Monoclonal antibodies blocking CGRP transmission: An update on their added value in migraine prevention

Observational Retrospective Study in Patients Treated with Galcanezumab as Preventive Treatment for Migraine: The ORYGAM Study

INTRODUCTION

The efficacy of galcanezumab has been demonstrated in randomized controlled trials, but evidence about its use under clinical practice conditions is still limited. This study aimed to describe the characteristics of the patients treated with galcanezumab in routine clinical practice in Spain as well as treatment patterns, persistence, and effectiveness.

METHODS

A retrospective chart review study was carried out in six hospitals. Information of adults with migraine, who started treatment with galcanezumab between November 2019 and September 2021, was analyzed until end or loss of follow-up. Continuous variables were described as mean (standard deviation, SD) and median (interquartile range, IQR), and categorical variables as frequency and percentages. Persistence to treatment was estimated using Kaplan-Meier analysis.

RESULTS

A total of 314 patients were analyzed over median follow-up period of 17.5 months (13.8-20.7), with a mean age of 46.3 (12.6), 85% women, 80.6% chronic migraine, and reporting a mean of monthly migraine days of 16.7 (7.8). Overall, 72.9% had comorbid conditions, with anxiety and depression disorders being the most frequent. More than 60% had received ≥ 6 previous preventive drugs, the most common being antiepileptics, antidepressants, and botulinum toxin (95.2%, 89.8% and 84.1%, respectively). Overall, 60.3% of the patients with other preventive treatments maintained them after galcanezumab initiation. The median time on galcanezumab was 14.6 months (9.4-22.8); 95.7%, 82.0%, 76.2% and 59.8% of patients were persistent to treatment at 3, 6, 9 and 12 months, respectively. Of the patients who discontinued (151: 48.1%), 57.6% were due to lack of effectiveness and 31.1% were due to improvement in migraine. The average reduction of monthly migraine days at 3, 6, 9 and 12 months was 7.9 (7.2), 9.1 (7.5), 8.8 (6.6) and 9.0 (6.9) days, respectively.

CONCLUSIONS

In real clinical practice, galcanezumab is an effective treatment and has a high persistence in patients with migraine, mostly chronic and with multiple use of previous preventive treatments.

Real-world effectiveness of Anti-CGRP monoclonal antibodies compared to OnabotulinumtoxinA (RAMO) in chronic migraine: a retrospective, observational, multicenter, cohort study

BACKGROUND

Chronic migraine (CM) is a disabling condition with high prevalence in the general population. Until the recent approval of monoclonal antibodies targeting the calcitonin gene-related peptide (Anti-CGRP mAbs), OnabotulinumtoxinA (BoNT-A) was the only treatment specifically approved for CM prophylaxis. Direct comparisons between the two treatments are not available so far.

METHODS

We performed an observational, retrospective, multicenter study in Italy to compare the real-world effectiveness of Anti-CGRP mAbs and BoNT-A. Patients with CM who had received either treatment according to Italian prescribing regulations were extracted from available clinical databases. Efficacy outcomes included the change from baseline in monthly headache days (MHD), MIgraine Disability ASsessment test (MIDAS), and monthly acute medications (MAM) evaluated at 6 and 12 months of follow-up. The primary outcome was MHD change from baseline at 12 months. Safety outcomes included serious adverse events (SAE) and treatment discontinuation. Unadjusted and adjusted models were used for the analyses.

RESULTS

Two hundred sixteen potentially eligible patients were screened; 183 (86 Anti-CGRP mAbs; 97 BoNT-A) were included. One hundred seventy-one (80 Anti-CGRP mAbs; 91 BoNT-A) and 154 (69 Anti-CGRP mAbs; 85 BoNT-A) patients were included in the efficacy analysis at 6 and 12 months of follow-up, respectively. Anti-CGRP mAbs and BoNT-A both resulted in a mean MHD reduction at 6 (-11.5 and -7.2 days, respectively; unadjusted mean difference -4.3; 95%CI -6.6 to -2.0; p = 0.0003) and 12 months (-11.9 and -7.6, respectively; unadjusted mean difference -4.4; 95%CI -6.8 to -2.0; p = 0.0002) of follow-up. Similar results were observed after adjusting for baseline confounders. Anti-CGRP mAbs showed a significant MIDAS (-31.7 and -19.2 points, p = 0.0001 and p = 0.0296, respectively) and MAM reduction (-5.1 and -3.1 administrations, p = 0.0023 and p = 0.0574, respectively) compared to BoNT-A at 6 and 12 months. No SAEs were reported. One patient receiving fremanezumab discontinued treatment due to arthralgia. Treatment discontinuations, mainly for inefficacy, were comparable.

CONCLUSION

Both Anti-CGRP mAbs and BoNT-A were effective in CM patients with Anti-CGRP mAbs presenting higher effect magnitude, with comparable safety. Still, BoNT-A remains a valuable option for CM patients with contraindications to Anti-CGRP mAbs or for frail categories who are candidates to local therapy with limited risk of systemic administration.

Exploring the Therapeutic Potential of Quadripulse rTMS over the Visual Cortex: A Proof-of-Concept Study in Healthy Volunteers and Chronic Migraine Patients with Medication Overuse Headache

In chronic migraine with medication overuse (CM-MOH), sensitization of visual cortices is reflected by (i) increased amplitude of stimulus-evoked responses and (ii) habituation deficit during repetitive stimulation. Both abnormalities might be mitigated by inhibitory transcranial neurostimulation. Here, we tested an inhibitory quadripulse repetitive transcranial magnetic stimulation (rTMS-QPI) protocol to decrease durably visual cortex excitability in healthy subjects (HS) and explored its therapeutic potential in CM-MOH patients. Pattern-reversal visual evoked potentials (VEP) were used as biomarkers of effect and recorded before (T1), immediately after (T2), and 3 h after stimulation (T3). In HS, rTMS-QPI durably decreased the VEP 1st block amplitude (p < 0.05) and its habituation (p < 0.05). These changes were more pronounced for the P1N2 component that was modified already at T2 up to T3, while for N1P1 they were significant only at T3. An excitatory stimulation protocol (rTMS-QPE) tended to have an opposite effect, restricted to P1N2. In 12 CM-MOH patients, during a four-week treatment (2 sessions/week), rTMS-QPI significantly reduced monthly headache days (p < 0.01). In patients reversing from CM-MOH to episodic migraine (n = 6), VEP habituation significantly improved after treatment (p = 0.005). rTMS-QPI durably decreases visual cortex responsivity in healthy subjects. In a proof-of-concept study of CM-MOH patients, rTMS-QPI also has beneficial clinical and electrophysiological effects, but sham-controlled trials are needed.

Characteristics associated with response to subcutaneously administered anti-CGRP monoclonal antibody medications in a real-world community cohort of persons living with migraine: A retrospective clinical and genetic study

OBJECTIVE

To evaluate response to anti-calcitonin gene-related peptide (CGRP) migraine preventives in a real-world community cohort of persons living with migraine and to identify clinical and genetic characteristics associated with efficacious response.

BACKGROUND

Erenumab-aooeb, fremanezumab-vrfm, and galcanezumab-gnlm target CGRP or its receptor; however, many patients are non-responsive.

METHODS

In this retrospective clinical and genetic study, we identified 1077 adult patients who satisfied the International Classification of Headache Disorders, 3rd edition, criteria for migraine without aura, migraine with aura, or chronic migraine and who were prescribed an anti-CGRP migraine preventive between May 2018 and May 2021. Screening of 558 patients identified 289 with data at baseline and first follow-up visits; data were available for 161 patients at a second follow-up visit. The primary outcome was migraine days per month (MDM). In 198 genotyped patients, we evaluated associations between responders (i.e., patients with ≥50% reduction in MDM at follow-up) and genes involved in CGRP signaling or pharmacological response, and genetic and polygenic risk scores.

RESULTS

The median time to first follow-up was 4.4 (0.9-22) months after preventive start. At the second follow-up, 5.7 (0.9-13) months later, 145 patients had continued on the same preventive. Preventives had strong, persistent effects in reducing MDM in responders (follow-up 1: η2  = 0.26, follow-up 2: η2  = 0.22). At the first but not second follow-up: galcanezumab had a larger effect than erenumab, while no difference was seen at either follow-up between galcanezumab and fremanezumab or fremanezumab and erenumab. The decrease in MDM at follow-up was generally proportional to baseline MDM, larger in females, and increased with months on medication. At the first follow-up only, patients with prior hospitalization for migraine or who had not responded to more preventive regimens had a smaller decrease in MDM. Reasons for stopping or switching a preventive varied between medications and were often related to cost and insurance coverage. At both follow-ups, patient tolerance (1: 92.2% [262/284]; 2: 95.2% [141/145]) and continued use (1: 77.5% [224/289]; 2: 80.6% [116/145]) were high and similar across preventives. Response consistency (always non-responders: 31.7% [46/145]; always responders: 56.5% [82/145], and one-time only responders: 11.7% [17/145]) was also similar across preventives. Non-responder status had nominally significant associations with rs12615320-G in RAMP1 (odds ratio [95% confidence interval]: 4.7 [1.5, 14.7]), and rs4680-A in COMT (0.6[0.4, 0.9]). Non-responders had a lower mean genetic risk score than responders (1.0 vs. 1.1; t(df) = -1.75(174.84), p = 0.041), and the fraction of responders increased with genetic and polygenic risk score percentile.

CONCLUSIONS

In this real-world setting, anti-CGRP preventives reduced MDM persistently and had similar and large effect sizes on MDM reduction; however, clinical and genetic factors influenced response.

Effectiveness and Safety of Eptinezumab in Episodic and Chronic Migraine Headache in the UAE: A Retrospective Study

INTRODUCTION

Eptinezumab is a humanized IgG1 immunoglobulin monoclonal antibody administered intravenously as a preventative migraine treatment. Previously conducted randomized, double-blind, placebo-controlled trials exhibited significant reductions in monthly migraine frequency among adults experiencing episodic and chronic migraine. The present study seeks to expand upon the current findings and to evaluate eptinezumab's efficacy as a preventative treatment for chronic and episodic migraine patients in the United Arab Emirates. This study is intended to represent the first real-world evidence and will hopefully serve as a valuable complement to the existing literature on the subject.

METHODS

This was a retrospective exploratory study. The participants included within the study were adult (≥ 18 years) patients diagnosed with either episodic or chronic migraine. Patients were categorized according to their history of previous preventative treatment failure. For the final assessment of treatment efficacy, we included only patients with a minimum of 6 months of clinical follow-up data. Patients were assessed at baseline for their monthly migraine frequency and assessed again at months 3 and 6. The primary objective was to evaluate the efficacy of eptinezumab in reducing migraine frequency among chronic and episodic migraine patients.

RESULTS

A total of 100 participants were identified, of whom 53 completed the study protocol at month 6. Of the total, 40 (75.47%) were female, 46 (86.79%) were Emirati locals, and 16 (30.19%) were pharmaceutically naïve, having never tried any prior preventative therapy. Additionally, 25 (47.17%) patients met the criteria for chronic migraine (CM), whereas the remaining 28 (52.83%) were diagnosed with episodic migraine (EM). The baseline monthly migraine frequency (MMD) was 12.23 (4.97) days across all participants, 15.56 (3.97) for CM patients, and 9.25 (3.76) for EM patients; by month 6, these frequencies reduced to 3.66 (4.21), 4.76 (5.32), and 2.68 (2.61), respectively. Overall, 58.49% of those enrolled experienced > 75% reduction in MMD frequency by month 6.

CONCLUSION

Patients enrolled in this trial experienced clinically significant reductions in MMD by month 6. Eptinezumab was well tolerated and with one AE of significance that led to discontinuation from the study.

Efficacy and Safety of Anti-calcitonin Gene-Related Peptide (CGRP) Monoclonal Antibodies in Preventing Migraines: A Systematic Review

The neuropeptide calcitonin gene-related peptide (CGRP) is an essential pathophysiological treatment for migraines. A unique class of medications called CGRP monoclonal antibodies target CGRP and its receptor and have demonstrated promising benefits in the treatment and prevention of migraines. This study sought to identify and assess the quality of existing systematic reviews about the effectiveness of CGRP antibodies for preventing migraines, as well as systematically review and synthesize the evidence on these topics. This included the four Food and Drug Administration (FDA)-approved medications erenumab, galcanezumab, fremanezumab, and eptinezumab. The effectiveness and safety of these monoclonal antibodies in preventing migraines should also be examined in light of patient characteristics, and any gaps in the body of knowledge should be noted in order to suggest new lines of investigation. Data gathering included a thorough search of internet databases (PubMed, Cochrane Library, Web of Science, and Scopus) for relevant research released between 2018 and 2023. The findings imply that CGRP monoclonal antibodies are efficient and secure for preventing migraines and may be considered a first-line alternative for treating migraines and drug misuse. The results further imply that combination treatment with CGRP antibodies and onabotulinumtoxinA may enhance the prevention of migraine in adults. With suggestions for more studies to find and address these variables, the significance of genetic and epigenetic factors in the progression of pediatric patients' acute postoperative pain to chronic postsurgical pain is underlined. All four anti-CGRP monoclonal antibodies, erenumab, fremanezumab, galcanezumab, and eptinezumab, were shown to be safe and effective for the prevention of migraine when the research additionally looked at their individual effectiveness and safety. Additionally, the study discovered considerable variances in effectiveness amongst various groups. However, further investigation is required to establish the best time and dosage and the effect of patient characteristics on the effectiveness and safety of these medications.

Treatment pattern and health care resource utilization for Taiwanese patients with migraine: a population-based study

Objectives

Given the substantial disease burden, appropriate and effective management of migraine is a public health priority. To gain insights into real-world migraine management practices in Taiwan, current treatment patterns, costs, and health care resource use were assessed.

Methods

This was a retrospective, longitudinal study using the Taiwan National Health Insurance Research Database. Included patients had an initial diagnosis of migraine (defined using International Classification of Diseases codes) between 1 January 2013 and 31 December 2017. Data analyzed included demographics; the use, number, and type of acute and preventive medications; and drug and medical services costs. Data were stratified according to migraine type (chronic [CM] or episodic [EM] migraine).

Results

A total of 312,718 patients were included in the analyses: 53,992 (17.3%) had CM and 258,726 (82.7%) had EM. Most patients (81.7%) had used acute and/or preventive medications; acute medications used more frequently than preventive medications (78.0% vs. 20.2%). Acute medications were used by 81.6 and 77.3% of patients with CM and EM, respectively. Commonly used acute medications were acetaminophen (68.8%), ergots (49.4%), and non-steroidal anti-inflammatory drugs (38.4%); the use of triptans (6.0%), tramadol (3.1%), and other opioids (0.2%) was less common. A total of 28.6 and 18.5% of patients with CM and EM, respectively, used preventive medications. Flunarizine (68.9%), propranolol (40.7%), and topiramate (16.0%) were the most commonly used preventive medications. Most patients had used 1-2 acute or preventive medications, with the use of ≥3 acute or preventive medications more common in patients with CM than EM. Average total medical cost per annum was 4,169 New Taiwan Dollars (NTDs) per CM patient and 2,928 NTDs per EM patient, with CM patients having higher costs associated with medical service utilization and acute medication use.

Conclusion

These real-world data suggest unmet needs for Taiwanese patients with migraine, including under-utilization of preventive medications and greater costs and health care resource use for patients with CM versus EM. These findings provide important information on treatment patterns, cost, and health care resource use for patients with migraine in Taiwan.

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.

Inhibiting neuronal AC1 for treating anxiety and headache in the animal model of migraine

Migraines are a common medical condition. From a basic science point of view, the central mechanism for migraine and headache is largely unknown. In the present study, we demonstrate that cortical excitatory transmission is significantly enhanced in the anterior cingulate cortex (ACC)-a brain region which is critical for pain perception. Biochemical studies found that the phosphorylation levels of both the NMDA receptor GluN2B and AMPA receptor GluA1 were enhanced in ACC of migraine rats. Both the presynaptic release of glutamate and postsynaptic responses of AMPA receptors and NMDA receptors were enhanced. Synaptic long-term potentiation (LTP) was occluded. Furthermore, behavioral anxiety and nociceptive responses were increased, which were reversed by application of AC1 inhibitor NB001 within ACC. Our results provide strong evidence that cortical LTPs contribute to migraine-related pain and anxiety. Drugs that inhibit cortical excitation such as NB001 may serve as potential medicines for treating migraine in the future.

Quantitative and Qualitative Pain Evaluation in Response to OnabotulinumtoxinA for Chronic Migraine: An Observational Real-Life Study

(1) Background: Randomized controlled trials and real-life studies demonstrated the efficacy of OnabotulinumtoxinA (OBT-A) for CM prevention. However, no studies specifically addressed its effect on pain's quantitative intensity and qualitative characteristics. (2) Methods: This is an ambispective study: a post-hoc retrospective analysis of real-life prospectively collected data from two Italian headache centers on CM patients treated with OBT-A over one year (i.e., Cy1-4). The primary endpoint was the changes in pain intensity (Numeric Rating Scale, NRS; the Present Pain Intensity (PPI) scale, the 6-point Behavioral Rating Scale (BRS-6)) and quality scale (the short-form McGill Pain Questionnaire (SF-MPQ)) scores. We also assessed the relationship between changes in intensity and quality of pain and disability scale (MIDAS; HIT-6) scores, monthly headache days (MHDs), and monthly acute medication intake (MAMI) (3) Results: We retrieved 152 cases (51.5 years SD 11.3, 80.3% females). From baseline to Cy-4, MHDs, MAMI, NRS, PPI, and BRS-6 scores decreased (consistently p < 0.001). Only the throbbing (p = 0.004), splitting (p = 0.018), and sickening (p = 0.017) qualities of pain collected in the SF-MPQ were reduced. Score variations in MIDAS related to those in PPI scales (p = 0.035), in the BRS-6 (p = 0.001), and in the NRS (p = 0.003). Similarly, HIT-6 score changes related to PPI score modifications (p = 0.027), in BRS-6 (p = 0.001) and NRS (p = 0.006). Conversely, MAMI variation was not associated with qualitative or quantitative pain score modifications except BRS-6 (p = 0.018). (4) Conclusions: Our study shows that OBT-A alleviates migraine by reducing its impact on multiple aspects, such as frequency, disability, and pain intensity. The beneficial effect on pain intensity seems specific to pain characteristics related to C-fiber transmission and is associated with a reduction in migraine-related disability.

Evaluating the efficacy of CGRP mAbs and gepants for the preventive treatment of migraine: A systematic review and network meta-analysis of phase 3 randomised controlled trials

BACKGROUND

Several novel treatments targeting the calcitonin gene-related peptide pathway have been developed for migraine. We evaluated the efficacy of these medications, including atogepant, rimegepant, erenumab, eptinezumab, fremanezumab, and galcanezumab, for the prevention of migraine via network meta-analysis.

METHODS

Databases, including MEDLINE via PubMed, EMBASE, and Cochrane central, were systematically reviewed, and all eligible phase 3 randomised controlled trials were included.

RESULTS

Nineteen studies (n = 14,584 participants) were included. Studies included episodic (n = 11) and chronic (n = 4) migraine or both (n = 4). All interventions, except for eptinzumab 30 mg, significantly reduced mean monthly migraine days compared to placebo. All medications had a higher ≥50% responder rate than placebo and results were statistically significant in those with the subcutaneous or intravenous route of administrations, but not with the oral one. All medications significantly reduced mean monthly headache days, although no data for this outcome was available for rimegepant, and mean monthly acute medication days, with no data for eptinezumab.

CONCLUSION

The results show that medications targeting calcitonin gene-related peptide were effective in preventing migraine compared to placebo. Considering limitations of single studies, different populations such as episodic and chronic migraine, and the absence of head-to-head trials, all novel treatments decreased mean monthly migraine and headache days, and showed higher 50%, 75% and 100% responder rates than placebo.Trial registration: PROSPERO registration: CRD42022310579.

Calcitonin gene-related peptide (CGRP) monoclonal antibodies for migraine

The introduction of calcitonin gene-related peptide monoclonal antibodies represents a step forward in preventive migraine treatment as the first agents to target the underlying pathogenesis of migraine. In trials they act more quickly, have better long-term adherence and appear to be better tolerated than other treatments. Major disadvantages are their high cost and unknown safety in pregnancy and in cardiovascular disease. To mitigate these concerns, they should be used according to guidance produced by professional bodies, with defined starting and stopping criteria. We do not yet know whether they are more effective than standard care; many patients may still be better treated by other means, in particular addressing lifestyle factors and medication-overuse headache.

Annual indirect costs savings in patients with episodic or chronic migraine: a post-hoc analysis of phase 3 galcanezumab clinical trials in the United States

BACKGROUND

Galcanezumab (GMB) improved quality-of-life and reduced disability of patients with episodic (EM) and chronic migraine (CM) in Phase 3 trials.

AIM

To estimate indirect cost savings associated with GMB treatment in patients with migraine in the United States (US).

METHODS

We analyzed data of patients from the US from three randomized, Phase 3, double-blind, placebo (PBO)-controlled GMB studies: EVOLVE-1 and EVOLVE-2 (EM patients), REGAIN (CM patients). Annual indirect costs were calculated using items of the Migraine Disability Assessment (MIDAS) questionnaire: lost time/productivity at work/school, household work, and leisure time. All costs were annualized and expressed in 2019 US dollars. While the main analysis considered lost time/productivity at work/school and household work as a full day, a sensitivity analysis was performed by discounting them by half. For EM, annual indirect costs savings were estimated using mixed model repeated measures analysis. For CM, ANCOVA models were used to estimate annual indirect costs savings as change from baseline.

RESULTS

The analysis included 805 patients with EM (mean age = 41.4 years; PBO = 534; GMB = 271) and 423 patients with CM (mean age = 38.9 years; PBO = 279; GMB = 144). Compared to PBO, GMB significantly reduced annual indirect costs among patients with EM at 3 months (least square mean [95% confidence interval] work/school = $1,883.6 [603.64-3,163.65], p = .0040, household work = $628.9 [352.95-904.88], p <.0001, and leisure activity = $499.17 [42.36-955.98], p = .0323) and 6 months (work/school = $2,382.29 [1,065.48-3,699.10], p = .0004, household work = $559.45 [268.99-849.90], p = .0002, and leisure activity = $753.81 [334.35-1,173.27], p = .0004), whereas a significant difference was not observed among patients with CM. Sensitivity analysis results were similar to primary analysis results.

CONCLUSIONS

GMB treatment versus PBO resulted in significantly greater indirect cost savings in patients with EM through improved productivity at work/school, household work, and leisure days. Patients with CM receiving GMB versus PBO attained greater cost savings, although not statistically significant, through reduced lost productivity at work/school.

Trends in utilization and costs of migraine medications, 2017–2020

Objective

This study examines changes in utilization and costs trends associated with migraine medications.

Background

Migraine attacks are a burden to many patients. There are many pharmacotherapy options available with newer migraine drug classes entering the market in the past decade. Little is known about the use, associated costs, and the impact of the newer agents.

Methods

This retrospective, cross-sectional study examined 2017–2020 administrative claims from a large national pharmacy benefits manager. Patients aged ≥ 18 years enrolled in commercial, Medicare, Medicaid, or health insurance exchange insurance plans who filled ≥ 2 prescription claims for triptans, ergotamines, isometheptenes, gepants, ditans, and CGRP mABs were included. A two-sample t-test was conducted to estimate whether differences in mean utilization and costs between 2017 and 2020 were statistically significant for migraine drug classes, except for CGRP mABs, which were estimated between 2018 and 2020.

Results

The sample ranged from 161,369 (2017) to 240,330 (2020) patients. 84.5% (n = 203,110; 2020) of patients were women. The number of 30-day adjusted prescription fills for prophylaxis remained stable over the four-year period, except for CGRP mABs, which increased from 0.5% (n = 0.007; 2018) to 5.3% (n = 0.075; 2020). Antiepileptics, antidepressants and beta blockers were the most common prophylaxes, while triptans, non-steroidal anti-inflammatory drugs/non-narcotic analgesics and opioids were the most common treatments utilized. CGRP mABs were the most expensive, while utilization of triptans were the highest. CGRP mABs had the largest increase in utilization (177.5%) and costs (166.3%) PPPM in 2020 ($291.17) compared to 2018 ($109.35), the year they were first available (p < 0.001). Between 2018 and 2020, costs increased overall and for commercial and Medicare enrollees, but remained unchanged for Medicaid and HIX members.

Conclusion

Our study demonstrates a shift in migraine medication utilization from 2017–2020, where increased use of CGRP mABs had a significant contribution to increased costs. These increased pharmacy costs must be weighed against the improved tolerability of these agents likely resulting in other healthcare and indirect cost savings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-022-01476-y.

Migraine Prevention through Ketogenic Diet: More than Body Mass Composition Changes

The ketogenic diet (KD) is gaining attention as a preventive treatment for migraine, which is sustained by many pre-clinical and clinical data. KD is also used for weight loss, and there is a relation between migraine and weight excess, but it is speculated that KD efficacy on migraine may go beyond this effect. We conducted a retrospective observational study on 23 migraine patients who received a KD and were evaluated at the baseline and then after 3 months both from a neurological and a nutritional point of view, including body mass composition analysis. We observed a reduction in monthly headache days (12.5 ± 9.5 vs. 6.7 ± 8.6; p < 0.001) and in days of acute medication intake (11.06 ± 9.37 vs. 4.93 ± 7.99; p = 0.008). We also observed a reduction in patients’ weight (73.8 ± 15.2 vs. 68.4 ± 14.6; p < 0.001) and BMI (26.9 ± 6.2 vs. 23.7 ± 8.1; p < 0.001) with a decrement of the fat mass (28.6 ± 12.5 vs. 20.6 ± 9.8; p < 0.001). Patients who responded to KD and those who did not had no differences with respect to weight or fat mass loss. These data corroborate the utilization of KD as a preventive treatment for migraine and suggest that the efficacy of such an intervention is not only due to weight or fat mass loss but probably relies on other mechanisms specific to KD.

The Anti-CGRP Antibody Fremanezumab Lowers CGRP Release from Rat Dura Mater and Meningeal Blood Flow

Monoclonal antibodies directed against the neuropeptide calcitonin gene-related peptide (CGRP) belong to a new generation of therapeutics that are effective in the prevention of migraine. CGRP, a potent vasodilator, is strongly implicated in the pathophysiology of migraine, but its role remains to be fully elucidated. The hemisected rat head preparation and laser Doppler flowmetry were used to examine the effects on CGRP release from the dura mater and meningeal blood flow of the subcutaneously injected anti-CGRP monoclonal antibody fremanezumab at 30 mg/kg, when compared to an isotype control antibody. Some rats were administered glycerol trinitrate (GTN) intraperitoneally to produce a migraine-like sensitized state. When compared to the control antibody, the fremanezumab injection was followed by reduced basal and capsaicin-evoked CGRP release from day 3 up to 30 days. The difference was enhanced after 4 h of GTN application. The samples from the female rats showed a higher CGRP release compared to that of the males. The increases in meningeal blood flow induced by acrolein (100 µM) and capsaicin (100 nM) were reduced 13–20 days after the fremanezumab injection, and the direct vasoconstrictor effect of high capsaicin (10 µM) was intensified. In conclusion, fremanezumab lowers the CGRP release and lasts up to four weeks, thereby lowering the CGRP-dependent meningeal blood flow. The antibody may not only prevent the released CGRP from binding but may also influence the CGRP release stimulated by noxious agents relevant for the generation of migraine pain.

Post-traumatic headache: Pathophysiology and management - A review

Background

Post-traumatic headache (PTH) is a common secondary headache due to traumatic brain injury. In the past, significant research has been conducted to understand the pathophysiology and treatment options for PTH. However, PTH still lacks evidence-based treatment, and most of the management depends on the primary phenotype observed in the patient.

Objective

The main objective of this review is to provide a single reference that covers the current understanding of the pathophysiology and the treatment options available for PTH.

Methods

A detailed literature search on PubMed was performed, and a narrative review was prepared.

Results

The pathophysiology of PTH is multifactorial. Acute PTH may be attributed to increased peripheral pain sensitization with impaired pain inhibiting pathways. Chronic or persistent PTH may be due to a chronic inflammatory response and peripheral as well as central sensitization. The mechanism responsible for the transition of acute to persistent PTH is unknown. The migraine-like phenotype is reported to be the most prevalent headache type seen in PTH. New targets for preventive treatment have been identified in recent years, such as neuropeptides like calcitonin-gene-related peptide (CGRP), nitric oxide, and glutamate. The preventive pharmacological and non-pharmacological strategies employed for migraine (e.g. anti-CGRP monoclonal antibodies, onabotulinumtoxinA, physical therapy, cognitive and behavioral treatment, and neurostimulation techniques) have shown in preliminary studies that they are potentially efficacious, but large, randomized, double blind, placebo controlled trials are needed to further establish these as treatment options for PTH.

Conclusions

The lack of evidence-based treatment for PTH has created a need for future large trials to confirm the safety and efficacy of the currently employed treatments.

The endocannabinoid system and related lipids as potential targets for the treatment of migraine-related pain

BACKGROUND

Migraine is a complex and highly disabling neurological disease whose treatment remains challenging in many patients, even after the recent advent of the first specific-preventive drugs, namely monoclonal antibodies that target calcitonin gene-related peptide. For this reason, headache researchers are actively searching for new therapeutic targets. Cannabis has been proposed for migraine treatment, but controlled clinical studies are lacking. A major advance in cannabinoid research has been the discovery of the endocannabinoid system (ECS), which consists of receptors CB1 and CB2; their endogenous ligands, such as N-arachidonoylethanolamine; and the enzymes that catalyze endocannabinoid biosynthesis or degradation. Preclinical and clinical findings suggest a possible role for endocannabinoids and related lipids, such as palmitoylethanolamide (PEA), in migraine-related pain treatment. In animal models of migraine-related pain, endocannabinoid tone modulation via inhibition of endocannabinoid-catabolizing enzymes has been a particular focus of research.

METHODS

To conduct a narrative review of available data on the possible effects of cannabis, endocannabinoids, and other lipids in migraine-related pain, relevant key words were used to search the PubMed/MEDLINE database for basic and clinical studies.

RESULTS

Endocannabinoids and PEA seem to reduce trigeminal nociception by interacting with many pathways associated with migraine, suggesting a potential synergistic or similar effect.

CONCLUSIONS

Modulation of the metabolic pathways of the ECS may be a basis for new migraine treatments. The multiplicity of options and the wealth of data already obtained in animal models underscore the importance of further advancing research in this area. Multiple molecules related to the ECS or to allosteric modulation of CB1 receptors have emerged as potential therapeutic targets in migraine-related pain. The complexity of the ECS calls for accurate biochemical and pharmacological characterization of any new compounds undergoing testing and development.

Deterioration of headache impact and health-related quality of life in migraine patients after cessation of preventive treatment with CGRP(-receptor) antibodies

Background

Migraine preventive treatment with CGRP(−receptor) monoclonal antibodies (mAbs) has a positive effect on patients’ health-related quality of life (HRQoL). The German treatment guidelines recommend discontinuing successful treatment with CGRP(−receptor) mAbs after 6–12 months. We aimed to evaluate headache-specific and generic HRQoL for three months after discontinuation of CGRP(−receptor) mAb treatment.

Methods

We conducted a prospective, longitudinal cohort study, including patients with migraine after 8–12 months of therapy with a CGRP(−R) mAb and before a planned discontinuation attempt. HRQoL was assessed at the time of the last mAbs injection (V1), eight weeks later (V2), and sixteen weeks later (V3). For headache-specific HRQoL, we used the Headache Impact Test-6 (HIT-6). Generic HRQoL was determined with the EuroQol-5-Dimension-5-Level (ED-5D-5L) form, and the Short-Form 12 (SF-12), which comprises a Physical Component Summary (PCS-12) and a Mental Component Summary (MCS-12).

Questionnaires’ total scores were compared across the three observation points using nonparametric procedures.

Results

The study cohort consisted of n = 61 patients (n = 29 treated with the CGRP-receptor mAb erenumab and n = 32 with the CGRP mAbs galcanezumab or fremanezumab). The HIT-6 sum score was 59.69 ± 6.90 at V1 and increased by 3.69 ± 6.21 at V3 (p < 0.001), indicating a greater headache impact on patients’ lives. The mean total EQ-D5-L5 score declined from 0.85 ± 0.17 at V1 by − 0.07 ± 0.18 at V3 (p = 0.013). Both Mental and Physical Component Scores of the SF-12 worsened significantly during treatment discontinuation: The PCS-12 total score decreased by − 4.04 ± 7.90 from V1 to V3 (p = 0.013) and the MCS-12 score by − 2.73 ± 9.04 (p = 0.003). Changes in all questionnaires’ scores but the MCS-12 were already significant in the first month of the drug holiday (V2).

Conclusions

Our results show a significant decline in headache impact and generic HRQoL of migraine patients after treatment discontinuation of a CGRP(−R) mAb. The observed deterioration is above the established minimally clinically important differences for each of the questionnaires and can therefore be considered clinically meaningful. Monitoring HRQoL during a discontinuation attempt could facilitate the decision whether or not to resume preventive treatment with CGRP(−R) mAbs.

Erenumab for Migraine Prevention in a 1-Year Compassionate Use Program: Efficacy, Tolerability, and Differences Between Clinical Phenotypes

During a 1-year compassionate use program, 156 patients with migraine self-administered a monthly dose of erenumab 140 mg with a subcutaneous autoinjector. Main inclusion criteria were: ≥ 4 migraine days/month and ≥two prior prophylactic treatment failures. The patients covered the migraine severity spectrum from episodic migraine (EM) (n = 80) to chronic migraine (CM) (n = 76). During the 3rd month of treatment, monthly headache days decreased by 45.7% in EM and 35.5% in CM. The 50% responder rate for reduction in monthly headache days was significantly higher in EM (55%) than in CM (43%) (p = 0.05). In both the migraine subgroups, the clinical improvement vs. baseline was already significant during the 1st month of treatment (p < 0.001). There were also significant reductions in mean headache severity, duration, and monthly days with acute drug intake. The 30% responder rate at 3 months was 60% in CM and 54.1% of patients reversed from CM to EM. The therapeutic effect was maintained at 12 months when 50% responder rates, considering discontinuation for lack of efficacy or adverse effects as 0% response, still were 51% in EM and 41% in CM. A total of 10 patients with EM (12.5%) and 23 patients with CM (30.3%) had discontinued treatment, considering the treatment as ineffective. At 3 months, 48% of patients reported non-serious adverse events among which the most frequent was constipation (20.5%); corresponding figures at 12 months were 30 and 15%. Discontinuation due to an adverse effect for the entire 12 month period was rare (3.8%). The lower efficacy in CM than in EM was mainly due to a very low 50% responder rate in patients with CM with continuous pain (13%) as compared to CM with pain-free periods (58%) (p < 0.001). Similarly, the 50% responder rate was lower in patients with ≥two prior prophylactic treatment failures (40.5%) compared to those with two failures (70%) (p < 0.05). There was no significant efficacy difference between low (4-7 migraine days/month, n = 22) and high frequency (8-14 days, n = 59) EM nor between patients with CM with (n = 50) or without (n = 26) acute medication overuse. Erenumab had no effect on the frequency of auras. Taken together, erenumab 140 mg monthly was highly effective for migraine prophylaxis over the whole severity spectrum of the disease, except in patients with continuous headaches. Its effect is significant after the first injection, quasi-maximal after the second injection, and does not wear off after 12 months. The most frequent adverse effect was constipation. These results are compared to those published for erenumab in the pivotal randomized placebo-controlled trials and to those reported in several recent real-world studies.

Preventive treatment with CGRP monoclonal antibodies restores brain stem habituation deficits and excitability to painful stimuli in migraine: results from a prospective case-control study

Background & Objectives

Calcitonin gene-related peptide ligand/receptor (CGRP) antibodies effectively reduce headache frequency in migraine. It is understood that they act peripherally, which raises the question whether treatment merely interferes with the last stage of headache generation or, alternatively, causes secondary adaptations in the central nervous system and might thus possess disease modifying potential. This study addresses this question by investigating the nociceptive blink reflex (nBR), which is closely tied to central disease activity, before and after treatment with CGRP antibodies.

Methods

We enrolled 22 patients suffering episodic migraine (21 female, 46.2 ± 13.8 years of age) and 22 age-/gender-matched controls. Patients received assessments of the nBR (R2 component, 10 trials, 6 stimuli/trial) before (V0) and three months (V3) after treatment with CGRP antibodies started, controls were assessed once. The R2 area (R2a) and habituation (R2h; gradient of R2a against stimulus order) of the stimulated/non-stimulated side (_s/_ns) following repeated supraorbital stimulation provide a direct readout of brainstem excitability and habituation as key mechanisms in migraine.

Results

All patients showed a substantial reduction of headache days/month (V0: 12.4±3.3, V3: 6.6 ± 4.9). R2a_s (F_global=5.86, p<0.001; block 1: R2a_s: -28%, p<0.001) and R2a_ns (F_global=8.22, p<0.001, block 1: R2a_ns: -22%, p=0.003) were significantly decreased, and R2h_ns was significantly enhanced (F_global=3.07, p<0.001; block 6: R2h_ns: r=-1.36, p=0.007) from V0 to V3. The global test for changes of R2h_s was non-significant (F_global=1.46, p=0.095). Changes of R2h significantly correlated with improvement of headache frequency (R2h_s, r=0.56, p=0.010; R2h_ns: r=0.45, p=0.045). None of the nBR parameters assessed at baseline predicted treatment response.

Discussion

We provide evidence that three months of treatment with CGRP antibodies restores brain stem responses to painful stimuli and thus might be considered disease modifying. The nociceptive blink reflex may provide a biomarker to monitor central disease activity. Future studies should evaluate the blink reflex as a clinical biomarker to predict treatment response at baseline and to establish the risk of relapse after treatment discontinuation.

Trial registration

This trial was prospectively registered at clinicaltrials.gov (ID: NCT04019496, date of registration: July 15, 2019).

Headache and immunological/autoimmune disorders: a comprehensive review of available epidemiological evidence with insights on potential underlying mechanisms

Several lines of evidence support a role of the immune system in headache pathogenesis, with particular regard to migraine. Firstly, alterations in cytokine profile and in lymphocyte subsets have been reported in headache patients. Secondly, several genetic and environmental pathogenic factors seem to be frequently shared by headache and immunological/autoimmune diseases. Accordingly, immunological alterations in primary headaches, in particular in migraine, have been suggested to predispose some patients to the development of immunological and autoimmune diseases. On the other hand, pathogenic mechanisms underlying autoimmune disorders, in some cases, seem to favour the onset of headache. Therefore, an association between headache and immunological/autoimmune disorders has been thoroughly investigated in the last years. The knowledge of this possible association may have relevant implications in the clinical practice when deciding diagnostic and therapeutic approaches. The present review summarizes findings to date regarding the plausible relationship between headache and immunological/autoimmune disorders, starting from a description of immunological alteration of primary headaches, and moving onward to the evidence supporting a potential link between headache and each specific autoimmune/immunological disease.

CGRP monoclonal antibodies in migraine: an efficacy and tolerability comparison with standard prophylactic drugs

BACKGROUND

Several drugs are available for the preventive treatment of both episodic and chronic migraine. The choice of which therapy to initiate first, second, or third is not straightforward and is based on multiple factors, including general efficacy, tolerability, potential for serious adverse events, comorbid conditions, and costs. Recently, a new class of migraine preventive drugs was introduced, i.e. monoclonal antibodies against calcitonin gene-related peptide (CGRP) or its receptor.

METHODS

The present article summarizes the evidence gathered with this new migraine preventive drug class from randomized placebo-controlled clinical trials. It further puts this into perspective next to the evidence gained by the most widely used agents for the prevention of episodic and chronic migraine with an emphasis on efficacy and the robustness with which this efficacy signal was obtained.

RESULTS

Although being a relatively new class of migraine preventive drugs, monoclonal antibodies blocking the CGRP pathway have an efficacy which is at least comparable if not higher than those of the currently used preventive drugs. Moreover, the robustness of this efficacy signal is substantiated by several randomized clinical trials each including large numbers of patients. In addition, because of their excellent tolerability and with long-term safety data emerging, they seem to have an unprecedented efficacy over adverse effect profile, clearly resulting in an added value for migraine prevention.

CONCLUSIONS

Balancing the data presented in the current manuscript with additional data concerning long term safety on the one hand and cost issues on the other hand, can be of particular use to health policy makers to implement this new drug class in the prevention of migraine.

Migraine evolution after the cessation of CGRP(-receptor) antibody prophylaxis: a prospective, longitudinal cohort study

BACKGROUND

National and international guidelines recommend stopping migraine prophylaxis with CGRP(-receptor) monoclonal antibodies after 6-12 months of successful therapy. In this study, we aimed to analyze the course of migraine for four months after the cessation of CGRP(-receptor) antibodies use.

METHODS

This longitudinal cohort study included patients with migraine who received a CGRP-(receptor) antibody for ≥8 months before treatment cessation. We analyzed headache data in the four-week period prior to mAb treatment initiation (baseline), in the month before the last mAb injection, in weeks 5-8 and 13-16 after last treatment. Primary endpoint of the study was the change of monthly migraine days from the month before last treatment to weeks 13-16. Secondary endpoints were changes in monthly headache days and monthly days with acute medication use.

RESULTS

A total of 62 patients equally distributed between prophylaxis with the CGRP-receptor antibody erenumab and the CGRP antibodies galcanezumab or fremanezumab participated in the study. Patients reported 8.2 ± 6.6 monthly migraine days in the month before last treatment. Monthly migraine days gradually increased to 10.3 ± 6.8 in weeks 5-8 (p = 0.001) and to 12.5 ± 6.6 in weeks 13-16 (p < 0.001) after drug cessation. Monthly migraine days in weeks 13-16 were not different from baseline values (-0.8 ± 5.4; p > 0.999). Monthly headache days and monthly days with acute medication use showed a similar pattern.

CONCLUSIONS

The cessation of CGRP(-receptor) antibodies migraine prophylaxis was associated with a significant increase of migraine frequency and acute medication intake over time.

CGRP-dependent signalling pathways involved in mouse models of GTN- cilostazol- and levcromakalim-induced migraine

BACKGROUND

Knowledge of exact signalling events during migraine attacks is lacking. Various substances are known to trigger migraine attacks in patients and calcitonin gene-related peptide antagonising drugs are effective against migraine pain. Here, we investigated the signalling pathways involved in three different mouse models of provoked migraine and relate them to calcitonin gene-related peptide and other migraine-relevant targets.

METHODS

In vivo mouse models of glyceryl trinitrate-, cilostazol- and levcromakalim-induced migraine were applied utilising tactile sensitivity to von Frey filaments as measuring readout. Signalling pathways involved in the three models were dissected by use of specific knockout mice and chemical inhibitors. In vivo results were supported by ex vivo wire myograph experiments measuring arterial dilatory responses and ex vivo calcitonin gene-related peptide release from trigeminal ganglion and trigeminal nucleus caudalis from mice.

RESULTS

Glyceryl trinitrate-induced hypersensitivity was dependent on both prostaglandins and transient receptor potential cation channel, subfamily A, member 1, whereas cilostazol- and levcromakalim-induced hypersensitivity were independent of both. All three migraine triggers activated calcitonin gene-related peptide signalling, as both receptor antagonism and antibody neutralisation of calcitonin gene-related peptide were effective inhibitors of hypersensitivity in all three models. Stimulation of trigeminal ganglia and brain stem tissue samples with cilostazol and levcromakalim did not result in release of calcitonin gene-related peptide, and vasodilation following levcromakalim stimulation was independent of CGRP receptor antagonism.

CONCLUSION

The mouse models of glyceryl trinitrate-, cilostazol- and levcromakalim- induced migraine all involve calcitonin gene-related peptide signalling in a complex interplay between different cell/tissue types. These models are useful in the study of migraine mechanisms.

Benefit-Risk Assessment of Galcanezumab Versus Placebo for the Treatment of Episodic and Chronic Migraine Using the Metrics of Number Needed to Treat and Number Needed to Harm

INTRODUCTION

Subcutaneous galcanezumab was an effective, well-tolerated preventive treatment for adults with episodic (EM) or chronic migraine (CM) in 4 phase 3 randomized controlled trials: EVOLVE-1, EVOLVE-2, REGAIN, and CONQUER. Number needed to treat (NNT) and to harm (NNH) are metrics of effect size used to evaluate benefit-risk profiles. This study evaluated NNT, NNH, and benefit-risk profiles (measured as likelihood to be helped or harmed, LHH) of galcanezumab 120 mg versus placebo in patients with EM or CM.

METHODS

Primary efficacy outcomes were responses defined as ≥ 30%, ≥ 50%, and ≥ 75% reductions from baseline in number of monthly migraine headache days in patients with EM (EVOLVE-1; EVOLVE-2; CONQUER) and CM (REGAIN; CONQUER); corresponding NNTs to achieve respective responses; and corresponding NNHs for discontinuations due to adverse events (DCAEs) among the safety population. Secondary efficacy outcomes were responses for patients with ≥ 2 failed prior preventive treatments due to lack of efficacy and/or for tolerability reasons. All LHHs were based on ≥ 50% response and DCAEs.

RESULTS

During double-blind treatment periods with galcanezumab 120 mg, NNT to achieve ≥ 30% and ≥ 50% responses ranged from 4 to 10 and NNT to achieve ≥ 75% responses ranged from 5 to 23 in individual trials. NNH ranged from 93 to 1000, while LHH ranged from 18.6 to 104.6. NNTs were generally more robust among patients with EM than with CM; however, in patients with failure of ≥ 2 prior preventive treatments, NNTs to achieve ≥ 30% and ≥ 50% responses were similar between patients with CM and EM. NNHs were imputed as 1000 for both migraine types. Resulting LHHs were 178.8 (EM) and 127 (CM).

CONCLUSION

Across 4 trials, galcanezumab 120 mg demonstrated a favorable benefit-risk profile versus placebo, based on low NNTs to achieve response and high NNHs associated with DCAEs. LHH values consistently far exceeded 1.

TRIAL REGISTRATION NUMBERS

EVOLVE-1: ClinicalTrials.gov identifier, NCT02614183; EVOLVE-2: ClinicalTrials.gov identifier, NCT02614196; REGAIN: ClinicalTrials.gov identifier, NCT02614261; CONQUER: ClinicalTrials.gov identifier, NCT03559257.

Revised guidelines of the French headache society for the diagnosis and management of migraine in adults. Part 2: Pharmacological treatment

The French Headache Society proposes updated French guidelines for the management of migraine. This article presents the second part of the guidelines, which is focused on the pharmacological treatment of migraine, including both the acute treatment of attacks and the prophylaxis of episodic migraine as well as chronic migraine with and without medication overuse. The specific situations that can be encountered in women with migraine are also discussed, including pregnancy, menstrual migraine, contraception and hormonal replacement therapy.

CGRP-antibodies, topiramate and botulinum toxin type A in episodic and chronic migraine: A systematic review and meta-analysis

Background

The approval of monoclonal antibodies for prevention of migraine has revolutionized treatment for patients. Oral preventatives are still considered first line treatments as head-to-head trials comparing them with antibodies are lacking.

Methods

The main purpose of this study was to provide a comparative overview of the efficacy of three commonly prescribed migraine preventative medication classes. For this systematic review and meta-analysis, we searched the databases CENTRAL, EMBASE, and MEDLINE until 20 March 2020. We included RCTs reporting the 50% response rates for topiramate, Botulinum Toxin Type A and monoclonal antibodies against CGRP(r). Studies were excluded if response rates were not reported, treatment allocation was unclear, or if study quality was insufficient. Primary outcome measure were the 50% response rates. The pooled odds ratios with 95% confidence intervals were calculated with the random effects model. The study was registered at PROSPERO (CRD42020222880).

Findings

We identified 6552 reports. Thirty-two were eligible for our review. Studies assessing monoclonal antibodies included 13,302 patients and yielded pooled odds ratios for the 50% response rate of 2.30 (CI: 2.11–2.50). Topiramate had an overall effect estimate of 2.70 (CI: 1.97–3.69) with 1989 included patients and Botulinum Toxin Type A achieved 1.28 (CI: 0.98–1. 67) with 2472 patients included.

Interpretation

Topiramate, botulinum toxin type A and monoclonal antibodies showed higher odds ratios in achieving a 50% response rate compared to placebo. Topiramate numerically demonstrated the greatest effect size but also the highest drop-out rate.

Excitatory Effects of Calcitonin Gene-Related Peptide (CGRP) on Superficial Sp5C Neurons in Mouse Medullary Slices

The neuromodulator calcitonin gene-related peptide (CGRP) is known to facilitate nociceptive transmission in the superficial laminae of the spinal trigeminal nucleus caudalis (Sp5C). The central effects of CGRP in the Sp5C are very likely to contribute to the activation of central nociceptive pathways leading to attacks of severe headaches like migraine. To examine the potential impacts of CGRP on laminae I/II neurons at cellular and synaptic levels, we performed whole-cell patch-clamp recordings in juvenile mouse brainstem slices. First, we tested the effect of CGRP on cell excitability, focusing on neurons with tonically firing action potentials upon depolarizing current injection. CGRP (100 nM) enhanced tonic discharges together with membrane depolarization, an excitatory effect that was significantly reduced when the fast synaptic transmissions were pharmacologically blocked. However, CGRP at 500 nM was capable of exciting the functionally isolated cells, in a nifedipine-sensitive manner, indicating its direct effect on membrane intrinsic properties. In voltage-clamped cells, 100 nM CGRP effectively increased the frequency of excitatory synaptic inputs, suggesting its preferential presynaptic effect. Both CGRP-induced changes in cell excitability and synaptic drives were prevented by the CGRP receptor inhibitor BIBN 4096BS. Our data provide evidence that CGRP increases neuronal activity in Sp5C superficial laminae by dose-dependently promoting excitatory synaptic drive and directly enhancing cell intrinsic properties. We propose that the combination of such pre- and postsynaptic actions of CGRP might underlie its facilitation in nociceptive transmission in situations like migraine with elevated CGRP levels.

Update on noninvasive neuromodulation for migraine treatment-Vagus nerve stimulation

Noninvasive neurostimulation methods are particularly suited for migraine treatment thanks to their most favorable adverse event profile. Among them, noninvasive vagus nerve stimulation (nVNS) has raised great hope because of the role the vagus nerve is known to play in pain modulation, inflammation and brain excitability. We will critically review the clinical studies performed for migraine attack treatment and migraine prevention with the GammaCore® device, which allows cervical vagus nerve stimulation. nVNS is effective for the abortive treatment of migraine attacks, although the effect size is modest and numbers-to-treat appear not superior to those of other noninvasive neurostimulation methods, and inferior to those of oral triptans. The effect of nVNS with the GammaCore® in migraine prevention is not superior to sham stimulation, except possibly in patients with high adherence to the treatment. Both in acute and preventive trials, nVNS was characterized by an outstanding tolerance and safety profile, like the other noninvasive neurostimulation techniques. In physiological animal and human studies, cervical nVNS was shown to generate somatosensory evoked responses, to modulate pain perception and several areas of the cerebral pain network, and to inhibit experimental cortical spreading depression, which are relevant effects for migraine therapy.