Treatment of Chronic Migraine with OnabotulinumtoxinA: Mode of Action, Efficacy and Safety

Emerging drugs for the preventive treatment of migraine: a review of CGRP monoclonal antibodies and gepants trials

INTRODUCTION

Migraine is a leading cause of years lived with disability and preventive strategies represent a mainstay to reduce health-related disability and improve quality of life of migraine patients. Until a few years ago, migraine prevention was based on drugs developed for other clinical indications and relocated in the migraine therapeutic armamentarium, characterized by unfavourable tolerability profiles. The advent of monoclonal antibodies against Calcitonin Gene-Related Peptide (CGRP) and gepants, CGRP receptor antagonists, has been a turning point in migraine prevention owing to advantageous efficacy, safety and tolerability profiles.Nevertheless, while in an ideal scenario a drug characterized by significant greater efficacy and tolerability compared to existing therapeutic strategies should be adopted as a first-line treatment, cost-effectiveness analyses available for monoclonal antibodies against CGRP pathway tend to limit their administration to more severe migraine phenotypes.

AREAS COVERED

The present narrative review aim to provide a critical appraisal of phase II and III CGRP-mAbs and gepants trials to analyse their use in clinical practice.

EXPERT OPINION

Despite monoclonal antibodies against CGRP pathway and gepants can be undoubtedly considered top-of-the-range treatments, there are still issues deserving to be addressed in the coming years as the risk of off-target effects as well as their economic sustainability based on the considerable migraine burden.

A Single-Group Study on the Effect of OnabotulinumtoxinA in Patients with Chronic Migraine Associated with Medication Overuse Headache: Pain Catastrophizing Plays a Role

Pain catastrophizing and cutaneous allodynia are commonly altered in patients with chronic migraine associated with medication overuse headache (CM-MOH) and tend to improve in parallel with clinical improvement. The relation between pain catastrophizing and cutaneous allodynia is poorly understood in patients with CM-MOH receiving OnabotulinumtoxinA therapy. In this single-arm open-label longitudinal observational study, patients with CM-MOH were assigned to structured withdrawal and then administered OnabotulinumtoxinA (5 sessions on a three-month basis, 195 UI per 31 sites). Headache frequency, medication intake, disability, impact, cutaneous allodynia and pain catastrophizing were evaluated with specific questionnaires. In total, 96 patients were enrolled and 79 completed the 12-month follow-up. With the exclusion of cutaneous allodynia and the magnification subscale of the pain catastrophizing questionnaire, all variables showed significant improvement by the sixth month, which was maintained at 12 months. Reduction of pain catastrophizing, and particularly of its helplessness subscale, was a significant predictor of reduction in headache frequency and medication intake. Pain catastrophizing is often implicated in the clinical improvement in patients with CM-MOH receiving behavioral treatments, but, in this study, also showed a role in patients receiving OnabotulinumtoxinA; combining OnabotulinumtoxinA and behavioral treatments specifically addressing pain catastrophizing might further enhance patients' clinical outcome.

Pharmacogenetics in Primary Headache Disorders

Primary headache disorders, such as migraine, tension-type headache (TTH), and cluster headache, belong to the most common neurological disorders affecting a high percentage of people worldwide. Headache induces a high burden for the affected individuals on the personal level, with a strong impact on life quality, daily life management, and causes immense costs for the healthcare systems. Although a relatively broad spectrum of different pharmacological classes for the treatment of headache disorders are available, treatment effectiveness is often limited by high variances in therapy responses. Genetic variants can influence the individual treatment success by influencing pharmacokinetics or pharmacodynamics of the therapeutic as investigated in the research field of pharmacogenetics. This review summarizes the current knowledge on important primary headache disorders, including migraine, TTH, and cluster headache. We also summarize current acute and preventive treatment options for the three headache disorders based on drug classes and compounds taking important therapy guidelines into consideration. Importantly, the work summarizes and discusses the role of genetic polymorphisms regarding their impact on metabolism safety and the effect of therapeutics that are used to treat migraine, cluster headache, and TTH exploring drug classes such as nonsteroidal anti-inflammatory drugs, triptans, antidepressants, anticonvulsants, calcium channel blockers, drugs with effect on the renin-angiotensin system, and novel headache therapeutics such as ditans, anti-calcitonin-gene-related peptide antibodies, and gepants. Genetic variants in important phase I-, II-, and III-associated genes such as cytochrome P450 genes, UGT genes, and different transporter genes are scrutinized as well as variants in genes important for pharmacodynamics and several functions outside the pharmacokinetic and pharmacodynamic spectrum. Finally, the article evaluates the potential and limitations of pharmacogenetic approaches for individual therapy adjustments in headache disorders.

Additive Interaction Between Onabotulinumtoxin-A and Erenumab in Patients With Refractory Migraine

In the last decade, notable progresses have been observed in chronic migraine preventive treatments. According to the European Headache Federation and national provisions, onabotulinumtoxin-A (BTX-A) and monoclonal antibodies acting on the pathway of calcitonin gene-related peptide (CGRP-mAbs) should not be administered in combination due to supposed superimposable mechanism of action and high costs. On the other hand, preclinical observations demonstrated that these therapeutic classes, although operating directly or indirectly on the CGRP pathway, act on different fibers. Specifically, the CGRP-mAbs prevent the activation of the Aδ-fibers, whereas BTX-A acts on C-fibers. Therefore, it can be argued that a combined therapy may provide an additive or synergistic effect on the trigeminal nociceptive pathway. In the present study, we report a case series of 10 patients with chronic migraine who experienced significant benefits with the combination of both erenumab and BTX-A compared to each therapeutic strategy alone. A reduction in frequency and intensity of headache attacks (although not statistically significant probably due to the low sample size) was observed in migraine patients treated with a combined therapy with BTX-A and erenumab compared to both BTX-A and erenumab alone. Moreover, the combined therapy with BTX-A and erenumab resulted in a statistically significant reduction in the symptomatic drug intake and in migraine-related disability probably related to a reduced necessity or also to a better responsiveness to rescue treatments. Present data suggest a remodulation of current provisions depriving patients of an effective therapeutic strategy in peculiar migraine endophenotypes.

Comparing the Efficacy, Safety, and Superiority of Calcitonin Gene-Related Peptide Monoclonal Antibodies and Botox in Preventing and Treating Migraines

Both calcitonin gene-related peptide (CGRP) monoclonal antibodies (mAbs) and OnabotulinumtoxinA (botox) are used in the prevention of chronic migraines. However, it is not clear which is more effective overall. This review will compare the efficacy, side effects, cost-effectiveness, and other factors between CGRP mAbs and botox. We searched Pubmed and Google Scholar using the keywords migraines, CGRP mAbs, botox, efficacy, side effects, aura. All articles, including case-control/cohort studies, case series, case reports, randomized control trials, traditional/systematic reviews, were analyzed. CGRP mAbs and botox both reduce the frequency of migraines in patients. Patients have reported they decreased migraines' frequency and intensity in several studies after being given each medication. While CGRP mAbs are more recent medications, botox has been studied for more than a decade as a migraine preventative. Both drugs have minor short-term side effects, but some CGRP mAbs may cause persistent constipation too. CGRP mAbs are self-injected every month, and botox is physician-injected every three months, making it easier to stay compliant. While both medications are expensive, botox has a lower cost over time. Botox is more effective prophylaxis of migraines based on the articles that were reviewed. While both CGRP mAbs and botox are efficacious and tolerable, botox has been studied longer, has fewer side effects, is more cost-effective, and is easier to comply with.

Pharmacotherapy failure and progression to botulinum toxin injection in vestibular migraine

Objective

Given the lack of evidence on patients with medically refractory vestibular migraine, this study aimed to identify factors associated with pharmacotherapy failure and progression to botulinum toxin injection in vestibular migraine.

Methods

A retrospective cohort study was conducted on definite vestibular migraine patients from September 2015 to July 2019 who completed the Dizziness Handicap Inventory at least six weeks apart..

Results

The study comprised 47 patients (mean age = 50.2 ± 15.8 years), with a mean follow-up time of 6.0 ± 6.0 months. The mean pre-treatment Dizziness Handicap Inventory score was 57.5 ± 23.5, with a mean reduction of 17.3 ± 25.2 (p < 0.001) at last follow up. Oscillopsia (r = 0.458, p = 0.007), failure of first medication (r = 0.518, p = 0.001) and pre-treatment Dizziness Handicap Inventory question 15 (an emotional domain question) score (r = 0.364, p = 0.019) were the only variables significantly correlated with progression to botulinum toxin injection.

Conclusion

Motion hypersensitivity, failure of first medication, and fear of social stigmatisation suggest a decreased treatment response. These symptoms may require more aggressive treatment at an earlier stage.

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

OnabotulinumtoxinA: A Review in the Prevention of Chronic Migraine

An intramuscular formulation of onabotulinumtoxinA (onabotA; Botox®) is currently the only therapy specifically approved for the prevention of headaches in adults with chronic migraine (CM) in the EU and North America. This article provides a narrative review of relevant data on the drug in this indication from an EU perspective. OnabotA was originally approved on the basis of pooled data from two phase III studies (PREEMPT 1 and 2). In these pivotal studies, injection of up to five cycles of onabotA (155-195 U/cycle) at 12-week intervals was generally well tolerated and effective in producing statistically significant and clinically meaningful improvements in headache symptoms, acute headache pain medication usage, headache impact and health-related quality of life in adults with CM, of whom approximately two-thirds were acute medication overusers and approximately one-third had failed to respond to ≥ 3 prior oral prophylactic therapies. More recently, the efficacy and tolerability of onabotA over a period of 1 year in the PREEMPT programme has been substantiated and extended by the results of a long-term phase IV study (COMPEL), in which patients received up to nine treatment cycles over a period of 2 years, and by findings from several real-world clinical practice studies from Europe, including the prospective multinational REPOSE and CM-PASS studies. In conclusion, the totality of evidence from clinical trials and real-world studies indicates that onabotA is an effective and generally well tolerated option for the prevention of CM that may be particularly useful for patients who have previously failed to respond to or are intolerant of commonly prescribed oral prophylactics.

Association between Cervical Spondylosis and Migraine: A Nationwide Retrospective Cohort Study

Background: Few studies have investigated the longitudinal association between cervical spondylosis (CS) and migraine by using a nationwide population-based database. Methods: We conducted a retrospective cohort study from 2000 to 2011 identifying 27,930 cases of cervical spondylosis and 111,720 control subjects (those without cervical spondylosis) from a single database. The subjects were frequency-matched on the basis of sex, age, and diagnosis date. The non- cervical spondylosis cohort was four times the size of the cervical spondylosis cohort. To quantify the effects of cervical spondylosis on the risk of migraine, univariate and multivariate Cox proportional hazard regression analyses were used to calculate the hazard ratio (HR), and 95% confidence interval (CI). Results: After a 10-year follow-up controlling for potential confounding factors, overall migraine incidence was higher in the cervical spondylosis cohort than in the non-cervical spondylosis cohort (5.16 and 2.09 per 1000 people per year, respectively; crude hazard ratio = 2.48, 95% confidence interval = 2.28-2.69), with an adjusted hazard ratio of 2.03 (95% confidence interval = 1.86-2.22) after accounting for sex, age, comorbidities, and medication. Individuals with myelopathy in the cervical spondylosis cohort had a 2.19 times (95% confidence interval = 1.80-2.66) higher incidence of migraine when compared than did those in the non- cervical spondylosis cohort. Conclusions: Individuals with cervical spondylosis exhibited a higher risk of migraine than those without cervical spondylosis. The migraine incidence rate was even higher among individuals with cervical spondylotic myelopathy.

Injection Therapy for Headache and Facial Pain

Peripheral nerve blocks are an increasingly viable treatment option for selected groups of headache patients, particularly those with intractable headache or facial pain. Greater occipital nerve block, the most widely used local anesthetic procedure in headache conditions, is particularly effective, safe, and easy to perform in the office. Adverse effects are few and infrequent. These procedures can result in rapid relief of pain and allodynia, and effects last for several weeks or months. Use of nerve block procedures and potentially onabotulinum toxin therapy should be expanded for patients with intractable headache disorders who may benefit, although more studies are needed for efficacy and clinical safety.

Onabotulinumtoxin-A treatment in Greek patients with chronic migraine

Background

Chronic migraine is a disabling condition, with limited treatment options. We conducted an open label, single arm, prospective clinical trial, to assess the efficacy and safety of onabotulinumtoxin-A in Greek patients with chronic migraine. Since recent evidence suggests that a meaningful clinical response may be delayed until after a third onabotulinumtoxin-A administration, we aimed at assessing outcomes at this time point.

Methods

A total of 119 patients with CM, scheduled to be treated with Onabotulinumtoxin-A (Botox ®) every 3 months, according to the approved indication and standard clinical practice, were prospectively enrolled. Data documenting changes from baseline (T0—trimester before Onabotulinumtoxin-A first administration) to the period after its third administration (T3) in (i) mean number of monthly headache days (ii) migraine severity as expressed by the mean number of days with peak headache intensity of >4/10 in a 0–10 numerical scale, and (iii) mean number of days with use of any acute headache medication, were collected from patients’ headache diaries at each visit.

Results

Of the 119 patients, a total of 81 received 3 courses of onabotulinumtoxin-A and were included in the efficacy population. In those 81 patients, there was a significant decrease in mean headache days/month between T0 and T3 (21.3 ± 5.4 vs 7.7 ± 4.8; P < 0.001); a significant decrease in days with peak headache intensity of >4/10 (11.9 ± 5.5 vs 3.7 ± 3.3; P < 0.001) and finally, the change in days using acute headache medications per month between was also significant (16.2 ± 7.8 vs 5.2 ± 4.3; P < 0.001). Adverse events were few and of non- serious nature.

Conclusion

Our results strongly support the use of onabotulinumtoxin-A for the prophylaxis of CM, as this intervention proved effective, safe and well tolerated in our cohort of Greek patients.

Alleviation of pain in painful diabetic neuropathy

INTRODUCTION

Painful diabetic neuropathy (PDN) is a disabling pain condition. Its pathomechanism remains unknown, but a sensitization and neuronal hyperexcitabilty have been suggested. Only symptomatic pharmacological pain management treatment is currently available.

AREAS COVERED

The origin of PDN is enigmatic, and the evidence-based therapeutic guidelines therefore consist only of antidepressants and antiepileptics as first-line recommended drugs. This article relates to a MEDLINE/PubMed systematic search (2005-2015).

EXPERT OPINION

The results of the meta-analysis from the aspect of the efficacy of amitriptyline, duloxetine, venlafaxine, gabapentin and pregabalin are favorable, but the placebo response rate is relatively high in patients with neuropathic pain. For personalization of the medication of PDN patients, the optimum dosing, the genotyping of the metabolizing enzymes and optimum biomarkers are needed. As concerns the future perspectives, specific sodium channel subtype inhibitors acting on peripheral nociceptive neurons or modified T-type voltage-gated calcium channel blockers may be promising targets for pharmaceutical innovations. Another attractive strategy for the treatment is based on the effects of monoclonal antibodies against nerve growth factor, sodium channels, specific receptor and cytokines. Botulinum toxin A, capsaicin patch and spinal cord stimulation therapies are the nearest future therapeutic options for the treatment of PDN patients.

Cutaneous Adverse Effects of Neurologic Medications

Life-threatening and benign drug reactions occur frequently in the skin, affecting 8 % of the general population and 2-3 % of all hospitalized patients, emphasizing the need for physicians to effectively recognize and manage patients with drug-induced eruptions. Neurologic medications represent a vast array of drug classes with cutaneous side effects. Approximately 7 % of the United States (US) adult population is affected by adult-onset neurological disorders, reflecting a large number of patients on neurologic drug therapies. This review elucidates the cutaneous reactions associated with medications approved by the US Food and Drug Administration (FDA) to treat the following neurologic pathologies: Alzheimer disease, amyotrophic lateral sclerosis, epilepsy, Huntington disease, migraine, multiple sclerosis, Parkinson disease, and pseudobulbar affect. A search of the literature was performed using the specific FDA-approved drug or drug classes in combination with the terms 'dermatologic,' 'cutaneous,' 'skin,' or 'rash.' Both PubMed and the Cochrane Database of Systematic Reviews were utilized, with side effects ranging from those cited in randomized controlled trials to case reports. It behooves neurologists, dermatologists, and primary care physicians to be aware of the recorded cutaneous adverse reactions and their severity for proper management and potential need to withdraw the offending medication.