Phase 3 randomized, placebo-controlled study of galcanezumab in patients with chronic cluster headache: Results from 3-month double-blind treatment

CGRP Modulating Therapies: An Update

INTRODUCTION

Calcitonin-gene related peptide (CGRP) is a vasoactive neuropeptide involved in the pathophysiology ofmigraine. CGRP has been targeted for both preventive and acute treatment of migraine.

OBJECTIVE

Provide a summary of the most clinically relevant literature surrounding CGRP modulating therapies.

METHODS

This update on CGRP modulating therapies includes articles selected as most clinically relevant by theauthors.

CONCLUSION

CGRP modulating therapies are an exciting new addition to migraine treatment given their safety andtolerability. Additionally, compared to traditional migraine preventive medication these treatments are migrainespecific.Further real-world and clinical data is ongoing to better understand these treatments that continue to gainfavor in the management of migraine.

Recent advances in diagnosing, managing, and understanding the pathophysiology of cluster headache

Cluster headache, characterised by attacks of severe, recurrent, unilateral headache and ipsilateral cranial autonomic symptoms, remains a primary headache with an elusive pathophysiology. Recent advances have introduced effective treatments and broadened understanding of the clinical features of cluster headache. These features are similar in patients globally, but regional differences in prevalence and burden exist. International collaborations have led to identification of eight genetic loci associated with cluster headache. The pathophysiological mechanisms are still not fully understood but recent studies show that targeting the trigeminal autonomic reflex by neurostimulation, or targeting the neuropeptide calcitonin gene-related peptide (CGRP), might lessen the attack burden. The US Food and Drug Administration has approved galcanezumab, a monoclonal antibody targeting CGRP, as the first specific preventive treatment for episodic cluster headache. However, a preventive effect was not replicated in chronic cluster headache, and the European Medicines Agency did not approve galcanezumab, restricting its availability in Europe. Owing to the low prevalence of cluster headache, continued collaboration through multicentre clinical trials and data sharing will be imperative for further breakthroughs in understanding and management.

Blood pressure monitoring in elderly migraineurs starting an anti-CGRP monoclonal antibody: a real-world prospective study

BACKGROUND

While monoclonal antibodies (mAbs) targeting the CGRP pathway have revolutionized migraine management due to their improved tolerance and adherence, concerns remain about their potential impact on blood pressure (BP), especially in older patients, due to CGRP-mediated vasodilation blockade. Given the growing use of these therapies in older populations, assessing their cardiovascular (CV) safety is of paramount importance.

METHODS

This multicentric observational prospective study focused on migraine sufferers aged ≥ 60 who began erenumab, galcanezumab, or fremanezumab for prevention. Baseline, three-month, and twelve-month BP measurements were collected. Changes in antihypertensive medication and "Newly or Worsened Hypertensive" patients (NWHP) were assessed.

RESULTS

Among 155 patients receiving anti-CGRP mAbs (40 Erenumab, 47 Galcanezumab, 68 Fremanezumab), 42.5% had hypertension history and 39% were on antihypertensive treatment. No significant systolic or diastolic BP changes occurred at any time point compared to baseline (all p > 0.05), with no differences between the three groups. After one year, 20/155 (12.9%) patients were considered NWHP; 11/20 had prior hypertension, and 5/11 adjusted antihypertensive therapy. Among 9/20 newly hypertensive patients, 5/9 had a single measurement above the normal threshold with no requirement for new pharmacological therapy. A higher baseline BP value was associated with increased BP (p = 0.002).

CONCLUSIONS

The study concludes that treatment with anti-CGRP mAbs over one year does not significantly affect BP in patients aged ≥ 60, nor does it increase the incidence of hypertension compared to general population trends. Nonetheless, continuous monitoring and further long-term studies are necessary to fullya scertain the cardiovascular safety of these medications in the elderly.

Developments in targeting calcitonin gene-related peptide

INTRODUCTION

Calcitonin Gene-Related Peptide (CGRP)-targeted therapy has revolutionized migraine treatment since its first approval in 2018. CGRP-targeted therapy includes monoclonal antibodies (mAbs) and gepants, which modulate trigeminal nociceptive and inflammatory responses, alleviating pain sensitization involved in migraine pathogenesis. CGRP-targeted therapy is effective not only for migraine but also for other chronic headache disorders that share the CGRP pathway.

AREAS COVERED

The authors review the latest developments and evidence for CGRP-targeted therapy for episodic migraine and chronic migraine. In addition, the authors discuss the emerging evidence on response prediction, menstrual migraine, vestibular migraine, idiopathic intracranial hypertension, post-traumatic headache, and the relationship between selected migraine comorbidities and CGRP.

EXPERT OPINION

Since the launch of CGRP-targeted therapy, many practical issues have been raised. Generally, it's safe to combine CGRP-targeted mAbs and gepants; this is an excellent option for patients with partial response. When considering stopping CGRP-targeted therapy, although a disease-modifying effect is likely, the optimal time for discontinuation remains unknown. Finally, beyond migraine, CGRP-targeted therapy may be used for other chronic pain disorders and psychological comorbidities.

Cluster headache: an update on clinical features, epidemiology, pathophysiology, diagnosis, and treatment

Cluster headache (CH) is one of the worst primary headaches that remain underdiagnosed and inappropriately treated. There are recent advances in the understanding of this disease and available treatments. This paper aims to review CH's recent clinical and pathophysiological findings, diagnosis, and treatment. We performed a narrative literature review on the socio-demographics, clinical presentations, pathophysiological findings, and diagnosis and treatment of CH. CH affects 0.1% of the population with an incidence of 2.07-9.8/100,00 person-years-habitants, a mean prevalence of 53/100,000 inhabitants (3-150/100,000 inhabitants). The male-to-female ratio remains inconclusive, as the ratio of 4.3:1 has recently been modified to 1.3-2.6, possibly due to previous misdiagnosis in women. Episodic presentation is the most frequent (80%). It is a polygenetic and multifactorial entity that involves dysfunction of the trigeminovascular system, the trigeminal autonomic reflex, and the hypothalamic networks. An MRI of the brain is mandatory to exclude secondary etiologies. There are effective and safe pharmacological treatments oxygen, sphenopalatine, and great occipital nerve block, with the heterogeneity of clinical trial designs for patients with CH divided into acute, transitional, or bridge treatment (prednisone) and preventive interventions. In conclusion, CH remains underdiagnosed, mainly due to a lack of awareness within the medical community, frequently causing a long delay in reaching a final diagnosis. Recent advances in understanding the principal risk factors and underlying pathophysiology exist. There are new therapeutic possibilities that are effective for CH. Indeed, a better understanding of this challenging pathology will continue to be a subject of research, study, and discoveries in its diagnostic and therapeutic approach.

Commentary on 2022 guidelines on clinical trial design in cluster headache and further suggestions

BACKGROUND

New guidelines for cluster headache clinical trials were recently published. We welcome these new guidelines and raise additional considerations in trial methodologies.

MAIN BODY

We present non-inferiority trials to overcome ethical issues with placebo use, and additionally discuss issues with trial recruitment.

CONCLUSIONS

We highlight some possible issues and solutions to be considered with the recently published cluster headache trial guidelines.

Reduced plasma calcitonin gene-related peptide level identified in cluster headache: A prospective and controlled study

BACKGROUND

The role of calcitonin gene-related peptide (CGRP) in the cyclic pattern of cluster headache is unclear. To acquire biological insight and to comprehend why only episodic cluster headache responds to CGRP monoclonal antibodies, we examined whether plasma CGRP changes between disease states (i.e. bout, remission and chronic) and controls.

METHODS

The present study is a prospective case-control study. Participants with episodic cluster headache were sampled twice (bout and remission). Participants with chronic cluster headache and controls were sampled once. CGRP concentrations were measured in plasma with a validated radioimmunoassay.

RESULTS

Plasma was collected from 201 participants diagnosed with cluster headache according to the International Classification of Headache Disorders, 3rd edition, and from 100 age- and sex-matched controls. Overall, plasma CGRP levels were significantly lower in participants with cluster headache compared to controls (p < 0.05). In episodic cluster headache, CGRP levels were higher in bout than in remission (mean difference: 17.1 pmol/L, 95% confidence interval = 9.8-24.3, p < 0.0001). CGRP levels in bout were not different from chronic cluster headache (p = 0.266).

CONCLUSIONS

Plasma CGRP is unsuitable as a diagnostic biomarker of cluster headache or its disease states. The identified reduced CGRP levels suggest that CGRPs role in cluster headache is highly complex and future investigations are needed into the modulation of CGRP and its receptors.

Efficacy and safety of galcanezumab as chronic cluster headache preventive treatment under real world conditions: Observational prospective study

BACKGROUND

Calcitonin gene-related peptide has shown to play a central role in cluster headache (CH) pathophysiology. A clinical trial with galcanezumab was carried out in chronic cluster headache (CCH) but did not meet its primay endpoint. However, its off-label use in patients with CCH refractory to other therapies could be considered. We aimed to asses the efficacy and safety of galcanezumab as CCH preventive treatment in a real-life setting.

METHODS

An observational study was conducted. Patients with CCH who received at least one dose of 240 mg of galcanezumab.

RESULTS

Twenty-one patients who tried a mean of 6.3 ± 1.9 preventive therapies, including onabotulinumtoxinA in 90.5%. At baseline, the median of frequency was 60 (37.5-105) monthly attacks with 10 (8.3-10) points in pain intensity (Numerical Rating Scale). After one month, the frequency decreased to 31 (10.5-45) (p = 0.003) with 8.5 (8-9.5) intensity (p = 0.007); 10 (47.6%) patients were 50% responders of whom four (19%) were 75% responders. Of the 15 patients with 3 months of follow-up, seven (46.6%) reduced their frequency by 50% and four (26.6%) by 75%, with 40 (10-60) monthly attacks (p = 0.07) and pain intensity of 8 (5-10) (p = 0.026). Some 52% patients experienced adverse events, mostly mild.

CONCLUSIONS

In our cohort of refractory CCH, galcanezumab was effective in almost 50% of patients. This finding supports individual off-label treatment attempts.

Drug-related side effects and adverse reactions in the treatment of migraine: a bibliometric and visual analysis

Background

Migraine imposes a substantial global burden, impacting patients and society. Pharmacotherapy, as a primary treatment, entails specific adverse reactions. Emphasizing these reactions is pivotal for improving treatment strategies and enhancing patients' well-being. Thus, we conducted a comprehensive bibliometric and visual analysis of relevant literature.

Methodology

We conducted a comprehensive search on the Science Citation Index Expanded within the Web of Science, restricting the literature for analysis based on criteria such as document type, publication date, and language. Subsequently, we utilized various analytical tools, including VOSviewer, Scimago Graphica, the R package 'bibliometrix', CiteSpace, and Excel programs, for a meticulous examination and systematic organization of data concerning journals, authors, countries/regions, institutions, keywords, and references.

Results

By August 31, 2023, the literature was distributed across 379 journals worldwide, authored by 4,235 individuals from 1726 institutions. It featured 2,363 keywords and 38,412 references. 'HEADACHE' led in publication count, with 'SILBERSTEIN S' as the most prolific author. The United States ranked highest in publication volume, with 'UNIV COPENHAGEN' leading among institutions.

Conclusion

Our research findings indicate that researchers in the field continue to maintain a focus on the calcitonin gene-related peptide (CGRP) system and explore diverse mechanisms for drug development through the application of novel biotechnological approaches. Furthermore, it is imperative to enhance the assessment of clinical trial outcomes, consistently monitor the efficacy and safety of prominent drugs such as Erenumab and Fremanezumab. There is a need for further evaluation of acute and preventive treatments tailored to different populations and varying types of migraine.

Drug-related side effects and adverse reactions in the treatment of migraine: a bibliometric and visual analysis

BACKGROUND

Migraine imposes a substantial global burden, impacting patients and society. Pharmacotherapy, as a primary treatment, entails specific adverse reactions. Emphasizing these reactions is pivotal for improving treatment strategies and enhancing patients' well-being. Thus, we conducted a comprehensive bibliometric and visual analysis of relevant literature.

METHODOLOGY

We conducted a comprehensive search on the Science Citation Index Expanded within the Web of Science, restricting the literature for analysis based on criteria such as document type, publication date, and language. Subsequently, we utilized various analytical tools, including VOSviewer, Scimago Graphica, the R package 'bibliometrix', CiteSpace, and Excel programs, for a meticulous examination and systematic organization of data concerning journals, authors, countries/regions, institutions, keywords, and references.

RESULTS

By August 31, 2023, the literature was distributed across 379 journals worldwide, authored by 4,235 individuals from 1726 institutions. It featured 2,363 keywords and 38,412 references. 'HEADACHE' led in publication count, with 'SILBERSTEIN S' as the most prolific author. The United States ranked highest in publication volume, with 'UNIV COPENHAGEN' leading among institutions.

CONCLUSION

Our research findings indicate that researchers in the field continue to maintain a focus on the calcitonin gene-related peptide (CGRP) system and explore diverse mechanisms for drug development through the application of novel biotechnological approaches. Furthermore, it is imperative to enhance the assessment of clinical trial outcomes, consistently monitor the efficacy and safety of prominent drugs such as Erenumab and Fremanezumab. There is a need for further evaluation of acute and preventive treatments tailored to different populations and varying types of migraine.

CCH attack frequency reduction after psilocybin correlates with hypothalamic functional connectivity

OBJECTIVE

To evaluate the feasibility and prophylactic effect of psilocybin as well as its effects on hypothalamic functional connectivity (FC) in patients with chronic cluster headache (CCH).

BACKGROUND

CCH is an excruciating and difficult-to-treat disorder with incompletely understood pathophysiology, although hypothalamic dysfunction has been implicated. Psilocybin may have beneficial prophylactic effects, but clinical evidence is limited.

METHODS

In this small open-label clinical trial, 10 patients with CCH were included and maintained headache diaries for 10 weeks. Patients received three doses of peroral psilocybin (0.14 mg/kg) on the first day of weeks five, six, and seven. The first 4 weeks served as baseline and the last 4 weeks as follow-up. Hypothalamic FC was determined using functional magnetic resonance imaging the day before the first psilocybin dose and 1 week after the last dose.

RESULTS

The treatment was well tolerated. Attack frequency was reduced by mean (standard deviation) 31% (31) from baseline to follow-up (pFWER  = 0.008). One patient experienced 21 weeks of complete remission. Changes in hypothalamic-diencephalic FC correlated negatively with a percent change in attack frequency (pFWER  = 0.03, R = -0.81), implicating this neural pathway in treatment response.

CONCLUSION

Our results indicate that psilocybin may have prophylactic potential and implicates the hypothalamus in possible treatment response. Further clinical studies are warranted.

Baseline demographics and disease characteristics of patients with episodic or chronic cluster headache: data from two phase 3 randomized clinical trials in Europe and North America

Objective

Two phase 3 galcanezumab trials were conducted in Europe and North America to analyze the reduction of weekly cluster headache (CH) attack frequency in populations with episodic and chronic CH. The current study aims to illustrate prospectively recorded baseline clinical data from these trials and to identify possible predictors of response.

Methods

Patients (aged 18-65 years) met The International Classification of Headache Disorders 3rd edition-beta criteria for CH. Attacks were evaluated using an electronic headache diary for 7-day (episodic) or 14-day (chronic) eligibility assessments before patients were randomized 1:1 to monthly subcutaneous galcanezumab 300 mg or placebo.

Results

Data were collected from 106 patients with episodic and 237 with chronic CH. Overall, the mean age [standard deviation] was 45.4 [11.0] years; patients were predominantly White (84.5%), male (75.8%), and European (77.6%). Patients with episodic CH reported 17.5 [10.0] attacks/week; patients with chronic CH reported 18.8 [10.2] attacks/week. The average pain severity score (range 0-4) was 2.5 [0.7] for episodic CH and 2.7 [0.7] for chronic CH. Higher attack frequency was a possible predictor of response to galcanezumab; potential negative predictors of response were greater attack severity and duration.

Conclusion

This large dataset of patients with CH provides reliable systematically and prospectively collected information on disease characteristics. The analysis in episodic CH underscores potential predictors of response worth considering for future CH trial design.

Clinical Trial Registration

ClinicalTrials.gov, identifiers: NCT02397473 and NCT02438826.

Health equity, care access and quality in headache - part 2

BACKGROUND

Headache disorders are a global public health concern affecting diverse populations. This review examines headache service organizations in low-, middle-, and high-income countries. It addresses global challenges in pharmacological headache treatment, with a focus on safety, tolerability, reproductive and child health, and outlines disparities in accessing innovative treatments worldwide.

MAIN BODY

Organized headache services are essential due to the wide prevalence and varying severity of headache disorders. The tiered headache service model is globally recognized, although its implementation varies based on financial and workforce considerations. Headache burden affects well-being, causing disability, economic challenges, and work limitations, irrespective of location or income. All nations still require improved diagnosis and treatment, and the majority of countries face obstacles including limited access, awareness, economic barriers, and inadequate health policies. Provided adequate internet availability, telemedicine could help improve health equity by expanding access to headache care, since it can offer patients access to services without lengthy waiting times or extensive travel and can provide healthcare unavailable in underserved areas due to staff shortages. Numerous health disparities restrict global access to many headache medications, especially impacting individuals historically excluded from randomized controlled trials, such as those with cardiovascular and cerebrovascular conditions, as well as pregnant women. Furthermore, despite advancements in researching migraine treatments for young patients, the options for treatment remain limited. Access to headache treatment relies on factors like medication availability, approval, financial coverage, and healthcare provider expertise. Inadequate public awareness leads to neglect by policymakers and undertreatment by patients and healthcare providers. Global access discrepancies are exacerbated by the introduction of novel disease-specific medications, particularly impacting Asian, African, and Latin American nations excluded from clinical trials. While North America and Europe experience broad availability of migraine treatments, the majority of countries worldwide lack access to these therapies.

CONCLUSIONS

Healthcare disparities, treatment access, and medication availability are concerning issues in headache medicine. Variations in national healthcare systems impact headache management, and costly innovative drugs are widening these gaps. Healthcare practitioners and experts should acknowledge these challenges and work towards minimizing access barriers for equitable global headache care in the future.

Association of Clinical and Neuroanatomic Factors With Response to Ventral Tegmental Area DBS in Chronic Cluster Headache

BACKGROUND AND OBJECTIVES

Deep brain stimulation (DBS) of the ventral tegmental area (VTA) is a surgical treatment option for selected patients with refractory chronic cluster headache (CCH). We aimed to identify clinical and structural neuroimaging factors associated with response to VTA DBS in CCH.

METHODS

This prospective observational cohort study examines consecutive patients with refractory CCH treated with VTA DBS by a multidisciplinary team in a single tertiary neuroscience center as part of usual care. Headache diaries and validated questionnaires were completed at baseline and regular follow-up intervals. All patients underwent T1-weighted structural MRI before surgery. We compared clinical features using multivariable logistic regression and neuroanatomic differences using voxel-based morphometry (VBM) between responders and nonresponders.

RESULTS

Over a 10-year period, 43 patients (mean age 53 years, SD 11.9), including 29 male patients, with a mean duration of CCH 12 years (SD 7.4), were treated and followed up for at least 1 year (mean follow-up duration 5.6 years). Overall, there was a statistically significant improvement in median attack frequency from 140 to 56 per month (Z = -4.95, p < 0.001), attack severity from 10/10 to 8/10 (Z = -4.83, p < 0.001), and duration from 110 to 60 minutes (Z = -3.48, p < 0.001). Twenty-nine (67.4%) patients experienced ≥50% improvement in attack frequency and were therefore classed as responders. There were no serious adverse events. The most common side effects were discomfort or pain around the battery site (7 patients) and transient diplopia and/or oscillopsia (6 patients). There were no differences in demographics, headache characteristics, or comorbidities between responders and nonresponders. VBM identified increased neural density in nonresponders in several brain regions, including the orbitofrontal cortex, anterior cingulate cortex, anterior insula, and amygdala, which were statistically significant (p < 0.001).

DISCUSSION

VTA DBS showed no serious adverse events, and, although there was no placebo control, was effective in approximately two-thirds of patients at long-term follow-up. This study did not reveal any reliable clinical predictors of response. However, nonresponders had increased neural density in brain regions linked to processing of pain and autonomic function, both of which are prominent in the pathophysiology of CCH.

Cluster headache: state of the art in treatment

Cluster headache (CH) is the most common and devastating autonomic headache with multiple and recent advances in treatment. However, it usually goes unrecognized and is found to have a delayed and inappropriate treatment. This paper aims to review the current therapeutic options for patients with CH. We conducted a narrative literature review on the treatments available for this condition using the American Academy of Neurology (AAN) classification of therapeutic evidence. We found effective and safe pharmacological and non-pharmacological therapies with heterogeneity of clinical trial designs for patients with CH, and they are divided into three phases, namely, transitional, acute, and preventive interventions. Prednisone (A) is the most studied treatment in the transitional phase; acute attacks are treated using triptans (A), oxygen (A), and non-invasive transcutaneous vagal nerve stimulation (A). Verapamil (A) and monoclonal antibodies (possible A) are considered the first options in preventive treatments, followed by multiple pharmacological and non-pharmacological options in prophylactic treatments. In conclusion, numerous effective and safe treatments are available in treating patients with episodic, chronic, and pharmacoresistant CH according to the clinical profile of each patient.

European Academy of Neurology guidelines on the treatment of cluster headache

BACKGROUND AND PURPOSE

Cluster headache is a relatively rare, disabling primary headache disorder with a major impact on patients' quality of life. This work presents evidence-based recommendations for the treatment of cluster headache derived from a systematic review of the literature and consensus among a panel of experts.

METHODS

The databases PubMed (Medline), Science Citation Index, and Cochrane Library were screened for studies on the efficacy of interventions (last access July 2022). The findings in these studies were evaluated according to the recommendations of the European Academy of Neurology, and the level of evidence was established using GRADE (Grading of Recommendations Assessment, Development, and Evaluation).

RECOMMENDATIONS

For the acute treatment of cluster headache attacks, there is a strong recommendation for oxygen (100%) with a flow of at least 12 L/min over 15 min and 6 mg subcutaneous sumatriptan. Prophylaxis of cluster headache attacks with verapamil at a daily dose of at least 240 mg (maximum dose depends on efficacy and tolerability) is recommended. Corticosteroids are efficacious in cluster headache. To reach an effect, the use of at least 100 mg prednisone (or equivalent corticosteroid) given orally or at up to 500 mg iv per day over 5 days is recommended. Lithium, topiramate, and galcanezumab (only for episodic cluster headache) are recommended as alternative treatments. Noninvasive vagus nerve stimulation is efficacious in episodic but not chronic cluster headache. Greater occipital nerve block is recommended, but electrical stimulation of the greater occipital nerve is not recommended due to the side effect profile.

Mode and site of action of therapies targeting CGRP signaling

Targeting CGRP has proved to be efficacious, tolerable, and safe to treat migraine; however, many patients with migraine do not benefit from drugs that antagonize the CGRPergic system. Therefore, this review focuses on summarizing the general pharmacology of the different types of treatments currently available, which target directly or indirectly the CGRP receptor or its ligand. Moreover, the latest evidence regarding the selectivity and site of action of CGRP small molecule antagonists (gepants) and monoclonal antibodies is critically discussed. Finally, the reasons behind non-responders to anti-CGRP drugs and rationale for combining and/or switching between these therapies are addressed.

Current treatment options for cluster headache: limitations and the unmet need for better and specific treatments-a consensus article

AIM

Treatment for cluster headache is currently based on a trial-and-error approach. The available preventive treatment is unspecific and based on few and small studies not adhering to modern standards. Therefore, the authors collaborated to discuss acute and preventive treatment in cluster headache, addressing the unmet need of safe and tolerable preventive medication from the perspectives of people with cluster headache and society, headache specialist and cardiologist.

FINDINGS

The impact of cluster headache on personal life is substantial. Mean annual direct and indirect costs of cluster headache are more than 11,000 Euros per patient. For acute treatment, the main problems are treatment response, availability, costs and, for triptans, contraindications and the maximum use allowed. Intermediate treatment with steroids and greater occipital nerve blocks are effective but cannot be used continuously. Preventive treatment is sparsely studied and overall limited by relatively low efficacy and side effects. Neurostimulation is a relevant option for treatment-refractory chronic patients. From a cardiologist's perspective use of verapamil and triptans may be worrisome and regular follow-up is essential when using verapamil and lithium.

CONCLUSION

We find that there is a great and unmet need to pursue novel and targeted preventive modalities to suppress the horrific pain attacks for people with cluster headache.

Trigeminal Autonomic Cephalalgias and Neuralgias in Children and Adolescents: a Narrative Review

PURPOSE OF REVIEW

To summarize the available literature as well as the authors' experience on trigeminal autonomic cephalalgias (TACs) and cranial neuralgias in children and adolescents.

RECENT FINDINGS

While TACs and cranial neuralgias are rare in children, several recent case series have been published. TACs in children share most of the clinical features of TACs in adults. However, there are many reported cases with clinical features which overlap more than one diagnosis, suggesting that TACs may be less differentiated in youth. Indomethacin-responsive cases of cluster headache and SUNCT/SUNA have been reported in children, whereas in adults indomethacin is usually reserved for paroxysmal hemicrania and hemicrania continua. Neuralgias appear to be rare in children. Clinical features are often similar to adult cases, though clinicians should maintain a high index of suspicion for underlying causes.

Management of cluster headache: Treatments and their mechanisms

BACKGROUND

The management of cluster headache is similar to that of other primary headache disorders and can be broadly divided into acute and preventive treatments. Acute treatments for cluster headache are primarily delivered via rapid, non-oral routes (such as inhalation, nasal, or subcutaneous) while preventives include a variety of unrelated treatments such as corticosteroids, verapamil, and galcanezumab. Neuromodulation is becoming an increasingly popular option, both non-invasively such as vagus nerve stimulation when medical treatment is contraindicated or side effects are intolerable, and invasively such as occipital nerve stimulation when medical treatment is ineffective. Clinically, this collection of treatment types provides a range of options for the informed clinician. Scientifically, this collection provides important insights into disease mechanisms.

METHODS

Two authors performed independent narrative reviews of the literature on guideline recommendations, clinical trials, real-world data, and mechanistic studies.

RESULTS

Cluster headache is treated with acute treatments, bridge treatments, and preventive treatments. Common first-line treatments include subcutaneous sumatriptan and high-flow oxygen as acute treatments, corticosteroids (oral or suboccipital injections) as bridge treatments, and verapamil as a preventive treatment. Some newer acute (non-invasive vagus nerve stimulation) and preventive (galcanezumab) treatments have excellent clinical trial data for episodic cluster headache, while other newer treatments (occipital nerve stimulation) have been specifically tested in treatment-refractory chronic cluster headache. Most treatments are suspected to act on the trigeminovascular system, the autonomic system, or the hypothalamus.

CONCLUSIONS

The first-line treatments have not changed in recent years, but new treatments have provided additional options for patients.

Ten open questions in migraine prophylaxis with monoclonal antibodies blocking the calcitonin-gene related peptide pathway: a narrative review

The monoclonal antibodies (mAbs) blocking the calcitonin-gene related peptide (CGRP) pathway, collectively called here "anti-CGRP/rec mAbs", have dramatically improved preventive migraine treatment. Although their efficacy and tolerability were proven in a number of randomized controlled trials (RCTs) and, maybe even more convincingly, in real world settings, a number of open questions remain. In this narrative review, we will analyze published data allowing insight in some of the uncertainties related to the use of anti-CGRP/rec mAbs in clinical practice: their differential efficacy in migraine subtypes, outcome predictors, switching between molecules, use in children and adolescents, long-term treatment adherence and persistence, effect persistence after discontinuation, combined treatment with botulinum toxin or gepants, added-value and cost effectiveness, effectiveness in other headache types, and potential contraindications based on known physiological effects of CGRP. While recent studies have already provided hints for some of these questions, many of them will not find reliable and definitive answers before larger studies, registries or dedicated RCTs are available.

Adapting psychedelic medicine for headache and chronic pain disorders

INTRODUCTION

While the majority of current research and development surrounds depression, demoralization, and substance use disorders, there are numerous reports of psychedelics having beneficial effects in other branches of medicine, including for headache disorders and chronic pain.

AREAS COVERED

This perspective reviews conventional forms of treatment for headache and other chronic pain disorders and describes historical, recent, and ongoing investigations of the therapeutic effects of psychedelics in these disorders. The first two clinical trials of psilocybin in headache disorders and recent case reports of psilocybin mushroom self-administration in chronic pain patients are described. This perspective highlights several factors related to the application of psychedelics in chronic pain disorders, comparing this with the standard psychedelic-assisted psychotherapy model of treatment.

EXPERT OPINION

When faced with a more constricted view of psychedelic medicine that features larger doses, underscores subjective effects in the mediation of therapeutic outcomes, and requires adjunctive psychotherapy to ensure safety and efficacy, the application of psychedelics in headache and chronic pain disorders may face challenges. It will be important to allow for flexibility and adaptation in protocols to evaluate different treatment paradigms, mechanisms of action, and the range of pharmacologic and extra-pharmacologic factors that affect psychedelic treatment outcomes.

Obstetric and Gynecologic Disorders and the Nervous System

OBJECTIVE

This article discusses obstetric and gynecologic associations with common neurologic disorders.

LATEST DEVELOPMENTS

Neurologic complications of obstetric and gynecologic disorders can arise throughout the lifespan. Caution should be exercised when prescribing fingolimod and natalizumab to patients with multiple sclerosis who are of childbearing potential because of the risk of disease rebound when they are discontinued. OnabotulinumtoxinA is considered safe in pregnancy and lactation based on long-term observational data. Hypertensive disorders of pregnancy are associated with higher subsequent cerebrovascular risk, likely via multiple mechanisms.

ESSENTIAL POINTS

Neurologic disorders may present in a variety of obstetric and gynecologic contexts, with meaningful implications for recognition and treatment. These interactions must be considered when treating women with neurologic conditions.

CGRP physiology, pharmacology, and therapeutic targets: migraine and beyond

Calcitonin gene-related peptide (CGRP) is a neuropeptide with diverse physiological functions. Its two isoforms (α and β) are widely expressed throughout the body in sensory neurons as well as in other cell types, such as motor neurons and neuroendocrine cells. CGRP acts via at least two G protein-coupled receptors that form unusual complexes with receptor activity-modifying proteins. These are the CGRP receptor and the AMY1 receptor; in rodents, additional receptors come into play. Although CGRP is known to produce many effects, the precise molecular identity of the receptor(s) that mediates CGRP effects is seldom clear. Despite the many enigmas still in CGRP biology, therapeutics that target the CGRP axis to treat or prevent migraine are a bench-to-bedside success story. This review provides a contextual background on the regulation and sites of CGRP expression and CGRP receptor pharmacology. The physiological actions of CGRP in the nervous system are discussed, along with updates on CGRP actions in the cardiovascular, pulmonary, gastrointestinal, immune, hematopoietic, and reproductive systems and metabolic effects of CGRP in muscle and adipose tissues. We cover how CGRP in these systems is associated with disease states, most notably migraine. In this context, we discuss how CGRP actions in both the peripheral and central nervous systems provide a basis for therapeutic targeting of CGRP in migraine. Finally, we highlight potentially fertile ground for the development of additional therapeutics and combinatorial strategies that could be designed to modulate CGRP signaling for migraine and other diseases.

Medication adherence in patients with cluster headache and migraine: an online survey

To examine factors for adherent and non-adherent behavior in patients with cluster headache and migraine. Adults with cluster headache or migraine were included in this anonymous online survey using a questionnaire accessed via homepages of headache support groups. Medication adherence in preventive treatment was measured with the Medication Adherence Report Scale (MARS-D). Factors for non-adherent behavior were examined (subjective socioeconomic status, psychological comorbidities, self-efficacy, coping, side effects, expectations of treatment, information on medical treatment, and trust in the physician/treatment concept). 200 participants (n = 58 with cluster headache, n = 142 with migraine) were included. The rate of medication adherence in preventive treatment was 32.8% for participants with cluster headache and 20.4% for migraine. The most common reasons for low adherence in participants with cluster headache were altering the prescribed medication dose (34%) or taking less than instructed (14%), which was mostly due to insufficient benefit from the medication or side effects. Positive expectations of medical treatment (p ≤ 0.05) correlated significantly with adherent behavior in cluster headache. Furthermore, the adherence-promoting factors coping and self-efficacy were more pronounced in patients with cluster headache than in those with migraine (p < 0.05). This study is the first to comprehensively investigate medication adherence and factors influencing adherent/non-adherent behavior in patients with cluster headache. Patients with cluster headache had similar adherence levels to patients with migraine, but had higher resources of adherence-promoting factors.

Galcanezumab effects on incidence of headache after occurrence of triggers, premonitory symptoms, and aura in responders, non-responders, super-responders, and super non-responders

BACKGROUND

The goal of this observational, open-label, cohort study was to determine whether prophylactic migraine treatment with galcanezumab, a peripherally acting drug, alters the incidence of premonitory symptoms, and/or occurrence of headache after exposure to triggers or aura episodes in treatment-responders (≥ 50% reduction in monthly migraine days [MMD]), super-responders (≥ 70%), non-responders (< 50%) and super non-responders (< 30%).

METHODS

Participants were administered electronic daily headache diaries to document migraine days and associated symptoms one month before and during the three months of treatment. Questionnaires were used to identify conscious prodromal and trigger events that were followed by headache prior to vs. after 3 months of treatment.

RESULTS

After 3 months of galcanezumab treatment, (a) the incidence of premonitory symptoms that were followed by headache decreased by 48% in the 27 responders vs. 28% in the 19 non-responders, and by 50% in the 11 super-responders vs. 12% in the 8 super non-responders; (b) the incidence of visual and sensory aura that were followed by headache was reduced in responders, non-responders, and super-responders, but not in super non-responders; (c) the number of triggers followed by headache decreased by 38% in responders vs. 13% in non-responders, and by 31% in super-responders vs. 4% in super non-responders; and (d) some premonitory symptoms (e.g., cognitive impairment, irritability, fatigue) and triggers (e.g., stress, sleeping too little, bright light, aura) were followed by headache only in super non-responders.

CONCLUSIONS

Mechanistically, these findings suggest that even a mild decrease in migraine frequency is sufficient to partially reverse the excitability and responsivity of neurons involved in the generation of certain triggers and potentially premonitory symptoms of migraine.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT04271202. Registration date: February 10, 2020.

Management of Trigeminal Autonomic Cephalalgias Including Chronic Cluster: A Review

Importance

Trigeminal autonomic cephalalgias (TACs) comprise a unique collection of primary headache disorders characterized by moderate or severe unilateral pain, localized in in the area of distribution of the first branch of the trigeminal nerve, accompanied by cranial autonomic symptoms and signs. Most TACs are rare diseases, which hampers the possibility of performing randomized clinical trials and large studies. Therefore, knowledge of treatment efficacy must be based only on observational studies, rare disease registries, and case reports, where real-world data and evidence play an important role in health care decisions.

Observations

Chronic cluster headache is the most common of these disorders, and the literature offers some evidence from randomized clinical trials to support the use of pharmacologic and neurostimulation treatments. Galcanezumab, a monoclonal antibody targeting the calcitonin gene-related peptide, was not effective at 3 months in a randomized clinical trial but showed efficacy at 12 months in a large case series. For the other TACs (ie, paroxysmal hemicrania, hemicrania continua, short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing, and short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms), only case reports and case series are available to guide physicians in everyday management.

Conclusions and Relevance

The accumulation of epidemiologic, pathophysiologic, natural history knowledge, and data from case series and small controlled trials, especially over the past 20 years from investigators around the world, has added to the previously limited evidence and has helped advance and inform the treatment approach to rare TACs, which can be extremely challenging for clinicians.

Pre-treatment non-ictal cephalic allodynia identifies responders to prophylactic treatment of chronic and episodic migraine patients with galcanezumab: A prospective quantitative sensory testing study (NCT04271202)

BACKGROUND

Migraine is a complex neurological disorder involving generalized abnormalities in processing sensory information. Adopting evidence that central sensitization imposes major hurdles in the treatment of migraine, we hypothesized that it is the non-ictal (rather than ictal) allodynia that may determine the outcome of migraine prevention with peripherally-acting drugs.

METHODS

To test this hypothesis, we used Quantitative Sensory Testing to determine whether it is possible to identify a patient's response to prophylactic treatment with galcanezumab based on presence/absence of cephalic and/or extracephalic allodynia during the pre-treatment non-ictal phase of migraine.

RESULTS

Using strict criteria for allodynia (heat 32-40°C, cold 32-20°C, mechanical <60 g), we report that (a) the incidence of pre-treatment non-ictal cephalic allodynia was 21% in the 24 responders (>50% decrease in monthly migraine days) and 85% in the 19 non-responders; (b) the incidence of non-ictal extracephalic allodynia distinguishes responders from non-responders less accurately; and that (c) the incidence of non-ictal cephalic allodynia was similar in the chronic migraine and high-frequency episodic migraine groups.

CONCLUSIONS

Clinically, the findings suggest that presence/absence of non-ictal allodynia can be used to identify galcanezumab responders with nearly 80% accuracy and galcanezumab non-responders with nearly 85% accuracy. Mechanistically, the presence of non-ictal allodynia (reflecting a state of activity-independent central sensitization) in both chronic migraine and high-frequency episodic migraine patients raises the possibility that the state of non-ictal allodynia may be attributed to physiological properties of central trigeminovascular neurons that are due to the genetic load of the individual patient rather than their migraine frequency.

Preventive treatment of refractory chronic cluster headache: systematic review and meta-analysis

BACKGROUND

Preventive treatment for refractory chronic cluster headache (rCCH) is challenging and many therapies have been tried.

OBJECTIVE

To study what could be considered the therapy of choice in rCCH through a systematic review and meta-analysis.

METHODS

This review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The protocol was registered in PROSPERO (ID CRD42021290983). A systematic search was performed in MEDLINE, Embase, Cochrane, clinicaltrials.gov, and the WHO's-International-Clinical-Trials-Registry-Platform. Studies on the preventive treatment for rCCH as defined by the European Headache Federation consensus statement were included. A meta-analysis of the pooled response rate was conducted for the different therapies.

RESULTS

Of 336 results, 45 were eligible for inclusion. Most articles studied the effect of neuromodulation as a preventive treatment for rCCH. The most studied neuromodulation technique was occipital nerve stimulation (ONS), with a pooled response rate in the meta-analysis of 57.3% (95% CI 0.481-0.665). Deep brain stimulation (DBS) was the second most studied treatment with a pooled response rate of 77.0% (95% CI 0.594-0.957). DBS results were more heterogeneous than ONS, which could be related to the different stimulation targets in DBS studies, and reported more serious adverse events than in ONS studies. The remaining therapies (anti-CGRP pathway drugs, warfarin, ketamine-magnesium infusions, serial occipital nerve blocks, clomiphene, onabotulinum toxin A, ketogenic diet, sphenopalatine ganglion radiofrequency or stimulation, vagus nerve stimulation, percutaneous bioelectric current stimulation, upper cervical cord stimulation, and vidian neurectomy) present weaker results or have less quality of evidence.

CONCLUSIONS

The results of this systematic review and meta-analysis suggest that ONS could be the first therapeutic strategy for patients with rCCH based on the current evidence.

Clinical Profile of Chronic Cluster Headaches in a Regional Headache Center in Japan

Objective Little is known about the prevalence and characteristics of chronic cluster headache (CCH) in Japan. We therefore characterized the clinical profile of CCH in Japan by surveying patients with CCH who were registered at a Japanese regional headache center. We also reviewed the existing literature for the prevalence and clinical characteristics of CCH reported in various populations. Methods In this single-center retrospective study, we assessed consecutive patients with cluster headache (CH) who visited a regional tertiary headache center between February 2011 and July 2020. They were treated following the Clinical Practice Guideline for Chronic Headache 2013. We compared their demographic characteristics and clinical features according to the CCH onset pattern (primary vs. secondary). Results Of 420 patients with CH, 19 (4.2%) had CCH (9 primary and 10 secondary). The incidence of CCH in Japan is relatively low compared to that in Western countries but is comparable to that in other Asian countries. CCH showed a higher predominance of men than women. Compared to primary CCH, secondary CCH included a higher proportion of current smokers and older patients during clinic visits. Subcutaneous sumatriptan and oxygen inhalation were the most common abortive treatments, and oral prednisolone and verapamil were the most common preventive treatments. Home oxygen therapy was effective in six of seven patients. Only two patients with coexisting migraine received calcitonin gene-related peptide (CGRP)-targeted therapies. Conclusions CCH remains refractory to treatment. Improving treatment outcomes will require maximizing the use of currently available drugs and expanding the use of neuromodulation, nerve block, and CGRP-targeted therapies.

Debate: Are cluster headache and migraine distinct headache disorders?

Cluster headache and migraine are regarded as distinct primary headaches. While cluster headache and migraine differ in multiple aspects such as gender-related and headache specific features (e.g., attack duration and frequency), both show clinical similarities in trigger factors (e.g., alcohol) and treatment response (e.g., triptans). Here, we review the similarities and differences in anatomy and pathophysiology that underlie cluster headache and migraine, discuss whether cluster headache and migraine should indeed be considered as two distinct primary headaches, and propose recommendations for future studies. Video recording of the debate held at the 1st International Conference on Advances in Migraine Sciences (ICAMS 2022, Copenhagen, Denmark) is available at https://www.youtube.com/watch?v=uUimmnDVTTE .

Exploratory investigation of a patient-informed low-dose psilocybin pulse regimen in the suppression of cluster headache: Results from a randomized, double-blind, placebo-controlled trial

OBJECTIVE

Using a patient-informed regimen, we conducted an exploratory randomized, double-blind, placebo-controlled study to systematically investigate the effects of psilocybin in cluster headache.

BACKGROUND

Sustained reductions in cluster headache burden after limited quantities of psilocybin-containing mushrooms are anecdotally reported, although to date there are no controlled studies investigating these effects.

METHODS

Participants were randomized to receive psilocybin (0.143 mg/kg) or placebo (microcrystalline cellulose) in a pulse of three doses, each ~5 days apart. Participants maintained headache diaries starting 2 weeks before and continuing through 8 weeks after the first drug session. A total of 16 participants were randomized to receive experimental drug and 14 were included in the final analysis.

RESULTS

In the 3 weeks after the start of the pulse regimen, the change in cluster attack frequency was 0.03 (95% confidence interval [CI] -2.6 to 2.6) attacks/week with placebo (baseline 8.9 [95% CI 3.8 to 14.0]) and -3.2 (95% CI -8.3 to 1.9) attacks/week with psilocybin (baseline 9.6 [95% CI 5.6 to 13.6]; p = 0.251). Group difference in change from baseline had a moderate effect size (d = 0.69). The effect size was small in episodic participants (d = 0.35) but large in chronic participants (d = 1.25), which remained over the entire 8-week period measured (d = 0.81). Changes in cluster attack frequency were not correlated with the intensity of acute psychotropic effects during psilocybin administration. Psilocybin was well-tolerated without any unexpected or serious adverse events.

CONCLUSIONS

Findings from this initial, exploratory study provide valuable information for the development of larger, more definitive studies. Efficacy outcomes were negative, owing in part to the small number of participants. The separation of acute psychotropic effects and lasting therapeutic effects underscores the need for further investigation into the mechanism(s) of action of psilocybin in headache disorders.

Real-world experience with 240 mg of galcanezumab for the preventive treatment of cluster headache

Background

Galcanezumab of 300 mg monthly is the FDA approved preventive medication for cluster headache (CH) during the cluster period. Compared to the 120 mg galcanezumab syringe for the treatment of migraines, the 100 mg syringe for CH has globally not been as widely available. The aim of our study was to investigate the preventive efficacy and tolerability of two 120 mg galcanezumab doses for episodic CH in clinical practices.

Methods

We evaluated patients with CH who received at least 1 dose of 240 mg (2 prefilled syringe of 120 mg) of galcanezumab in the 3 university hospitals from February 2020 to September 2021. In the patients with episodic CH, the efficacy and safety data of galcanezumab were analyzed regarding to the presence of the conventional preventive therapy at the timing of therapy of galcanezumab. The data of other subtypes of CH were separately described.

Results

In 47 patients with episodic CH, galcanezumab was started median 18 days after the onset of current bout (range 1–62 days) and 4 patients (10.8%) received second dose of galcanezumab. The median time to the first occurrence of 100% reduction from baseline in CH attacks per week after galcanezumab therapy was 17 days (25% to 75% quartile range: 5.0 ~ 29.5) in all patients with episodic CH, 15.5 days (3.8 ~ 22.1) in 36 patients with galcanezumab therapy add-on conventional preventive therapy, 21.0 days (12.0 ~ 31.5) in 11 patients started galcanezumab as initial preventive therapy. Among 33 patients with headache diary, the proportion of patients with 50% or more reduction in weekly CH attacks at week 3 from baseline were 78.8%. There was no significant difference in the proportion of patients with a reduction of at least 50% in weekly frequency of CH attacks at week 3 between 24 patients received galcanezumab therapy add-on conventional preventive therapy and 9 patient who received initial galcanezumab therapy. (83.3%, vs 66.7%, p = 0.36). There were no significant differences in proportion of “very much better or “much better” between 36 patients received galcanezumab therapy add-on conventional preventive therapy and 11 patient who received initial GT (86.1%, vs 63.6%, p = 0.18).

Conclusion

One 240 mg dose of galcanezumab with/without conventional therapy for the prevention of CH is considered effective and safe in clinical practices, as seen in the clinical trial of galcanezumab.

Cranial autonomic symptoms and response to monoclonal antibodies targeting the Calcitonin gene-related peptide pathway: A real-world study

Objective

Cranial autonomic symptoms (CAS), including conjunctival injection, tearing, nasal congestion or rhinorrhea, eyelid edema, miosis or ptosis, and forehead or facial sweating ipsilateral to headache, are often reported by patients with migraine during headache attacks. CAS is a consequence of the activation of the trigeminovascular system, which is the target of monoclonal antibodies acting on the CGRP pathway. Therefore, we hypothesized that patients with CAS might have higher trigeminovascular activation than those without CAS leading to a better response to anti-CGRP treatments.

Methods

We performed a prospective analysis including patients with episodic or chronic migraine treated with anti-CGRP monoclonal antibodies (i.e., erenumab, fremanezumab, and galcanezumab) between 2019 and 2021. The observation period included a 12-week baseline before treatment with anti-CGRP antibodies and a 12-week treatment follow-up. We evaluated the prevalence of CAS in our cohort and compared disease characteristics and treatment response (i.e., 12-week monthly headache days and 0–29, 30–49, 50–74, 75–99, and 100% monthly headache days reduction from baseline) among patients with and without CAS using the χ² test, Kruskal–Wallis test, and Mann–Whitney U-test.

Results

Out of 136 patients, 88 (65%) had CAS. Both patients with and without CAS reported a significant decrease in monthly headache days from baseline. During the 12-week follow-up, the median difference in monthly headache days from baseline was higher in patients with CAS (-10, IQR−15 to−6) than in those without CAS (6, IQR 12 to 3; P = 0.009). However, the proportions of patients with 0 to 29, 30 to 49, 50 to 74, 75 to 99, and 100% response rates did not differ between the two groups.

Conclusions

In our cohort, the presence of CAS was associated with a greater response to monoclonal antibodies targeting the CGRP pathway. CAS could be a clinical marker of trigeminovascular activation and thus be related to a better response to CGRP treatments.

Guidelines of the International Headache Society for Controlled Clinical Trials in Cluster Headache

In 1995, a committee of the International Headache Society developed and published the first edition of the Guidelines for Controlled Trials of Drugs in Cluster Headache. These have not been revised. With the emergence of new medications, neuromodulation devices and trial designs, an updated version of the International Headache Society Guidelines for Controlled Clinical Trials in Cluster Headache is warranted. Given the scarcity of evidence-based data for cluster headache therapies, the update is largely consensus-based, but takes into account lessons learned from recent trials and demands by patients. It is intended to apply to both drug and neuromodulation treatments, with specific proposals for the latter when needed. The primary objective is to propose a template for designing high quality, state-of-the-art, controlled clinical trials of acute and preventive treatments in episodic and chronic cluster headache. The recommendations should not be regarded as dogma and alternative solutions to particular methodological problems should be explored in the future and scientifically validated.

Recent Advances and Updates in Trigeminal Autonomic Cephalalgias

Trigeminal autonomic cephalalgias (TACs) are discrete primary headache disorders, characterized by severe unilateral head pain, typically trigeminal distribution, with ipsilateral cranial autonomic symptoms. The conditions within this group are hemicrania continua, cluster headache, paroxysmal hemicrania, and short-lasting unilateral neuralgiform headache with conjunctival injection and tearing and short-lasting unilateral neuralgiform headache with autonomic symptoms. Several advances have been made in understanding the pathogenesis and evolving treatment options in TACs. This review will outline the advances and updates in each TAC.

CGRP-Targeted Therapy for Episodic and Chronic Cluster Headache

PURPOSE OF REVIEW

Chronic cluster headache (CH) substantially affects patients' quality of life, and treatment remains challenging. The current article reviewed controlled studies for new treatment options targeting calcitonin gene-related peptide (CGRP) or its receptors in CH and discussed the current gaps and future directions for the treatment of chronic CH.

RECENT FINDINGS

Two anti-CGRP monoclonal antibodies (i.e., galcanezumab and fremanezumab) completed randomized-control trials for efficacy for the preventive treatment of episodic and chronic CH. Galcanezumab was effective for preventing episodic CH but not chronic CH. Fremanezumab was ineffective in preventing episodic and chronic CH. Studies for other anti-CGRP monoclonal antibodies and CGRP antagonists are still pending for results. There are no randomized controlled trials for CGRP-targeted therapies that showed efficacy for chronic CH prevention. The different responses to galcanezumab between episodic and chronic CH may be due to the study design, i.e., the allowance of concomitant preventive therapies in the chronic CH study but not in the episodic CH study. Another reason for the discrepancies is the different roles and sensitivity of CGRP in chronic CH.

Long-term open-label safety study of galcanezumab in patients with episodic or chronic cluster headache

BACKGROUND

CGAR, a Phase 3b open-label study, evaluated the long-term safety of galcanezumab in patients with cluster headache who completed one of two Phase 3 double-blind studies in chronic or episodic cluster headache.

METHODS

Patients (N = 164) received galcanezumab 300 mg subcutaneously up to once a month. Primary endpoint was safety, as assessed by treatment-emergent adverse events, serious adverse events, and suicidality. Other endpoints included discontinuation rates, immunogenicity, efficacy as assessed by the Patient Global Impression of Improvement, and health values.

RESULTS

At baseline, mean (standard deviation) age was 48.3 (9.8) years, 75.0% were men, and 85.4% were white. Treatment-emergent adverse events (n = 119 [72.6%]) were mostly mild-to-moderate, with nasopharyngitis the most commonly reported (22.0%). One of 18 serious adverse events was judged as treatment related (constipation). Two patients (1.2%) reported suicidal ideation. Five patients (3.1%) discontinued due to an adverse event. Eight patients were treatment-emergent anti-drug antibody positive, two of whom were not treatment-emergent anti-drug antibody positive in the parent studies. On the Patient Global Impression of Improvement, ≥81% reported their cluster headache status as very much, much, or a little better at Months 1, 6, and 12. Health value scores generally improved from baseline.

CONCLUSIONS

In this open-label study, galcanezumab was generally well tolerated and improved patient-reported cluster headache status.Trial registration number: NCT02797951; https://clinicaltrials.gov/ct2/show/NCT02797951.

Calcitonin Gene-Related Peptide (CGRP)-Targeted Monoclonal Antibodies and Antagonists in Migraine: Current Evidence and Rationale

Calcitonin gene-related peptide (CGRP), a 37 amino-acid neuropeptide found mostly in peptidergic sensory C-fibers, has been suggested to be implicated in the pathogenesis of migraine, which is one of the most common neurological disorders seen in medical practice, affecting almost 16% of the US population. While previously thought to be a vascular condition, migraine attacks are the result of neurogenic inflammation and peripheral/central sensitization through dysfunctional activation of the trigeminovascular system. To date, two classes of therapeutic agents have been developed to interrupt the function of CGRP: CGRP-targeted monoclonal antibodies (mAbs) and small-molecule antagonists (gepants). There are currently four CGRP-targeted mAbs and three gepants that are US Food and Drug Administration (FDA) approved for the treatment of migraine. Multiple phase II and III studies have established the efficacies and tolerability of these treatments. Previously, we reviewed the fundamental role of CGRP in migraine pathogenesis. Here, we discuss in depth the clinical evidence (randomized controlled trials and real-world studies), safety, and tolerability of CGRP-targeted mAbs and gepants for treating migraine.

[Galcanezumab for episodic and chronic cluster headache]

BACKGROUND

Cluster headache (CH) is a highly debilitating headache disorder characterized by frequent attacks of excruciating unilateral pain accompanied by cranial autonomic symptoms. Calcitonin gene-related peptide (CGRP) is implicated in the pathophysiology of CH.

OBJECTIVES

Preventive efficacy and tolerability of the anti-CGRP antibody galcanezumab in patients with episodic (eCH) and chronic CH (cCH). Review of the study results and the challenges in developing drugs for the preventive treatment of CH.

MATERIALS AND METHODS

In two international multicenter phase III trials galcanezumab 300 mg given subcutaneously every 4 weeks was compared with placebo. The double-blind study period (8 weeks in eCH, 12 weeks in cCK) was preceded by a baseline period in both trials. The primary endpoint was the reduction in weekly attack frequency.

RESULTS

In the eCH trial, 106 patients were randomized to either galcanezumab (n = 49) or placebo (n = 57). The mean weekly attack frequency during the first 3 weeks decreased by 52% in the galcanezumab group compared with 27% in the placebo group (p = 0.036). In the cCH trial, 237 patients were randomized to galcanezumab (n = 117) or placebo (n = 120). The primary endpoint was not met in this study. The reduction in mean weekly attack rate was 5.4 with galcanezumab versus 4.6 with placebo (p = 0.334). Galcanezumab was well tolerated in both studies.

CONCLUSIONS

Galcanezumab had a significant effect in the prevention of eCH attacks but not in cCH. Possible reasons for this discrepancy are discussed.

Challenges and complexities in designing cluster headache prevention clinical trials: A narrative review

Objective

To provide a review of challenges in clinical trials for the preventive treatment of cluster headache (CH) and highlight considerations for future studies.

Background

Current guidelines for preventive treatment of CH are largely based on off‐label therapies supported by a limited number of small randomized controlled trials. Guidelines for clinical trial design for CH treatments from the International Headache Society were last issued in 1995.

Methods/Results

Randomized controlled clinical trials were identified in the European and/or United States clinical trial registries with a search term of “cluster headache,” and manually reviewed. Cumulatively, there were 27 unique placebo‐controlled prevention trials for episodic and/or chronic CH, of which 12 were either ongoing, not yet recruiting, or the status was unknown. Of the remaining 15 trials, 5 were terminated early and 7 of the 10 completed trials enrolled fewer patients than planned or did not report the planned sample size. A systematic search of PubMed was also utilized to identify published manuscripts reporting results from placebo‐controlled preventive trials of CH. This search yielded 16 publications, of which 7 were registered. Through critical review of trial data and published manuscripts, challenges and complexities encountered in clinical trials for the preventive treatment of CH were identified. For example, the excruciating pain associated with CH demands a suitably limited baseline duration, rapid treatment efficacy onset, and poses a specific issue regarding duration of investigational treatment period and length of exposure to placebo. In episodic CH, spontaneous remission as part of natural history, and the unpredictability and irregularity of cluster periods across patients present additional key challenges.

Conclusions

Optimal CH trial design should balance sound methodology to demonstrate efficacy of a potential treatment with patient needs and the natural history of the disease, including unique outcome measures and endpoint timings for chronic versus episodic CH.

Recent advances in the diagnosis and management of cluster headache

Cluster headache, a primary headache disorder, consists of short (15-180 minutes), frequent (up to eight a day), unilateral attacks of facial pain with associated ipsilateral autonomic features and restlessness. The attacks are suspected to be one of the most painful human experiences, and the disorder is associated with a high rate of suicidal ideation. Proper diagnosis is key, as some of the most effective treatments, such as high flow oxygen gas, are rarely used in other headache disorders. Yet diagnostic delay is typically years for this disorder, as it is often confused with migraine and trigeminal neuralgia, and secondary causes may be overlooked. This review covers the clinical, pathophysiologic, and therapeutic features of cluster headache. Recent updates in diagnosis include the redefinition of chronic cluster headache (remission periods lasting less than three months instead of the previous one month), and recent advances in management include new treatments for episodic cluster headache (galcanezumab and non-invasive vagus nerve stimulation).

Comparative Impact of Pharmacological Therapies on Cluster Headache Management: A Systematic Review and Network Meta-Analysis

It is important to find effective and safe pharmacological options for managing cluster headache (CH) because there is limited evidence from studies supporting the general efficacy and safety of pharmacological therapies. This systematic review and network meta-analysis (NMA) analyzed published randomized controlled trials (RCTs) to evaluate the efficacy and safety of pharmacological treatments in patients with CH. The PubMed and Embase databases were searched to identify RCTs that evaluated the efficacy and safety of pharmacological treatments for CH. Efficacy outcomes included frequency and duration of attacks, pain-free rate, and the use of rescue agents. Safety outcomes were evaluated based on the number of patients who experienced adverse events. A total of 23 studies were included in the analysis. The frequency of attacks was reduced (mean difference (MD) = −1.05, 95% confidence interval (CI) = −1.62 to −0.47; p = 0.0004), and the pain-free rate was increased (odds ratio (OR) = 3.89, 95% CI = 2.76−5.48; p < 0.00001) in the pharmacological treatment group, with a lower frequency of rescue agent use than the placebo group. Preventive, acute, and triptan or non-triptan therapies did not show significant differences in efficacy (p > 0.05). In the NMA, different results were shown among the interventions; for example, zolmitriptan 5 mg was more effective than zolmitriptan 10 mg in the pain-free outcome (OR = 0.40, 95% CI = 0.19−0.82; p < 0.05). Pharmacological treatment was shown to be more effective than placebo to manage CH with differences among types of therapies and individual interventions, and it was consistently shown to be associated with the development of adverse events. Thus, individualized therapy approaches should be applied to treat CH in real-world practice.

Effects of acute and preventive therapies for episodic and chronic cluster headache: A scoping review of the literature

BACKGROUND

Cluster headache is the most common primary headache disorder of the trigeminal autonomic cephalalgias, and it is highly disabling.

OBJECTIVE

We undertake a scoping review to characterize therapies to prevent and acutely treat cluster headache, characterize trial methodology utilized in studies, and recommend future trial "good practices." We also assess homogeneity of studies and feasibility for future network meta-analyses (NMAs) to compare acute and preventive treatments for cluster headache.

METHODS

A priori protocol for this scoping review was registered and available on Open Science Forum. We sought studies that enrolled adult patients with cluster headache as identified by accepted diagnostic criteria. Both randomized controlled trials (RCTs) and observational studies (with a control group) were included. The interventions of interest were medications, procedures, devices, surgeries, and behavioral/psychological interventions, whereas comparators of interest were placebo, sham, or other active treatments. Outcomes were predefined; however, we did not exclude studies lacking these outcomes. A systemic search was conducted in Ovid Medline, Embase, and Cochrane. We performed a targeted search for conference abstracts from journals prominent in the field.

RESULTS

We identified 56 studies: 45 RCTs, four studies only available in clinical trial registries, and seven observational studies. Of the 45 RCTs, 20 focused on acute therapies and 25 on preventive therapies. Overall, we determined that it is feasible to pursue a NMA for acute therapy focusing on 15 or 30-min headache reduction for acute trials, as we identified 11 trials in the combined population of patients with either episodic or chronic cluster headache (2 trials in populations with chronic cluster headache were also found). For preventive therapy of cluster headache, we identified trials with common outcomes that may be considered for NMA, however, as these trials had differences in treatment effect modifiers that could not be corrected, NMAs appear infeasible for this indication. We identified new studies looking at noninvasive vagal nerve stimulation, sphenopalatine ganglion stimulation, prednisone, and oxygen published since the most recent systematic review in the field, although these acute treatments were previously identified as effective. However, for calcitonin gene-related peptide (CGRP) monoclonal antibodies, galcanezumab demonstrated effectiveness in episodic cluster headache, but a lack of effectiveness in chronic cluster headache, and fremanezumab was not effective for episodic nor chronic cluster headache. This finding highlights that CGRP monoclonal antibodies may not show a class effect in cluster headache prevention and need to be considered individually.

CONCLUSIONS

We describe the treatment landscape of cluster headache for both acute and preventive treatments. Last, we present the NMAs we will undertake in acute therapies of cluster headache.

History of cluster headache

Objective:

To summarise the history of cluster headache evolving concepts and growing insights.

Background:

Excruciating pain, activation of the parasympathetic nervous system, and circadian rhythmicity characterise cluster headache attacks.

Results:

We find the oldest descriptions of patients suffering from the disorder in case reports of the 17th and 18th centuries. Only in the 19th and early 20th centuries did physicians start hypothesizing its cause. Initially, many researchers suspected the origin of the pain in peripheral nerves or blood vessels. However, eventually, they understood that the cause of the disease lies in the brain. In 1998, Positron emission tomography studies revealed increased activity of the posterior hypothalamus, whose role remains incompletely understood. Only recently have researchers realised that being diseased implies more than dysfunction. Recent studies analysed the consequences of cluster headache for each patient. Many struggle to deal with the disorder even in the absence of pain.

Conclusion:

Physicians have been aware of this type of pain for at least 300 years. Only when researchers studied pathological anatomy and physiology did knowledge accrue. A more comprehensive picture of the disease severity emerged when they also considered its consequences.

Psychedelics in the Treatment of Headache and Chronic Pain Disorders

The therapeutic potential of psychedelics in headache and chronic pain disorders is documented over decades of anecdotal and early investigational reports, which have paved the way for the first controlled studies of psilocybin and lysergic acid diethylamide (LSD) in these disorders. The reported lasting clinical effects after limited dosing with psychedelics present a novel means for disease management, but considerable further study will be required to address disease-specific treatments, uncover mechanism(s) of action, and verify safety. In this chapter, these topics are reviewed with particular attention to the neurobiological systems that offer potential sources of psychedelics' unique clinical effects in headache and pain.

Next generation antibody-based therapies in neurology

Antibody (Ab)-based therapeutics are now standard in the treatment of neuroinflammatory diseases, and the spectrum of neurological diseases targeted by those approaches continues to grow. The efficacy of Ab-based drug-platforms is largely determined by the specificity-conferring antigen-binding fragment (Fab) and the crystallizable fragment (Fc) driving antibody function. The latter provides specific instructions to the immune system by interacting with cellular Fc receptors and complement components. Extensive engineering efforts enabled tuning of Fc functions to modulate effector functions and to prolong or reduce Ab serum half-lives. Technologies that improve bioavailability of Ab-based treatment platforms within the central nervous system parenchyma are being developed and could invigorate drug discovery for a number of brain diseases for which current therapeutic options are limited. These powerful approaches are currently being tested in clinical trials or have been successfully translated into the clinic. Here, we review recent developments in the design and implementation of Ab-based treatment modalities in neurological diseases.

Drug Treatment of Cluster Headache

Cluster headache belongs to the group of trigeminal autonomic headaches. This review summarizes drug therapy of cluster attacks and prophylactic treatment. Neurostimulation methods are not addressed. The therapy for acute cluster attacks includes inhalation of 100% oxygen, subcutaneous administration of sumatriptan, and intranasal application of sumatriptan or zolmitriptan. Bridging therapy, which is used until oral prophylactic therapy is effective, is performed either with oral prednisolone or with a pharmacological block of the major occipital nerves. Best documented drugs for preventive treatment of cluster headache are verapamil and lithium, and possibly effective drugs are gabapentin, topiramate, divalproex sodium, and melatonin. The efficacy of monoclonal antibodies to the calcitonin gene-related peptide so far has been only demonstrated for episodic cluster headache. Several drug therapies are being investigated including ketamine, onabotulinumtoxinA, lysergic acid, and sodium oxybate.