagnosed with chronic migraine who received onabotulinumtoxinA at the Hull Migraine Clinic were followed up prospectively for a minimum of 2 years. OnabotulinumtoxinA was delivered as per the PREEMPT study protocol and patients were asked to keep a headache diary for at least 30 days prior to and continuously after receiving onabotulinumtoxinA. The primary outcome assessed in this prospective real-world audit was either the number of patients who achieved a ≥50% reduction in headache days or migraine days or an increment in crystal clear days twice that of baseline in a 30-day period. Patients were also assessed for analgesic medication overuse.

Results:

Treatment data were available for 655 patients who commenced treatment between July 2010 and October 2016 and followed for at least 2 years (24–70 months), with the last follow-up taking place in September 2018. Of the 655 patients, 380 patients responded to treatment after two cycles and went on to receive the third cycle. Of these, 152 patients were still on active treatment at 2 years. A further 61 patients had relapsed and were on treatment at 2 years. Of the 228 patients who stopped treatment, 112 were successfully converted to episodic migraine and showed a sustained response, 28 reverted to chronic migraine after the initial response despite continuing treatment (developed resistance), 14 were lost to follow up and 61 patients after achieving remission relapsed after a mean of 9 months (range 4–24 months) and recommenced treatment with onabotulinumtoxinA.

Conclusion:

After a minimum of 2 years, 29.4% of patients with chronic migraine who initially responded to treatment were successfully converted to episodic migraine and maintained a sustained response. Forty percent of the initial cohort of responders continued therapy with onabotulinumtoxinA to manage their chronic migraine.

Intramuscular BoNT/A injections cause an inflammatory response in the muscle tissue of rats

Objectives

The purpose of the present study was to investigate whether intramuscular BoNT/A injections cause an systemic inflammatory response and a local inflammatory response in the muscle tissue.

Methods

Thirty-two male Sprague Dawley rats treated with BoNT/A (i.m., 1IU) were divided in four groups, depending on the time of BoNT/A injection (2 days before, 1, 2, and 4 weeks before the experiment). Bio-Plex Pro Rat Cytokine 23-plex Multiplex Assay (Bio-Rad, USA).

Results

Systemic inflammation: 17 cytokines (IL1-α ( p = 0.005), IL-1β ( p = 0.01), IL-2 ( p = 0.04), IL-4 ( p = 0.03), IL-6 ( p = 0.03), IL-10 ( p = 0.02), IL12(p70) ( p = 0.03), IL-13 ( p = 0.04), IL-17 ( p = 0.03), GM-CSF ( p = 0.03), INF-γ ( p = 0.03), MIP-1α ( p = 0.03), MIP-3α ( p = 0.04), RANTES ( p = 0.001), TNF-α ( p = 0.04), vascular endothelial growth factor ( p = 0.03), and MCP-1 ( p = 0.02)) showed significantly higher expression levels 2 days after intramuscular BoNT/A injections compared to other time points (1, 2, and 4 weeks). Local inflammation: 12 cytokines (IL-1β ( p = 0.02), IL-6 ( p = 0.002), IL-10 ( p = 0.02), IL-13 ( p = 0.04), IL-17 ( p = 0.02), TNF-α ( p = 0.001), GM-CSF ( p = 0.01), M-CSF ( p = 0.04), MIP-1α ( p = 0.04), MIP-3α ( p = 0.002), RANTES ( p = 0.02), and MCP-1( p = 0.004)) showed higher expression levels 2 and/or 4 weeks after intramuscular BoNT/A injections compared to the other time points (2 days and 1 week).

Conclusion

Intramuscular BoNT/A injections result in a rapid systemic inflammatory response that only lasts a couple of days. At the same time, intramuscular BoNT/A injections cause an inflammatory response locally in the muscle with significantly higher cytokine levels 2 and/or 4 weeks after injections.

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.

The Therapeutic Impact of New Migraine Discoveries

BACKGROUND

Migraine is one of the most disabling neurological conditions and associated with high socio-economic costs. Though certain aspects of the pathomechanism of migraine are still incompletely understood, the leading hypothesis implicates the role of the activation of the trigeminovascular system. Triptans are considered to be the current gold standard therapy for migraine attacks; however, their use in clinical practice is limited. Prophylactic treatment includes non-specific approaches for migraine prevention. All these support the need for future studies in order to develop innovative anti-migraine drugs.

OBJECTIVE

The present study is a review of the current literature regarding new therapeutic lines in migraine research.

METHODS

A systematic literature search in the database of PUBMED was conducted concerning therapeutic strategies in a migraine published until July 2017.

RESULTS

Ongoing clinical trials with 5-HT1F receptor agonists and glutamate receptor antagonists offer promising new aspects for acute migraine treatment. Monoclonal antibodies against CGRP and the CGRP receptor are revolutionary in preventive treatment; however, further long-term studies are needed to test their tolerability. Preclinical studies show positive results with PACAP- and kynurenic acid-related treatments. Other promising therapeutic strategies (such as those targeting TRPV1, substance P, NOS, or orexin) have failed to show efficacy in clinical trials.

CONCLUSION

Due to their side-effects, current therapeutic approaches are not suitable for all migraine patients. Especially frequent episodic and chronic migraine represents a therapeutic challenge for researchers. Clinical and preclinical studies are needed to untangle the pathophysiology of migraine in order to develop new and migraine-specific therapies.

A Critical Review of Botulinum Toxin Type A in the Prophylactic Treatment of Chronic Migraine in Adults

BACKGROUND

Migraine is a severe, disabling condition, ranked by World Health Organization as the sixth highest cause of disability worldwide. It greatly affects patients' quality of life, functionality, and physical and mental health. The financial burden of migraine on the UK economy is conservatively estimated at £3.42 billion per year.

OBJECTIVES

The authors sought to perform an evidence-based literature review of the safety and efficacy of botulinum toxin type A (onaBoNTA) in the prophylactic treatment of adult patients suffering with chronic migraine (CM) compared to placebo. After the best evidence is identified, it will be utilized to formulate a protocol for doctors managing CM in their aesthetic clinic.

METHODS

A comprehensive search of the current literature on the topic was performed by H.M. using Pubmed MEDLINE electronic database on March 1, 2018. All articles up to and inclusive of this date were included. Articles were limited to human studies and those in the English language. In vitro and animal studies were excluded.

RESULTS

A total of 260 articles were identified. Of these, the excellent-quality, high-strength (level 1A) trials were short-listed to answer the research question.

CONCLUSIONS

There is high-quality, level 1A evidence to support onaBoNTA treatment in adults with CM is well tolerated and considered safe. However, it is associated with increased risk of adverse events and still some uncertainty exists associated with the degree onaBoNTA improves outcome measures compared to placebo. These data have been used to formulate The London Aesthetic Migraine Protocol (LAMP) to provide safe, evidence-based guidance for appropriately trained and experienced aesthetic practitioners to manage CM in their aesthetic clinics.

LEVEL OF EVIDENCE: 1

[Real-world migraine burden: clinical and economic aspects]

AIM

To evaluate the rationale for different approaches to preventive chronic migraine (CM) treatment by comparing clinical outcomes and financial burden of the disease in the real-world practice.

MATERIAL AND METHODS

Sixty-six patients with CM were enrolled at the Alexander Vein Headache Clinic (60 women and 6 men, aged 28-51). All patients were divided into 3 groups: group 1 (n=22) received oral preventative treatment with topiramate, up to 100 mg daily, for three months; group 2 (n=20) received 12 acupuncture sessions (3 sessions a week); group 3 (n=24) received 155-195 units of botulinum toxin type A (botox, BTA). The follow-up period in all groups was 3 months. Efficacy was evaluated by clinical examination, the Headache Impact Test (HIT-6) and questionnaires to assess subjective patient satisfaction and treatment tolerability.

RESULTS

BTA demonstrated the highest efficacy in this study. Compared to the oral preventative treatment and acupuncture, BTA reduced the frequency of headache faster and more significantly facilitating CM transformation into episodic migraine (headache frequency was 16.1±0.1; 18.0±0.02; and 13.9±0.3 in groups 1, 2 and 3, respectively, after one month of treatment). BTA also improved the quality of life faster and more significantly and was better tolerated (good - 51%, 75% and 85% in groups 1, 2 and 3, respectively; satisfactory - 35%, 25% and 15% in groups 1, 2 and 3, respectively; bad 14% in the oral prevention group). In the BTA group, the majority of patients demonstrated earlier treatment satisfaction. Despite higher (compared to topiramate) direct costs in the BTA group (RUB 29 931.51 and RUB 32 085.87, respectively), the predicted cost of a headache-free day was the smallest and totaled RUB 652.15 (compared to RUB 692.86 and RUB 1017.60 in the topiramate and acupuncture groups, respectively).

CONCLUSION

The data on the efficacy and costs of different CM prevention strategies would facilitate optimal treatment choice for neurologists and patients.

A SNAP-25 cleaving chimera of botulinum neurotoxin /A and /E prevents TNFα-induced elevation of the activities of native TRP channels on early postnatal rat dorsal root ganglion neurons

Transient receptor potential (TRP) vallinoid 1 (TRPV1) and ankyrin 1 (TRPA1) are two transducing channels expressed on peripheral sensory nerves involved in pain sensation. Upregulation of their expression, stimulated by inflammatory cytokines and growth factors in animal pain models, correlate with the induction of nociceptive hyper-sensitivity. Herein, we firstly demonstrate by immuno-cytochemical labelling that TNFα augments the surface content of these channels on rat cultured dorsal root ganglion (DRG) neurons which, in turn, enhances the electrophysiological and functional responses of the latter to their specific agonists. A molecular basis underlying this TNFα-dependent enhancement was unveiled by pre-treating DRGs with a recently-published chimeric protein, consisting of the protease light chain (LC) of botulinum neurotoxin (BoNT) serotype E fused to full-length BoNT/A (LC/E-BoNT/A). This cleaves synaptosomal-associated protein of Mr 25k (SNAP-25) and reported previously to exhibit anti-nociceptive activity in a rat model of neuropathic pain. Low pM concentrations of this chimera were found to prevent the TNFα-stimulated delivery of TRPV1/A1 to the neuronal plasmalemma and, accordingly, decreased their incremental functional activities relative to those of control cells, an effect accompanied by SNAP-25 cleavage. Advantageously, LC/E-BoNT/A did not reduce the basal surface contents of the two channels or their pharmacological responses. Thus, use of multiple complementary methodologies provides evidence that LC/E-BoNT/A abolishes the TNFα-dependent augmented, but not resting, surface trafficking of TRPV1/A1. As TNFα is known to induce nociceptive hyper-sensitivity in vivo, our observed inhibition by LC/E-BoNT/A of its action in vitro could contribute to its potential alleviation of pain.

Headache and Its Management in Patients With Multiple Sclerosis

PURPOSE OF REVIEW

The purpose of this review was to discuss the prevalence, impact, pathophysiology, and treatment of headaches (H/As) in patients with multiple sclerosis (MS).

RECENT FINDINGS

Headaches and multiple sclerosis are more common in women than in men with the ratio of female to male being 3:1. It is not entirely clear if there is a correlation or an incidental comorbidity of two neurological conditions. A review of the literature shows a variable prevalence of H/As in MS patients. Using the International Classification of Headache Disorders (ICHD) criteria, the primary type of H/As, especially migraine, is the most common type seen in patients with MS. One of the theories of the pathophysiologic mechanisms of migraine in MS patients is inflammation leading to demyelinating lesions in the pain-producing centers in the midbrain. Secondary H/As due to MS medications such as interferons are also frequently present. H/As can be a cause for significant comorbidity in patients with MS. The treatment of H/As in patients with MS should be addressed in the same fashion as in the non-MS population, which is a combination of pharmacological and non-pharmacological methods. Preventive medicines for the H/As should be carefully selected because of their side effect profiles. Acute attacks of migraines can be treated with medications such as triptans. Patients with MS who have migraine H/As should be educated about the phenomenon of overuse H/As, keeping headache journals, avoiding stress, and monitoring sleeping habits. The presence of depression in patients with MS and migraine affects quality of life (QOL) and should also be addressed for better outcomes.

Long-term study of the efficacy and safety of OnabotulinumtoxinA for the prevention of chronic migraine: COMPEL study

BACKGROUND

OnabotulinumtoxinA is approved for the prevention of headache in those with chronic migraine (CM); however, more clinical data on the risk-benefit profile for treatment beyond one year is desirable.

METHODS

The Chronic Migraine OnabotulinuMtoxinA Prolonged Efficacy open Label (COMPEL) Study ( ClinicalTrials.gov , NCT01516892) is an international, multicenter, open-label long-term prospective study. Adults with CM received 155 U of onabotulinumtoxinA (31 sites in a fixed-site, fixed-dose paradigm across 7 head/neck muscles) every 12 weeks (±7 days) for 9 treatment cycles (108 weeks). The primary outcome was headache day reductions at 108 weeks; secondary outcomes were headache day reductions at 60 weeks and change in the 6-item Headache Impact Test (HIT-6) score. Safety and tolerability were assessed by reviewing the frequency and nature of adverse events (AEs). AEs were determined at each visit through patient self-report, general non-directed and, for specific AEs, directed questioning, and physical examination. Subgroup analyses for safety and efficacy included, but were not limited to, patients with/without concomitant oral preventive treatment and acute medication overuse at baseline.

RESULTS

Enrolled patients (N = 716) were 18-73 years old and most were female (n = 607, 84.8%). At baseline, patients reported an average 22.0 (SD = 4.8) headache days per month. 52.1% of patients (n = 373) completed the study. By 60 and 108 weeks, a significant reduction in headache days (- 9.2 days and - 10.7 days, respectively, P < 0.0001) was observed. Significant improvements (P < 0.0001) in HIT-6 scores (- 7.1 point change at week 108) were also demonstrated. 131 patients (18.3%) reported ≥1 treatment-emergent adverse events; most frequently reported was neck pain (n = 29, 4.1%). One patient reported a serious treatment-related adverse event (rash). No deaths were reported.

CONCLUSIONS

The COMPEL Study provides additional clinical evidence for the consistency of the efficacy and for the long-term safety and tolerability of onabotulinumtoxinA for the prevention of headache in those with CM who have been treated with onabotulinumtoxinA every 12 weeks over 2 years (9 treatments) with the fixed-site, fixed-dose injection paradigm.

TRIAL REGISTRATION

Trial registration number: NCT01516892 . Name of registry: clinicaltrials.gov . Date of registration: January 20 2012. Date of enrollment of first patient: December 2011.

Injection of high dose botulinum-toxin A leads to impaired skeletal muscle function and damage of the fibrilar and non-fibrilar structures

Botulinum-toxin A (BoNT/A) is used for a wide range of conditions. Intramuscular administration of BoNT/A inhibits the release of acetylcholine at the neuromuscular junction from presynaptic motor neurons causing muscle-paralysis. The aim of the present study was to investigate the effect of high dose intramuscular BoNT/A injections (6 UI = 60 pg) on muscle tissue. The gait pattern of the rats was significantly affected 3 weeks after BoNT/A injection. The ankle joint rotated externally, the rats became flat footed, and the stride length decreased after BoNT/A injection. Additionally, there was clear evidence of microstructural changes on the tissue level by as evidenced by 3D imaging of the muscles by Synchrotron Radiation X-ray Tomographic Microscopy (SRXTM). Both the fibrillar and the non-fibrillar tissues were affected. The volume fraction of fibrillary tissue was reduced significantly and the non-fibrillar tissue increased. This was accompanied by a loss of the linear structure of the muscle tissue. Furthermore, gene expression analysis showed a significant upregulation of COL1A1, MMP-2, TGF-b1, IL-6, MHCIIA and MHCIIx in the BoNT/A injected leg, while MHVIIB was significantly downregulated.

IN CONCLUSION

The present study reveals that high dose intramuscular BoNT/A injections cause microstructural damage of the muscle tissue, which contributes to impaired gait.

Effects of onabotulinumtoxinA treatment on efficacy, depression, anxiety, and disability in Turkish patients with chronic migraine

Chronic migraine causes a serious labour loss and disability in the society and increases the risk of depression and anxiety by negatively affecting the quality of life. The purpose of this study was to investigate the effects of onabotulinumtoxinA (BoNT-A) treatment on efficacy before and after treatment in our cases with chronic migraine as well as on depression, anxiety and disability caused by migraine. According to the International Headache Classification (ICHD-III beta version), 60 adult patients who were diagnosed with chronic migraine were included in the study. A total of 155 IU BoNT-A treatment from 31 regions was administered in accordance with the protocol of PREEMPT study. Information about the characteristics of patients' headaches, background and family history, drugs they used was recorded. At the baseline and in the first and third month after the BoNT-A injection, VAS scores, the number of both headache days and attacks, the headache duration, the frequency of application to emergency services and the intake of both analgesics and triptans during attacks were evaluated. MIDAS, BDI and BAI were evaluated at the baseline and in the third month after the BoNT-A injection. BoNT-A injection provided a significant decrease in the number of days and severity of headaches, MIDAS disability scores and psychiatric complaints in cases with chronic migraine who did not respond to prophylactic treatments in the third month of the treatment.