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Background Acute and persistent post-traumatic headache are often debilitating consequences of traumatic brain injury. Underlying physiological mechanisms of post-traumatic headache and its persistence remain unknown, and there are currently no approved therapies for these conditions. Post-traumatic headache often presents with a migraine-like phenotype. As calcitonin-gene related peptide promotes migraine headache, we explored the efficacy and timing of intervention with an anti- calcitonin-gene related peptide monoclonal antibody in novel preclinical models of acute post-traumatic headache and persistent post-traumatic headache following a mild traumatic brain injury event in mice. Methods Male, C57Bl/6 J mice received a sham procedure or mild traumatic brain injury resulting from a weight drop that allowed free head rotation while under minimal anesthesia. Periorbital and hindpaw tactile stimulation were used to assess mild traumatic brain injury-induced cutaneous allodynia. Two weeks after the injury, mice were challenged with stress, a common aggravator of migraine and post-traumatic headache, by exposure to bright lights (i.e. bright light stress) and cutaneous allodynia was measured hourly for 5 hours. A murine anti- calcitonin-gene related peptide monoclonal antibody was administered after mild traumatic brain injury at different time points to allow evaluation of the consequences of either early and sustained calcitonin-gene related peptide sequestration or late administration only prior to bright light stress. Results Mice with mild traumatic brain injury, but not a sham procedure, exhibited both periorbital and hindpaw cutaneous allodynia that resolved by post-injury day 13. Following resolution of injury-induced cutaneous allodynia, exposure to bright light stress re-instated periorbital and hindpaw cutaneous allodynia in injured, but not sham mice. Repeated administration of anti-calcitonin-gene related peptide monoclonal antibody at 2 hours, 7 and 14 days post mild traumatic brain injury significantly attenuated the expression of cutaneous allodynia when evaluated over the 14-day post injury time course and also prevented bright light stress-induced cutaneous allodynia in injured mice. Administration of anti-calcitonin-gene related peptide monoclonal antibody only at 2 hours and 7 days after mild traumatic brain injury blocked injury-induced cutaneous allodynia and partially prevented bright light stress-induced cutaneous allodynia. A single administration of anti-calcitonin-gene related peptide monoclonal antibody after the resolution of the peak injury-induced cutaneous allodynia, but prior to bright light stress challenge, did not prevent bright light stress-induced cutaneous allodynia. Conclusions We used a clinically relevant mild traumatic brain injury event in mice along with a provocative stimulus as novel models of acute post-traumatic headache and persistent post-traumatic headache. Following mild traumatic brain injury, mice demonstrated transient periorbital and hindpaw cutaneous allodynia suggestive of post-traumatic headache-related pain and establishment of central sensitization. Following resolution of injury-induced cutaneous allodynia, exposure to bright light stress re-established cutaneous allodynia, suggestive of persistent post-traumatic headache-related pain. Continuous early sequestration of calcitonin-gene related peptide prevented both acute post-traumatic headache and persistent post-traumatic headache. In contrast, delayed anti-calcitonin-gene related peptide monoclonal antibody treatment following establishment of central sensitization was ineffective in preventing persistent post-traumatic headache. These observations suggest that mechanisms involving calcitonin-gene related peptide underlie the expression of acute post-traumatic headache, and drive the development of central sensitization, increasing vulnerability to headache triggers and promoting persistent post-traumatic headache. Early and continuous calcitonin-gene related peptide blockade following mild traumatic brain injury may represent a viable treatment option for post-traumatic headache and for the prevention of post-traumatic headache persistence. Abbreviations CA Cutaneous allodynia CGRP Calcitonin gene-related peptide mTBI Mild traumatic brain injury PTH Post-traumatic headache APTH Acute post-traumatic headache PPTH Persistent post-traumatic headache

Introduction ICHD-3 criteria for chronic migraine (CM) include a mixture of migraine and tension-type-like headaches and do not account for patients who have a high frequency of migraine but no other headaches. Materials and methods Patients from the Danish Headache Center and their relatives with ICHD-3 defined CM were compared with patients with high frequency episodic migraine (HFEM). Danish registries were used to compare the socioeconomic impact in these two groups. A Russian student population was used to determine the generalizability of the number of patients fulfilling CM and the proposed diagnostic criteria for CM. Results There was no difference in the demographic profile between the two groups in the Danish cohort. The number of lifelong or annual attacks ( p > 0.3), comorbid diseases, or self-reported effect of triptans ( p = 1) did not differ. HFEM patients purchased more triptans than CM patients ( p = 0.01). CM patients received more early pension ( p = 0.00135) but did not differ from HFEM patients with regard to sickness benefit ( p = 0.207), cash assistance ( p = 0.139), or rehabilitation benefit ( p = 1). Discussion Patients with HFEM are comparable to CM patients with regard to chronicity and disability. We therefore suggest classifying CM as ≥ 8 migraine days per month (proposed CM), disregarding the need for ≥ 15 headache days per month. The proposed diagnostic criteria for CM approximately doubled the number of patients with CM in both the Danish and the Russian materials. Extending the definition of CM to include patients with HFEM will ensure that patients with significant disease burden and unmet treatment needs are identified and provided appropriate access to the range of treatment options and resources available to those with CM. Conclusion Patients with migraine on eight or more days but not 15 days with headache a month are as disabled as patients with ICHD-3 defined CM. They should be included in revised diagnostic criteria for chronic migraine.

Objectives To characterize unmet treatment needs in a sample of Migraine in America Symptoms and Treatment (MAST) Study participants using oral, acute prescription migraine medications. Background The MAST Study is a 2017 study of US adults with migraine that profiles current treatment patterns and identifies and quantifies unmet treatment needs. Methods Cross‐sectional data from an online survey of US adults meeting ICHD‐3 beta criteria for migraine. For inclusion in this paper, respondents self‐reported a history of 3 or more monthly headache days (MHDs) in the past 3 months and at least 1 MHD in the past 30 days, and current use of orally administered acute prescription medication for headache. Three domains of unmet need were identified: inadequate treatment response (ie, inadequate 2‐hour pain freedom, recurrence within 24 hours of initial relief), demanding attack characteristics (rapid onset of attack, headache associated with sleep), and unique patient characteristics (opioid or barbiturate overuse, cardiovascular comorbidity). Sociodemographics, oral medication use, and coexisting conditions and symptoms (ie, level of treatment optimization, psychological symptoms, attack‐related cutaneous allodynia, and migraine symptom severity) were assessed for each domain and by the number of unmet need domains. Results Overall, 15,133 respondents met inclusion criteria, 26.0% (3930/15,133) reported current use of oral acute prescription medication to treat headache. Eligible participants had a mean age of 45.0 years, 73.6% [2892/3930] were women and 81.1% [3186/3930]) were White. A total of 95.8% (3765/3930) of respondents had at least 1 unmet acute treatment need; 89.5% (3516/3930) reported demanding attack characteristics, 74.1% (2912/3930) reported inadequate treatment response, and 16.1% (634/3930) presented with unique patient characteristics. Common areas of unmet need were rapid headache onset (65.3% [2567/3930]), moderate to severe disability (55.6% [2187/3930]), inadequate 2‐hours pain freedom (49.0% [1892/3930]), and headache recurrence within 24 hours (38.0% [1493/3930]). An increasing number of unmet treatment need domains was associated with worsening psychological symptoms, attack‐related cutaneous allodynia and migraine symptom severity. Conclusion Nearly all MAST Study respondents using acute oral prescription medications for migraine reported at least 1 unmet treatment need. As unmet needs increased, so did coexisting conditions and symptom severity.

Background The sphenopalatine ganglion (SPG) has previously been targeted in trigeminal neuralgia (TN), but its role in this condition has not been established. Objective To investigate the safety of injecting onabotulinumtoxinA (BTA) toward the SPG using the MultiGuide ® in 10 patients with refractory classical TN, and collect preliminary efficacy data. Methods Twenty‐five international units (IU) of BTA were injected toward the SPG in a prospective, open‐label study in 10 patients with refractory classical TN. All patients were recruited and treated on an out‐patient basis at St. Olav's University Hospital in Trondheim (Norway). Primary outcome: adverse events (AEs). Primary efficacy outcome: number of TN attacks at weeks 5‐8 after injection compared to baseline. A treatment responder was predefined as at least 50% reduction in the median number of attacks per day between baseline and weeks 5‐8. Other efficacy outcomes were intensity of attacks (numeric rating scale, 0 to 10) and functional level (1 to 4; 1 best and 4 worst) at weeks 5‐8 after injection compared to baseline. Percentage of the day with concomitant persistent pain was registered at baseline and at weeks 1‐4, 6, 8, and 12 after injection. Patient global impression of change (PGIC) was ascertained at month 3. Results For the primary endpoint, we analyzed data for all 10 patients. For efficacy outcomes we analyzed data for 9 patients (1 patient violated protocol). We registered 13 AEs, none of which were serious. The median number of TN attacks during the 4‐week baseline and weeks 5‐8 after injection was 5.5 (range: 1.0‐51.5) and 5 (range: 0‐225.0), respectively ( P = .401). Four patients were treatment responders. The median intensity of attacks at baseline and weeks 5‐8 after injection was 6 (range: 3.0‐8.5) and 3 (range: 0.0‐9.0) respectively ( P = .024). The median functional level at baseline was 2 (range: 1.0‐3.3) and at month 2, 1 (range 1.0‐4.0; P = .750). Median percentage of the day with concomitant persistent pain was 75% (minimum 37.5%, maximum 100%) at baseline and 18.75% (minimum 0%, maximum 100%) at week 8 ( P = .023). Conclusions Injection of BTA toward the SPG using the MultiGuide ® in patients with TN appears to be safe and well tolerated. This study was negative for the main efficacy endpoint (reduction in the number of attacks from baseline to weeks 5‐8). Further studies examining the role of the SPG in TN are necessary.

Aim Evaluation of cannabinoid receptor agonists in a preclinical model of medication overuse headache. Methods Female Sprague Dawley rats received graded intraperitoneal doses of WIN55,212-2 or Δ-9-tetrahydrocannabinol (Δ-9-THC). Antinociception (tail-flick test), catalepsy and hypomotility (open field test) and impairment of motor function (rotarod test) were assessed to establish effective dosing. Rats were then treated twice daily with equianalgesic doses of WIN55,212-2 or Δ-9-THC, or vehicle, for 7 days and cutaneous tactile sensory thresholds were evaluated during and three weeks following drug discontinuation. Rats then received a one-hour period of bright light stress (BLS) on two consecutive days and tactile sensory thresholds were re-assessed. Results WIN55,212-2 and Δ-9-THC produced antinociception as well as hypomotility, catalepsy and motor impairment. Repeated administration of WIN55,212-2 and Δ-9-THC induced generalized periorbital and hindpaw allodynia that resolved within 3 weeks after discontinuation of drug. Two episodes of BLS produced delayed and long-lasting periorbital and hindpaw allodynia selectively in rats previously treated with WIN55,212-2, and Δ-9-THC. Interpretation Cannabinoid receptor agonists including Δ-9-THC produce a state of latent sensitization characterized by increased sensitivity to stress, a presumed migraine trigger. Overuse of cannabinoids including cannabis may increase the risk of medication overuse headache in vulnerable individuals.

Background Calcitonin gene-related peptide plays an important role in migraine pathophysiology. We evaluated eptinezumab, an intravenous (IV) anti-calcitonin gene-related peptide monoclonal antibody, for the prevention of chronic migraine. Objective To determine the safety, tolerability, and effectiveness of four dose levels of eptinezumab and to inform the phase 3 development program. Methods This was a phase 2b, parallel-group, double-blind, randomized, placebo-controlled, dose-ranging clinical trial. Men and women (N = 616) aged 18–55 years were included if they had a diagnosis of chronic migraine, with onset at age ≤35 years and history of chronic migraine ≥1 year. During the 28-day screening period, patients must have had ≥15 headache days, including ≥8 migraine days, with ≥5 migraine attacks as recorded in the electronic diary. Patients were assigned in a 1:1:1:1:1 ratio to eptinezumab 300, 100, 30, 10 mg or placebo, administered as a single IV infusion. The primary endpoint was the percentage of patients with a ≥75% decrease in monthly migraine days over weeks 1–12 compared with the 28-day screening period. Results The ≥75% migraine responder rates over weeks 1–12 for eptinezumab 300, 100, 30, and 10 mg were 33.3%, 31.4%, 28.2%, and 26.8%, respectively, versus 20.7% for placebo ( p = 0.033, 0.072, 0.201, 0.294 vs. placebo). Secondary efficacy endpoints (e.g. ≥50% responder rate, change from baseline in frequency of migraine/headache days, and percentage of severe migraines) had results favoring the three higher eptinezumab doses versus placebo. Eptinezumab was well tolerated and adverse event rates were similar to placebo. Conclusions The results of this trial demonstrate that eptinezumab appears effective and well-tolerated for the preventive treatment of chronic migraine and justifies the conduct of pivotal phase 3 trials for migraine prevention. Trial Registration ClinicalTrials.gov identifier: NCT02275117.

Background Previously published three-month placebo-controlled and one-year open-label clinical trial data have provided information on the efficacy and safety of erenumab. Methods Interim analysis was undertaken from an ongoing five-year open-label treatment phase after all patients completed three years in the open-label treatment phase or discontinued the study. Adult patients with episodic migraine enrolled in the open-label treatment phase initially received 70 mg erenumab monthly. A protocol amendment increased the dosage to 140 mg monthly to assess long-term safety of the higher dose. Safety and tolerability were assessed by monitoring adverse events, electrocardiograms, laboratory assessments, and vital signs. Results Of 383 patients enrolled in the open-label treatment phase, at data cutoff 235 (61.3%) remained in the study, all received 140 mg for ≥1 year. Median (Q1, Q3) exposure (70 or 140 mg) for all patients enrolled was 3.2 (1.3, 3.4) years. The most frequent adverse events (≥4.0/100 patient-years) were reported as viral upper respiratory tract infection, sinusitis, influenza, and back pain. Exposure-adjusted serious adverse event rates were 4.2/100 patient-years. There was no increase in cardiovascular events over time. Conclusions In this long-term study of a CGRP-receptor antibody, erenumab was found to be safe and well-tolerated with a spectrum and rate of adverse events consistent with shorter-term placebo-controlled studies. Trial registration ClinicalTrials.gov NCT01952574

Background: The otic ganglion (OG) is a cranial parasympathetic ganglion located in the infratemporal fossa under the foramen ovale (FO) and adjacent to the medial part of the mandibular nerve. Parasympathetic innervation of intracranial vessels from the OG has been shown both in animal and human models and evidence suggests that the OG plays an important role in the cranial vasomotor response. We review the evidence that positions the OG as a viable target for headache disorders. The OG is a small structure and not detectable on medical imaging. The FO is easily identifiable on CT scans and the mandibular nerve on MRI, hence, the position of the OG may be predicted if the mean distance from the FO is known. Objective: The objective is to describe the average distance between the FO and the OG in a sample of 18 infratemporal fossae from 21 cadavers. Methods: A total of 21 high definition photographs of 21 infratemporal fossae from 18 cadavers were analyzed. The distance between the inferior edge of the medial part of the FO to the OG was measured. Results: Four photographs of infratemporal fossae of four cadavers were excluded due to the inability to localize the inferior edge of the FO. A total of 15 infratemporal fossae from 17 cadavers were measured. The mean distance from the FO to the OG was 4.5 mm (SD 1.7), range 2.1–7.7 mm. Conclusions: We have described the average distance from the OG to an easily identifiable anatomical landmark that is visible in CT scans, the FO. This anatomical study may aid in the development of strategies to localize the OG in order to explore its role as a therapeutic target for headache disorders.

Background The Phase 3 REsearch Evaluating Migraine Prophylaxis Therapy (PREEMPT) trials demonstrated efficacy/tolerability of onabotulinumtoxinA for headache prevention in adults with chronic migraine. This post hoc analysis assessed time of onset of onabotulinumtoxinA after the first treatment in total and responder populations and consistency weekly through five treatment cycles. Methods In the 24-week, double-blind, placebo-controlled phase of PREEMPT, individuals were randomized 1:1 to onabotulinumtoxinA (155-195 U) or placebo every 12 weeks for two cycles. The primary pooled efficacy variable was change in headache days per 28 days at week 24. We assessed change in headache and migraine/probable migraine (hereafter migraine) days/week compared with baseline week 4. Results Baseline mean (SD) headache days/week (week 4 of baseline) for onabotulinumtoxinA (n = 688) and placebo (n = 696) were similar (4.8 [1.6] vs. 4.8 [1.6] days/week, respectively), as were migraine days/week (4.6 [1.7] vs. 4.6 [1.7] days/week). The effect of onabotulinumtoxinA on change in headache and migraine days/week was significantly greater than placebo at week 1, persisting from week 3 after the first treatment (−1.6 [2.2] vs. −1.1 [2.2] headache days/week [ p < 0.001] and −1.6 [2.2] vs. −1.1 [2.2] migraine days/week [ p < 0.001]). Headache and migraine days decreased in onabotulinumtoxinA responders beginning 1 week after treatment 1. Conclusions Treatment with onabotulinumtoxinA is associated with significant reductions in headache and migraine days/week at week 1, persisting after week 3, compared with placebo. Combined with earlier reports showing onabotulinumtoxinA treatment results in a persistent and progressive reduction in headache days over 56 weeks, it is suggested peak benefit may require multiple treatments. Trial registration number ClinicalTrials.gov: NCT00156910 and NCT00168428.