Small Molecule Calcitonin Gene-related Peptide Receptor Research Articles

US Real-World Effectiveness, Tolerability, and Healthcare Resource Utilization After Addition of Fremanezumab for Preventive Treatment in Patients Using Gepants for Acute Treatment of Migraine: Results From a Retrospective Chart Review.

Fremanezumab, a monoclonal antibody (mAb) targeting the calcitonin gene-related peptide (CGRP) pathway, and gepants, small molecule CGRP receptor antagonists, are both approved for the treatment of migraine or its symptoms. This study assessed effectiveness, tolerability, and migraine-related healthcare resource utilization (HCRU) after the addition of fremanezumab for preventive migraine treatment in patients using gepants for acute treatment. Data were extracted during a retrospective chart review from electronic medical records from the Dent Neurologic Institute. Eligible patients were≥18years old, using gepants (rimegepant or ubrogepant), who initiated fremanezumab between January 1, 2020, and May 1, 2021 (index date: date of fremanezumab initiation) and continued concomitant use of gepants and fremanezumab for≥1month (post-index; between 7-9months of follow-up). Outcomes included monthly migraine days (MMD), adverse events (AEs), reasons for discontinuation, and migraine-related HCRU. A total of 55 patients [female, 93%; mean (SD) age, 43.5 (13.5) years] met the inclusion criteria. All patients were diagnosed with chronic migraine. Patients had an average (SD) MMD of 15.8 (7.4) at the index date. Average (SE) change in MMD from index date to post-index was -6.5 (1.0) days (p<0.0001). Five patients (9.1%) experienced AEs post-index; no serious AEs (SAEs) were reported. The number of migraine-related medications used decreased from the index date to post-index by a mean of 0.6 for preventive medications (p=0.070), and 0.8 for acute medications (p=0.050). The number of outpatient office-based visits also decreased [mean (SD): 6months pre-index, 5.8 (4.4) vs. 6months post-index, 4.1 (4.0); p<0.0001]. The addition of fremanezumab preventively to gepants for acute migraine treatment was effective, resulted in fewer outpatient office visits, and yielded no SAEs or AEs that were novel to these migraine medication classes.

Population pharmacokinetic modeling of zavegepant, a calcitonin gene-related peptide receptor antagonist, in healthy adults and patients with migraine.

Zavegepant (ZAVZPRET™) is a high-affinity, selective, small-molecule calcitonin gene-related peptide receptor antagonist available for acute treatment of migraine in adults. A population pharmacokinetic analysis was performed to describe zavegepant plasma concentration-time course, characterize bioavailability, and identify covariates affecting zavegepant exposure. The model was developed and validated using data from 10 phase I clinical studies, wherein zavegepant was administered intravenously, intranasally, or orally to healthy adults and patients with migraine. Plasma concentration-time data were analyzed using nonlinear mixed-effects modeling. A three-compartment model with first-order elimination from the central compartment, and sequential zero- and first-order absorption best described the observed plasma concentration-time course of zavegepant. Bioavailability was 5.1% and 0.65% for intranasal and oral treatment, respectively; absorption rate constants were 5.8 and 0.8 h-1, respectively. Body weight-based empirical allometric scaling was applied using standard exponents (0.75 for clearance and 1 for volume of distribution). Age (range 18-71 years), race, ethnicity, sex, renal function, and co-administration of oral contraceptives or sumatriptan did not significantly change zavegepant pharmacokinetics. Moderate hepatic impairment (Child-Pugh score 7-9) or co-administration of rifampin decreased elimination clearance of oral zavegepant by ~40%. The zavegepant population pharmacokinetic model adequately characterized zavegepant concentration-time profiles, the bioavailability of intranasal and oral zavegepant, as well as the effect of intrinsic and extrinsic factors on zavegepant pharmacokinetics.

Assessment of pharmacokinetic and pharmacodynamic interactions between zavegepant and sumatriptan: A phase 1, randomized, placebo-controlled study in healthy adults.

To evaluate the pharmacodynamic (PD) and pharmacokinetic (PK) interactions between zavegepant and sumatriptan in healthy adults. Zavegepant is a high-affinity, selective, small-molecule calcitonin gene-related peptide receptor antagonist administered as a nasal spray approved in the United States for the acute treatment of migraine. Triptans, including sumatriptan, are a different class of drugs for acute migraine treatment and are associated with a risk of increased blood pressure (BP). Hence, it is important to study the drug-drug interactions between zavegepant and sumatriptan due to potential coadministration in clinical settings. This was a Phase 1, single-center, partially blind, randomized, placebo-controlled, single-arm study. Eligible participants were males aged ≥ 18 and ≤ 40 years or females aged ≥ 18 and ≤ 50 years. On Day 1, participants received sumatriptan 2 × 6 mg subcutaneous injections (1 h apart) and were then randomized (6:1 ratio) to receive zavegepant 2 × 10 mg nasal spray (1 in each nostril) or placebo on Days 2 and 3. On Day 4, zavegepant or placebo was coadministered with sumatriptan after the second sumatriptan injection. BP, PK, and safety were evaluated at pre-specified time points. Forty-two participants enrolled in the study received at least one dose of any treatment and were included in the safety analyses. Forty-one participants who completed the study were included in the BP and PK analyses. The mean (standard deviation) time-weighted average (TWA) of mean arterial pressure (MAP [sumatriptan+ zavegepant 87.2 (6.8) vs. sumatriptan 86.9 (6.0)]), diastolic BP (DBP [sumatriptan + zavegepant 72.3 (6.8) vs. sumatriptan 72.1 (6.2)]), and systolic BP (SBP [sumatriptan + zavegepant 116.8 (10.2) vs. sumatriptan 116.2 (8.6)]) did not change following zavegepant and sumatriptan coadministration on Day 4 compared to sumatriptan alone on Day 1. Statistical comparisons of the TWA of MAP, DBP, and SBP between sumatriptan and zavegepant coadministration and sumatriptan alone were similar; the differences observed were 0.04 mmHg for MAP (90% confidence interval [CI]: -0.69, 0.77 mmHg), 0.00 mmHg for DBP (90% CI: -0.76, 0.76 mmHg), and 0.33 mmHg for SBP (90% CI: -0.97, 1.63 mmHg). Sumatriptan PK after sumatriptan and zavegepant coadministration versus sumatriptan alone was similar; the comparison ratios were 102.5% (90% CI: 100.7%, 104.2%) for AUC0-inf and 104.1% (90% CI: 98.0%, 110.6%) for Cmax. A small difference in zavegepant PK exposure after sumatriptan and zavegepant coadministration versus zavegepant alone was not considered clinically relevant: the comparison ratios were 112.4% (90% CI: 103.4%, 122.3%) for AUC0-24 and 96.7% (90% CI: 88.9%, 105.2%) for Cmax. Overall, 90% (38/42) of participants experienced ≥ 1 treatment-emergent adverse event that was mild or moderate in severity. All treatments were generally safe and well tolerated. Coadministration of zavegepant with sumatriptan was safe and without PD or PK interactions in healthy adults.

Mass balance and pharmacokinetic characterization ofzavegepant in healthy male subjects.

Zavegepant, a high-affinity, selective, small-molecule calcitonin gene-related peptide receptor antagonist, is approved as a nasal spray for acute treatment of migraine in adults. This phase I, open-label, single-center, single-period, nonrandomized study in six healthy male subjects assessed mass balance recovery after a single 15-min intravenous (IV) infusion dose of carbon-14 ([14C])-zavegepant. Blood, urine, and fecal samples were collected over 192 h for analysis of zavegepant in plasma and urine; total radioactivity (TR) in plasma, whole blood, urine, and feces; and zavegepant metabolite profiling and structural identification in plasma, urine, and feces. An average of 96.6% of radioactivity administered was recovered in excreta. Most TR (mean 84.9%) was recovered in the feces, indicating that biliary/fecal elimination was the main route. Volume of distribution of zavegepant based on the terminal phase (129 L) was higher than total body water (42 L), indicating substantial distribution into tissue. Total plasma clearance of zavegepant (220 mL/min) is identical to whole blood clearance given the blood/plasma partition ratio of 1, lower than typical hepatic blood flow (1450 mL/min). The observed plasma terminal half-life of zavegepant was 6.8 h. Exposure to zavegepant accounted for ~90% of circulating plasma TR, suggesting that very low levels of uncharacterized circulating metabolites were present. Metabolite profiling did not identify any metabolites representing ≥10% of radioactivity in plasma, urine, or feces. A single IV infusion of 5 mg [14C]-zavegepant was well tolerated in healthy male subjects. Disposition findings of IV [14C]-zavegepant are applicable to the disposition of the approved zavegepant nasal spray.

Efficacy and safety of atogepant, a small molecule CGRP receptor antagonist, for the preventive treatment of migraine: a systematic review and meta-analysis

BackgroundMigraine is one of the most common diseases worldwide while current treatment options are not ideal. New therapeutic classes of migraine, the calcitonin gene-related peptide (CGRP) antagonists, have been developed and shown considerable effectiveness and safety. The present study aimed to systematically evaluate the efficacy and safety of atogepant, a CGRP antagonist, for migraine prophylaxis from the results of randomized controlled trials (RCTs).MethodsThe Cochrane Library, Embase, PubMed and https://www.clinicaltrials.gov/ were searched for RCTs that compared atogepant with placebo for migraine prophylaxis from inception of the databases to Feb 1, 2024. Outcome data involving efficacy and safety were combined and analyzed using Review Manager Software version 5.3 (RevMan 5.3). For each outcome, risk ratios (RRs) or standardized mean difference (SMD) were calculated.Results4 RCTs with a total of 2813 subjects met our inclusion criteria. The overall effect estimate showed that atogepant was significantly superior to placebo in terms of the reduction of monthly migraine (SMD − 0.40, 95% CI -0.46 to -0.34) or headache (SMD − 0.39, 95% CI -0.46 to -0.33) days, the reduction of acute medication use days (SMD − 0.45, 95% CI -0.51 to -0.39) and 50% responder rate (RR 1.66, 95% CI 1.46 to 1.89), while no dose-related improvements were found between different dosage groups. For the safety, significant number of patients experienced treatment-emergent adverse events (TEAEs) with atogepant than with placebo (RR 1.10, 95% CI 1.02–1.21) while there was no obvious difference between the five dosage groups. Most TEAEs involved constipation (RR 2.55, 95% CI 1.91–3.41), nausea (RR 2.19, 95% CI 1.67–2.87) and urinary tract infection (RR 1.49, 95% CI 1.05–2.11). In addition, a high dosage of atogepant may also increase the risk of treatment-related TEAEs (RR 1.64, 95% CI 1.02–2.63) and fatigue (RR 3.07, 95% CI 1.13–8.35).ConclusionsThis meta-analysis suggests that atogepant is effective and tolerable for migraine prophylaxis including episodic or chronic migraine compared with placebo. It is critical to weigh the benefits of different doses against the risk of adverse events in clinical application of atogepant. Longer and multi-dose trials with larger sample sizes are required to verify the current findings.

Safety of Rimegepant in Adults with Migraine and Cardiovascular Risk Factors: Analysis of a Multicenter, Long-Term, Open-Label Study.

Cardiovascular (CV) risk factors can limit treatment options for migraine. Rimegepant is an orally administered small-molecule calcitonin gene-related peptide receptor antagonist that does not induce vasoconstriction. The aim of these post hoc subgroup analyses was to assess the safety of rimegepant according to CV risk. In a multicenter, long-term, open-label, phase II/III safety study, participants with a history of 2-14 migraine attacks per month of moderate or severe pain intensity self-administered rimegepant 75 mg, orally, to treat migraine up to once daily for up to 52 weeks. Uncontrolled, unstable, or recently diagnosed CV disease was part of the exclusion criteria. Safety was assessed across subgroups according to number of CV risk factors (0, 1, or ≥ 2) and Framingham Risk Score (< 10% or ≥ 10%). Of 1800 treated participants, 28.8% had one CV risk factor and 12.1% had ≥ 2 CV risk factors; 7.0% had Framingham Risk Score ≥ 10%. Across the subgroups with 0, 1, and ≥ 2 CV risk factors and Framingham Risk Score < 10% and ≥ 10%, respectively, proportions of participants reporting adverse events (AEs; 59.6%, 61.4%, 62.2%, 59.9%, 67.5%) and serious AEs (2.7%, 2.5%, 2.3%, 2.6%, 2.4%) were consistent, and AEs leading to study drug discontinuation were low (1.9%, 3.1%, 5.5%, 2.5%, 4.8%). Rimegepant showed favorable safety and tolerability in adults with migraine and CV risk factors, including those with moderate to high CV risk. ClinicalTrials.gov NCT03266588.

Rimegepant orally disintegrating tablet 75 mg for acute treatment of migraine in adults from China: a subgroup analysis of a double-blind, randomized, placebo-controlled, phase 3 clinical trial

Background Rimegepant orally disintegrating tablet (ODT), an oral small-molecule calcitonin gene-related peptide receptor antagonist, is indicated for acute and preventive treatment of migraine in the United States and other countries. Previously, a large clinical trial assessed the efficacy and safety of rimegepant ODT 75 mg for the acute treatment of migraine in adults living in China or South Korea. A post hoc subgroup analysis of this trial was performed to evaluate the efficacy and safety of rimegepant for acute treatment of migraine in adults living in China.Methods Eligible participants were ≥ 18 years of age and had a ≥ 1-year history of migraine, with 2 to 8 attacks of moderate or severe pain intensity per month and < 15 headache days per month during the 3 months before screening. Participants self-administered rimegepant ODT 75 mg or matching placebo to treat a single migraine attack of moderate or severe pain intensity. The co-primary endpoints were pain freedom and freedom from the most bothersome symptom (MBS) at 2 h post-dose. Key secondary endpoints included pain relief at 2 h post-dose, ability to function normally at 2 h post-dose, use of rescue medication within 24 h post-dose, and sustained pain freedom from 2 to 24 h and 2 to 48 h post-dose. All p values were nominal. Safety was assessed via treatment-emergent adverse events (TEAEs), electrocardiograms, vital signs, and routine laboratory tests.ResultsOverall, 1075 participants (rimegepant, n = 538; placebo, n = 537) were included in the subgroup analysis. Rimegepant was more effective than placebo for the co-primary endpoints of pain freedom (18.2% vs. 10.6%, p = 0.0004) and freedom from the MBS (48.0% vs. 31.8%, p < 0.0001), as well as all key secondary endpoints. The incidence of TEAEs was comparable between the rimegepant (15.2%) and placebo (16.4%) groups. No signal of drug-induced liver injury was observed, and no study drug-related serious TEAEs were reported in the rimegepant group.ConclusionsA single dose of rimegepant 75 mg rimegepant was effective for the acute treatment of migraine in adults living in China, with safety and tolerability similar to placebo.Trial registration Clinicaltrials.gov NCT04574362 Date registered: 2020-10-05.Graphical

Preventive Treatment of Migraine.

This article describes strategies for the preventive treatment of migraine including the emerging role of calcitonin gene-related peptide (CGRP)-targeted therapies and introduces novel paradigms for the preventive treatment of migraine. Multiple migraine medications targeting CGRP have been introduced since 2018, including injectable monoclonal antibodies (ie, eptinezumab, erenumab, fremanezumab, and galcanezumab) and oral small-molecule CGRP receptor antagonists (ie, ubrogepant, rimegepant, atogepant, and zavegepant). With the exceptions of ubrogepant and zavegepant, which are approved only as acute treatments, all of these agents have demonstrated efficacy in the preventive treatment of migraine; the monoclonal antibodies and atogepant have evidence of effectiveness in adults with either episodic or chronic migraine. The safety and tolerability profiles of CGRP-targeted therapies in migraine are favorable. The goals of preventive migraine therapy include reducing the frequency, severity, duration, and disability associated with attacks, reducing the need for acute treatment and the risk of medication overuse, enhancing self-efficacy and health-related quality of life, and reducing headache-related distress and interictal burden. Six drugs targeting CGRP (four monoclonal antibodies and two gepants) are now available for the preventive treatment of episodic migraine in adults. The efficacy of CGRP-targeted medications in the acute and preventive treatment of migraine, together with good safety and tolerability, has led to the emergence of new approaches to preventive treatment.

Novel insight into atogepant mechanisms of action in migraine prevention.

Recently, we showed that while atogepant-a small-molecule calcitonin gene-related peptide (CGRP) receptor antagonist-does not fully prevent activation of meningeal nociceptors, it significantly reduces a cortical spreading depression (CSD)-induced early response probability in C fibres and late response probability in Aδ fibres. The current study investigates atogepant effect on CSD-induced activation and sensitization of high threshold (HT) and wide dynamic range (WDR) central dura-sensitive trigeminovascular neurons. In anaesthetized male rats, single-unit recordings were used to assess effects of atogepant (5 mg/kg) versus vehicle on CSD-induced activation and sensitization of HT and WDR trigeminovascular neurons. Single cell analysis of atogepant pretreatment effects on CSD-induced activation and sensitization of central trigeminovascular neurons in the spinal trigeminal nucleus revealed the ability of this small molecule CGRP receptor antagonist to prevent activation and sensitization of nearly all HT neurons (8/10 versus 1/10 activated neurons in the control versus treated groups, P = 0.005). In contrast, atogepant pretreatment effects on CSD-induced activation and sensitization of WDR neurons revealed an overall inability to prevent their activation (7/10 versus 5/10 activated neurons in the control versus treated groups, P = 0.64). Unexpectedly however, in spite of atogepant's inability to prevent activation of WDR neurons, it prevented their sensitization (as reflected their responses to mechanical stimulation of the facial receptive field before and after the CSD). Atogepant' ability to prevent activation and sensitization of HT neurons is attributed to its preferential inhibitory effects on thinly myelinated Aδ fibres. Atogepant's inability to prevent activation of WDR neurons is attributed to its lesser inhibitory effects on the unmyelinated C fibres. Molecular and physiological processes that govern neuronal activation versus sensitization can explain how reduction in CGRP-mediated slow but not glutamate-mediated fast synaptic transmission between central branches of meningeal nociceptors and nociceptive neurons in the spinal trigeminal nucleus can prevent their sensitization but not activation.

Atogepant: Mechanism of action, clinical and translational science.

Since the discovery of calcitonin gene-related peptide (CGRP) in 1982, its integral role in migraine pathophysiology, specifically migraine pain, has been demonstrated through cumulative scientific discoveries that have led to the development and approval of migraine-specific therapeutics. Today, eight drugs, including monoclonal antibodies and small molecule CGRP receptor antagonists, known as gepants, have received approval for acute or preventive treatment of migraine. The primary mechanism of these drugs is to block CGRP signaling, thus preventing CGRP-mediated nociception and neurogenic inflammation. Here, we focus on atogepant, a highly potent and selective gepant and the first and only oral medication approved for the preventive treatment of both episodic and chronic migraine in adults. In this article, we summarize the role of CGRP in migraine pathophysiology and the mechanism of action of atogepant. In addition, we provide an overview of atogepant's pharmacology and the key clinical trials and outcomes that have demonstrated the safety and efficacy of atogepant.

Ubrogepant: Mechanism of action, clinical and translational science.

In recent years, the treatment of migraine has experienced a breakthrough in the development of drugs that target the calcitonin gene-related peptide (CGRP) signaling pathway. Monoclonal antibodies against the receptor or ligand have been developed for the preventive treatment of migraine; whereas, orally administered small molecule CGRP receptor antagonists, called gepants, have been developed for both acute and/or preventive treatment. Both modalities have demonstrated safe and effective treatment of migraine, reducing the number of migraine days for patients as well as reducing symptoms and improving patient function and overall quality of life. Here, we provide an abridged review of ubrogepant, an oral CGRP receptor antagonist, approved for the acute treatment of migraine. We briefly summarize the role of CGRP in migraine pathophysiology, describing the mechanism of action of ubrogepant in the context of this pathway, the clinical pharmacology properties and the clinical development and outcomes, including safety, efficacy, pharmacokinetics, and pharmacodynamics, that supported ubrogepant's approval.

Calcitonin gene-related peptide receptor antagonism reduces motion sickness indicators in mouse migraine models.

Migraine and vestibular migraine are disorders associated with a heightened motion sensitivity that provoke symptoms of motion-induced nausea and motion sickness. VM affects ∼3% of adults in the USA and affects three-fold more women than men. Triptans (selective serotonin receptor agonists) relieve migraine pain but lack efficacy for vertigo. Murine models of photophobia and allodynia have used injections of calcitonin gene-related peptide (CGRP) or other migraine triggers, such as sodium nitroprusside (SNP), to induce migraine sensitivities in mice to touch and light. Yet, there is limited research on whether these triggers affect motion-induced nausea in mice, and whether migraine blockers can reduce these migraine symptoms. We hypothesized that systemic delivery of CGRP or SNP will increase motion sickness susceptibility and motion-induced nausea in mouse models, and that migraine blockers can block these changes induced by systemically delivered CGRP or SNP. We investigated two measures of motion sickness assessment [motion sickness index (MSI) scoring and motion-induced thermoregulation] after intraperitoneal injections of either CGRP or SNP in C57BL/6J mice. The drugs olcegepant, sumatriptan and rizatriptan were used to assess the efficacy of migraine blockers. MSI measures were confounded by CGRP's effect on gastric distress. However, analysis of tail vasodilatations as a surrogate for motion-induced nausea was robust for both migraine triggers. Only olcegepant treatment rescued tail vasodilatations. These preclinical findings support the use of small molecule CGRP receptor antagonists for the treatment of motion-induced nausea of migraine, and show that triptan therapeutics are ineffective against motion-induced nausea of migraine.Trial Registration: Not Applicable.

Blocking the CGRP Receptor: Differences across Human Vascular Beds.

Multiple drugs targeting the calcitonin gene-related peptide (CGRP) receptor have been developed for the treatment of migraine. Here, the effect of the small-molecule CGRP receptor antagonist zavegepant (0.1 nM-1 µM) on CGRP-induced relaxation in isolated human coronary arteries (HCAs) was investigated. A Schild plot was constructed and a pA2 value was calculated to determine the potency of zavegepant. The potency and Schild plot slopes of atogepant, olcegepant, rimegepant, telcagepant, ubrogepant and zavegepant in HCAs and human middle meningeal arteries (HMMAs), obtained from our earlier studies, were compared. Zavegepant shifted the concentration-response curve to CGRP in HCAs. The corresponding Schild plot slope was not different from unity, resulting in a pA2 value of 9.92 ± 0.24. No potency difference between HCAs and HMMAs was observed. Interestingly, olcegepant, atogepant and rimegepant, with a Schild plot slope < 1 in HCAs, were all >1 log unit more potent in HMMAs than in HCAs, while telcagepant, ubrogepant and zavegepant, with a Schild plot slope not different from unity, showed similar (<1 log difference) potency across both tissues. As a Schild plot slope < 1 may point to the involvement of multiple receptors, it is important to further identify the receptors involved in the relaxation to CGRP in HCAs, which may be used to improve the cardiovascular safety of future antimigraine drugs.

Rimegepant 75mg in Subjects With Hepatic Impairment: Results of a Phase 1, Open-Label, Single-Dose, Parallel-Group Study.

Rimegepant is a small-molecule calcitonin gene-related peptide receptor antagonist (gepant) with demonstrated efficacy and safety in the acute and preventive treatment of migraine. Here, we report the pharmacokinetics and safety of a single 75-mg oral dose of rimegepant in subjects with severe, moderate, or mild hepatic impairment and matched healthy subjects from an open-label, single-dose, 4-group phase 1 study. Thirty-six subjects aged 41-71 years were enrolled, including 6 each with severe, moderate, or mild hepatic impairment and 18 healthy subjects. All subjects completed the study. A <20% increase in total and unbound pharmacokinetics was observed in subjects with mild hepatic impairment and ≤65% increase with moderate hepatic impairment versus matched healthy controls. Total and unbound systemic exposure increased 2.0- and 3.9-fold in the severe hepatic impairment group. In subjects with severe hepatic impairment, geometric mean ratios (severe impairment/controls) for total concentrations were 202.2% for area under the plasma concentration-time curve from time 0 to the last quantifiable concentration, 202.2% for area under the plasma concentration-time curve from time 0 to infinity, and 189.1% for maximum observed plasma concentration. Corresponding geometric mean ratios using unbound concentrations were 388.8% and 388.7%, respectively. Three (8.3%) subjects reported 4 treatment-emergent adverse events. Rimegepant is not recommended for use in adults with severe hepatic impairment.

Calcitonin gene relating peptide inhibitors in combination for migraine treatment: A mini-review.

The discovery of calcitonin gene-related peptide (CGRP) and its role in migraine pathophysiology has led to advances in the treatment of migraine. Since 2018, the Food and Drug Administration (FDA) has approved four monoclonal antibody (mab) therapies targeting either the CGRP ligand or receptor and 3 oral small molecule CGRP receptor antagonists. These targeted therapies have been shown to be safe and effective for either preventive or acute treatment of migraine in adults. Given their efficacy and tolerability profile, CGRP inhibitors have revolutionized the approach to migraine treatment. Theoretically, combining therapies within this therapeutic class could lead to more CGRP blockade and, subsequently, improved patient outcomes. There are providers currently combining CGRP therapies in clinical practice. However, limited data are available regarding the efficacy and safety of this practice. This mini-review provides a summary of available data and poses important considerations when combining CGRP therapies for migraine treatment.

New migraine prophylactic drugs: Current evidence and practical suggestions for non-responders to prior therapy

Monoclonal antibodies against calcitonin gene-related peptide (CGRP) or its receptor (anti-CGRP(-R) mAbs) and small-molecule CGRP receptor antagonists (gepants) are new mechanism-based prophylactic drugs developed to address the unmet needs of pre-existing migraine prophylactic medications. However, several uncertainties remain in their real-world applications. This is a narrative review of the literature on the use of CGRP-targeting novel therapeutics in specific situations, including non-responders to prior therapy, combination therapy, switching, and treatment termination. In the case of lack of available literature, we made suggestions based on clinical reasoning. High-quality evidence supports the use of all available anti-CGRP(-R) mAbs (erenumab, galcanezumab, fremanezumab, and eptinezumab) in non-responders to prior therapy. There is insufficient evidence to support or reject the efficacy of combining CGRP(-R) mAbs or gepants with oral migraine prophylactic agents or botulinum toxin A. Switching from one CGRP(-R) mAb to another might benefit a fraction of patients. Currently, treatment termination depends on reimbursement policies, and the optimal mode of termination is discussed. New prophylactic drugs that target the CGRP pathway are promising treatment options for patients with difficult-to-treat migraine. Individualized approaches using a combination of new substances with oral prophylactic drugs or botulinum toxin A, switching between new drugs, and adjusting treatment duration could enhance excellence in practice.

Commentary: Constipation caused by anti-calcitonin gene-related peptide migraine therapeutics explained by antagonism of calcitonin gene-related peptide's motor-stimulating and prosecretory function in the intestine.

Calcitonin gene-related peptide (CGRP) pathway-targeted treatments have been shown to be efficacious in the prevention of episodic and chronic migraine. Currently approved therapies include monoclonal antibodies (mAbs) that target CGRP (eptinezumab, fremanezumab, and galcanezumab) and the CGRP receptor (erenumab), and small molecule CGRP receptor antagonists (atogepant and rimegepant). While CGRP pathway-targeted treatments are generally well-tolerated, in a review article by Holzer and Holzer-Petsche published in the January 2022 issue of Frontiers in Physiology the authors discussed the role of the CGRP pathway in gastrointestinal physiology, with a specific focus on constipation associated with the use of CGRP pathway-targeted treatments. The authors state that real-world surveys have shown constipation to be a "major adverse event" reported in "more than 50% of patients treated with erenumab, fremanezumab or galcanezumab." As described in the current commentary, the limited data from the cited references in the review article by Holzer and Holzer-Petsche do not support that statement.

Characterization of erenumab and rimegepant on calcitonin gene-related peptide induced responses in Xenopus Laevis oocytes expressing the calcitonin gene-related peptide receptor and the amylin-1 receptor

BackgroundThe clinical use of calcitonin gene-related peptide receptor (CGRP-R) antagonists and monoclonal antibodies against CGRP and CGRP-R has offered new treatment possibilities for migraine patients. CGRP activates both the CGRP-R and structurally related amylin 1 receptor (AMY1-R). The relative effect of erenumab and the small-molecule CGRP-R antagonist, rimegepant, towards the CGRP-R and AMY-R needs to be further characterized.MethodsThe effect of CGRP and two CGRP-R antagonists were examined in Xenopus laevis oocytes expressing human CGRP-R, human AMY1-R and their subunits.ResultsCGRP administered to receptor expressing oocytes induced a concentration-dependent increase in current with the order of potency CGRP-R> > AMY1-R > calcitonin receptor (CTR). There was no effect on single components of the CGRP-R; calcitonin receptor-like receptor and receptor activity-modifying protein 1. Amylin was only effective on AMY1-R and CTR. Inhibition potencies (pIC50 values) for erenumab on CGRP induced currents were 10.86 and 9.35 for CGRP-R and AMY1-R, respectively. Rimegepant inhibited CGRP induced currents with pIC50 values of 11.30 and 9.91 for CGRP-R and AMY1-R, respectively.ConclusionOur results demonstrate that erenumab and rimegepant are potent antagonists of CGRP-R and AMY1-R with 32- and 25-times preference for the CGRP-R over the AMY1-R, respectively. It is discussed if this difference in affinity between the two receptors is the likely reason why constipation is a common and serious adverse effect during CGRP-R antagonism but less so with CGRP binding antibodies.

Calcitonin gene-related peptide (CGRP) is a key molecule released in acute migraine attacks-Successful translation of basic science to clinical practice.

Migraine is a highly prevalent neurovascular disorder afflicting more than 15% of the global population. Nearly three times more females are afflicted by migraine in the 18–50 years age group, compared to males. Migraine attacks are most often sporadic, but a subgroup of individuals experience a gradual increase in frequency over time; among these, up to 1%–2% of the global population develop chronic migraine. Although migraine symptoms have been known for centuries, the underlying mechanisms remain largely unknown. Two theories have dominated the current thinking—a neurovascular theory and a central neuronal theory with the origin of the attacks in the hypothalamus. During the last decades, the understanding of migraine has markedly advanced. This is supported by the early seminal demonstration of the trigeminovascular reflex 35 years ago and the insight that calcitonin gene‐related peptide (CGRP) is a key molecule released in acute migraine attacks. The more recent findings that gepants, small molecule CGRP receptor blockers, and monoclonal antibodies generated against CGRP, or its canonical receptor are useful for the treatment of migraine, are other important issues. CGRP has been established as a key molecule in the neurobiology of migraine. Moreover, monoclonal antibodies to CGRP or the CGRP receptor represent a breakthrough in the understanding of migraine pathophysiology and have emerged as an efficacious prophylactic treatment for patients with severe migraine with excellent tolerability. This review describes the progression of research to reach the clinical usefulness of a large group of molecules that have in common the interaction with CGRP mechanisms in the trigeminal system to alleviate the burden for individuals afflicted by migraine.

P-Glycoprotein and Breast Cancer Resistance Protein Transporter Inhibition by Cyclosporine and Quinidine on the Pharmacokinetics of Oral Rimegepant in Healthy Subjects.

Rimegepant (Nurtec ODT)—an orally administered, small‐molecule calcitonin gene–related peptide receptor antagonist indicated for the acute and preventive treatment of migraine—is a substrate for both the P‐glycoprotein and breast cancer resistance protein transporters in vitro. We evaluated the effects of concomitant administration of strong inhibitors of these transporters on the pharmacokinetics of rimegepant in healthy subjects. This single‐center, open‐label, randomized study was conducted in 2 parts, both of which were 2‐period, 2‐sequence, crossover studies. Part 1 (n = 15) evaluated the effect of a single oral dose of 200‐mg cyclosporine, a strong inhibitor of the P‐glycoprotein and breast cancer resistance protein transporters, on the pharmacokinetics of rimegepant 75 mg. Part 2 (n = 12) evaluated the effect of a single oral dose of 600‐mg quinidine, a strong selective P‐glycoprotein transporter, on the pharmacokinetics of rimegepant 75 mg. Coadministration with cyclosporine showed an increase in rimegepant area under the plasma concentration–time curve from time 0 to infinity and maximum observed concentration based on geometric mean ratios (90% confidence intervals [CIs]) of 1.6 (1.49‐1.72) and 1.41 (1.27‐1.57), respectively, versus rimegepant alone. Coadministration with quinidine showed an increase in rimegepant area under the plasma concentration–time curve from time 0 to infinity and maximum observed concentration geometric mean ratios (90% CIs) of 1.55 (1.40‐1.72) and 1.67 (1.46‐1.91), respectively, versus rimegepant alone. Strong P‐glycoprotein inhibitors (cyclosporine, quinidine) increased rimegepant exposures (>50%, <2‐fold). In parts 1 and 2, rimegepant coadministration was well tolerated and safe. The similar effect of cyclosporine and quinidine coadministration on rimegepant exposure suggests that inhibition of breast cancer resistance protein inhibition may have less influence on rimegepant exposure.