CGRP Modulating Therapies: An Update.

INTRODUCTION: Calcitonin-gene related peptide (CGRP) is a vasoactive neuropeptide involved in the pathophysiology ofmigraine. CGRP has been targeted for both preventive and acute treatment of migraine. OBJECTIVE: Provide a summary of the most clinically relevant literature surrounding CGRP modulating therapies. METHODS: This update on CGRP modulating therapies includes articles selected as most clinically relevant by theauthors. CONCLUSION: CGRP modulating therapies are an exciting new addition to migraine treatment given their safety andtolerability. Additionally, compared to traditional migraine preventive medication these treatments are migrainespecific.Further real-world and clinical data is ongoing to better understand these treatments that continue to gainfavor in the management of migraine.

Pharmacologic characterization of atogepant: A potent and selective calcitonin gene-related peptide receptor antagonist.

BACKGROUND: The trigeminal sensory neuropeptide calcitonin gene-related peptide (CGRP) is identified as an essential element in migraine pathogenesis. METHODS: In vitro and in vivo studies evaluated pharmacologic properties of the CGRP receptor antagonist atogepant. Radioligand binding using 125I-CGRP and cyclic adenosine monophosphate (cAMP) accumulation assays were conducted in human embryonic kidney 293 cells to assess affinity, functional potency and selectivity. Atogepant in vivo potency was assessed in the rat nitroglycerine model of facial allodynia and primate capsaicin-induced dermal vasodilation (CIDV) pharmacodynamic model. Cerebrospinal fluid/brain penetration and behavioral effects of chronic dosing and upon withdrawal were evaluated in rats. RESULTS: Atogepant exhibited high human CGRP receptor-binding affinity and potently inhibited human α-CGRP-stimulated cAMP responses. Atogepant exhibited significant affinity for the amylin1 receptor but lacked appreciable affinities for adrenomedullin, calcitonin and other known neurotransmitter receptor targets. Atogepant dose-dependently inhibited facial allodynia in the rat nitroglycerine model and produced significant CIDV inhibition in primates. Brain penetration and behavioral/physical signs during chronic dosing and abrupt withdrawal were minimal in rats. CONCLUSIONS: Atogepant is a competitive antagonist with high affinity, potency and selectivity for the human CGRP receptor. Atogepant demonstrated a potent, concentration-dependent exposure/efficacy relationship between atogepant plasma concentrations and inhibition of CGRP-dependent effects.

The Pharmacokinetics, Safety, and Tolerability of Rimegepant 75 mg Are Similar in Elderly and Nonelderly Adults: A Phase 1, Open-Label, Parallel-Group, Single-Dose Study.

Rimegepant is a small-molecule calcitonin gene-related peptide receptor antagonist approved for the acute treatment of migraine ± aura and preventive treatment of migraine in adults. The pharmacokinetics of rimegepant in elderly and nonelderly subjects were evaluated. In an open-label Phase 1 study, 14 elderly (aged 65 years or older) and 14 nonelderly (aged 18 to less than 45 years) subjects each received a single oral dose of rimegepant 75 mg. Blood samples were collected before dosing and through 96 hours after dosing. The pharmacokinetic parameters of rimegepant after a single dose were similar in both age groups. Geometric least-squares mean ratios (elderly/nonelderly) of the natural log-transformed maximum observed plasma concentration and natural log-transformed area under the plasma concentration-time curve from time 0 extrapolated to infinity were 96.6 and 104.6, respectively. Eight (28.6%) subjects (4 elderly, 4 nonelderly) experienced 1 or more adverse events (AEs); all AEs were mild in intensity, and no serious AEs or AEs leading to discontinuation were reported. Following a single 75-mg dose of oral rimegepant, pharmacokinetic parameters were similar in elderly and nonelderly adults; no dose adjustment is warranted in elderly subjects.

Antinociceptive effect of the calcitonin gene-related peptide receptor antagonist BIBN4096BS in mice with bacterial cystitis.

Patients with urinary tract infections (UTIs) suffer from urinary frequency, urgency, dysuria, and suprapubic pain, but the mechanisms by which bladder afferents sense the presence of uropathogens and encode this information is not well understood. Calcitonin gene-related peptide (CGRP) is a 37-mer neuropeptide found in a subset of bladder afferents that terminate primarily in the lamina propria. Here, we report that the CGRP receptor antagonist BIBN4096BS lessens lower urinary tract symptoms and prevents the development of pelvic allodynia in mice inoculated with uropathogenic Escherichia coli (UPEC) without altering urine bacterial loads or the host immune response to the infection. These findings indicate that CGRP facilitates the processing of noxious/inflammatory stimuli during UPEC infection. Using fluorescent in situ hybridization, we identified a population of suburothelial fibroblasts in the lamina propria, a region where afferent fibers containing CGRP terminate, that expresses the canonical CGRP receptor components Calcrl and Ramp1. We propose that these fibroblasts, in conjunction with CGRP+ afferents, form a circuit that senses substances released during the infection and transmit this noxious information to the central nervous system.NEW & NOTEWORTHY Afferent C fibers release neuropeptides including calcitonin gene-related peptide (CGRP). Here, we show that the specific CGRP receptor antagonist, BIBN409BS, ameliorates lower urinary tract symptoms and pelvic allodynia in mice inoculated with uropathogenic E. coli. Using fluorescent in situ hybridization, we identified a population of suburothelial fibroblasts in the lamina propria that expresses the canonical CGRP receptor. Our findings indicate that CGRP contributes to the transmission of nociceptive information arising from the bladder.

Effects of rimegepant 75 mg daily on the pharmacokinetics of a combined oral contraceptive containing ethinyl estradiol and norgestimate in healthy female participants.

OBJECTIVE: To assess the effect of single and multiple doses of rimegepant 75 mg dose on the pharmacokinetics of an oral contraceptive containing ethinyl estradiol (EE)/norgestimate (NGM) in healthy females of childbearing potential or non-menopausal females with tubal ligation. BACKGROUND: Females of childbearing age experience the highest prevalence of migraine and frequently inquire about the concomitant use of anti-migraine medications and contraceptives. Rimegepant, a calcitonin gene-related peptide receptor antagonist, demonstrated efficacy and safety for treating an acute migraine attack and preventing migraine. METHODS: This open-label, single-center, phase 1, drug-drug interaction study explored the effects of rimegepant 75 mg daily dose on the pharmacokinetics of an oral contraceptive containing EE/NGM 0.035 mg/0.25 mg in healthy females of childbearing potential or non-menopausal females with tubal ligation. During cycles 1 and 2, participants received EE/NGM once daily for 21 days followed by placebo tablets with inactive ingredients for 7 days. Rimegepant was administered during only cycle 2 for 8 days, from days 12 through 19. The primary endpoint was the effect of single and multiple doses of rimegepant on the pharmacokinetics of EE and norelgestromin (NGMN), an active metabolite of NGM, at steady state, including area under the concentration-time curve for 1 dosing interval (AUC0-τ,ss ) and maximum observed concentration (Css[max] ). RESULTS: The study enrolled 25 participants, with pharmacokinetic data assessed for 20 participants. A single 75 mg dose of rimegepant co-administered with EE/NGM increased exposures of EE and NGMN by ≤16% (geometric mean ratio [GMR], 1.03; 90% confidence interval [CI], 1.01-1.06; and GMR, 1.16; 90% CI, 1.13-1.20, respectively). After 8 days of co-administering EE/NGM with rimegepant, EE pharmacokinetic parameters, AUC0-τ,ss and Css(max) , increased by 20% (GMR, 1.20; 90% CI, 1.16-1.25) and 34% (GMR, 1.34; 90% CI, 1.23-1.46), respectively, and NGMN pharmacokinetic parameters increased by 46% (GMR, 1.46; 90% CI, 1.39-1.52) and 40% (GMR, 1.40; 90% CI, 1.30-1.51), respectively. CONCLUSIONS: The study identified modest elevations in overall EE and NGMN exposures after multiple doses of rimegepant, but these elevations are unlikely to be clinically relevant in healthy females with migraine.

Rimegepant 75 mg 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.

Raynaud's phenomenon associated with calcitonin gene-related peptide receptor antagonists case report.

BACKGROUND: Calcitonin gene-related peptide (CGRP) is a potent vasodilator that regulates the cerebrovascular and peripheral circulation. A new class of migraine therapies decreases CGRP through various mechanisms. One unknown off-target effect is the impact decreasing CGRP will have on the peripheral circulation. The following cases report new onset Raynaud's phenomenon (RP) following the use of CGRP receptor antagonists (-gepants) for both the acute and preventive treatment of migraine. These cases describe the development of RP in two individuals after using each of the currently available gepant medications. To our knowledge these are the first cases reported of RP associated with the use of gepants. RP has previously been reported in association with monoclonal antibodies to the CGRP ligand and CGRP receptor indicated in the prevention of migraine. CASE PRESENTATION: One case involved oral CGRP receptor antagonists for acute treatment inducing RP. In this case, rimegepant and ubrogepant used separately for different migraine attacks each led to RP in the digits. The other case involved oral CGRP receptor antagonist, atogepant, used as a preventive treatment and induced RP in the digits. This patient had a prior history of areolar tissue RP while breastfeeding, but never in her fingers. In both cases, the offending medications were discontinued, and the patients reported no further episodes of RP. CONCLUSION: Two cases are reported of people with migraine with new onset digital RP while taking CGRP receptor antagonists (rimegepant, ubrogepant, atogepant) for acute and preventive treatment.

Calcitonin gene-related peptide (CGRP) receptor antagonists for the acute treatment of migraines in adults.

Migraine headaches are widespread, debilitating and considered a main cause of disability worldwide. Symptoms of migraines include unilateral, pulsating pain that can last for hours to days, frequently associated with photophobia and phonophobia, nausea, or vomiting, and often aggravated by physical activity. The Canadian Headache Society and American Headache Society guidelines suggest strong evidence of the efficacy of triptans, acetaminophen, aspirin, diclofenac sodium, naproxen and ibuprofen for the acute treatment of migraines. The use of calcitonin gene-related peptide (CGRP) antagonists for the treatment and prevention of migraines has been gaining utilization since the approval of the first agent in this class in 2018. There are increasing available options for the acute treatment of migraines. The purpose of this article is to provide a narrative review of the pharmacological and clinical characteristics of ubrogepant and rimegepant and to discuss their implications for use.

A Comprehensive Review of Zavegepant as Abortive Treatment for Migraine.

Migraine headache is a widespread and complex neurobiological disorder that is characterized by unilateral headaches that are often accompanied by photophobia and phonophobia. Migraine is one of the leading chief complaints in the emergency department with negative impacts on quality of life and activities of daily living. The high number of emergency presentations also results in a significant economic burden. Its risk factors include family history, genetics, sex, race, socioeconomics, the existence of comorbid conditions, and level of education. Triggers include stress, light, noise, menstruation, weather, changes in sleep pattern, hunger, dehydration, dietary factors, odors, and alcohol. The International Headache Society has defined criteria for the diagnosis of migraine with and without aura. The pathophysiology of migraine headaches is multifactorial so there are a variety of treatment approaches. The current treatment approach includes abortive medications and prophylactic medications. Abortive medications include the first-line treatment of triptans, followed by ergot alkaloids, and calcitonin gene-related peptide (CGRP) receptor antagonists along with supplemental caffeine and antiemetics. Trigeminal afferents from the trigeminal ganglion innervate most cranial tissues and many areas of the head and face. These trigeminal afferents express certain biomarkers such as calcitonin gene-related peptide (CGRP), substance P, neurokinin A, and pituitary adenylate cyclase-activating polypeptide that are important to the pain and sensory aspect of migraines. In this comprehensive review, we discuss Zavegepant, a calcitonin gene-related peptide receptor antagonist, as a new abortive medication for migraine headaches.

Functionality, satisfaction, and global impression of change with ubrogepant for the acute treatment of migraine in triptan insufficient responders: a post hoc analysis of the ACHIEVE I and ACHIEVE II randomized trials.

BACKGROUND: Triptans are the first-line option for the acute treatment of migraine attacks; however, triptans are contraindicated in people with certain underlying cardiovascular risk factors and are associated with inadequate efficacy or poor tolerability in some individuals. Ubrogepant is an oral calcitonin gene-related peptide receptor antagonist approved for the acute treatment of migraine. METHODS: This post hoc analysis of the phase 3 ACHIEVE trials examined the impact of ubrogepant on the Functional Disability Scale (FDS), satisfaction with medication, and Patient Global Impression of Change (PGIC) in participants who were self-reported triptan insufficient responders (TIRs), defined as those who are unable to take triptans due to contraindications, tolerability issues, or insufficient efficacy. Responder definitions for the FDS, satisfaction measures, and PGIC were based on qualitative interpretation of the respective response options for the pooled ubrogepant 50 mg and placebo groups. RESULTS: In the pooled analysis population (n = 1799), 451 (25%) participants were TIRs, with most (80%) reporting insufficient efficacy with triptan use. A significantly higher proportion of TIRs treated with ubrogepant vs placebo reported being able to function normally from 2 to 8 h post dose (P < 0.05). Notably, significance was demonstrated at the time of the primary outcome assessments (2 h post dose), where rates of normal function were 38% for ubrogepant vs 29% for placebo (P = 0.048). A greater proportion of TIRs in the ubrogepant arm vs the placebo arm were satisfied with treatment at 2 (33% vs 21%, P = 0.006) and 24 h (58% vs 28%, P < 0.001) and indicated that their migraine improved at 2 h vs placebo (30% vs 18%, P = 0.006). Results were generally similar in the insufficient efficacy subpopulation of TIRs as in the overall TIRs group. Ubrogepant was safe and well tolerated in TIRs, with no new safety signals identified. CONCLUSIONS: In people with migraine who are TIRs, individuals treated with ubrogepant had favorable 2-h outcomes, as measured by the FDS, satisfaction with medication, and PGIC, compared with placebo. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02828020 (ACHIEVE I), registered July 11, 2016; NCT02867709 (ACHIEVE II), registered August 16, 2016.

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.

Evaluation of the Pharmacokinetic Interaction and Safety of Ubrogepant Coadministered With Esomeprazole Magnesium.

Ubrogepant is a calcitonin gene-related peptide receptor antagonist for the acute treatment of migraine. Esomeprazole magnesium increases intragastric pH, which may affect oral ubrogepant absorption. This open-label, nonrandomized, crossover trial evaluated esomeprazole magnesium's impact on the pharmacokinetics and safety of coadministered ubrogepant in healthy adults. Participants received ubrogepant 100 mg on day 1, esomeprazole magnesium 40 mg on days 9 to 13, and ubrogepant 100 mg with esomeprazole magnesium 40 mg on day 14. No effect on ubrogepant pharmacokinetics was concluded if 90% confidence intervals of geometric mean ratios were within 80% to 125% for comparison of pharmacokinetic parameters between ubrogepant + esomeprazole magnesium versus ubrogepant alone. Thirty participants enrolled (mean age, 31.7 years; 53.3% males). Ubrogepant peak plasma concentration (Cmax ) decreased 23%, time to Cmax increased by 1.5 hours, and area under the plasma concentration-time curve was reduced by ≈10% when coadministered with esomeprazole magnesium versus ubrogepant alone. The 90% confidence interval of the geometric mean ratio for Cmax did not fall within the 80% to 125% equivalence range, but the decrease was not considered clinically meaningful. Esomeprazole magnesium coadministered with ubrogepant did not increase the incidence rate of treatment-emergent adverse events, and interactions between the medications are likely to have limited clinical relevance.

Optimal Dose of Erenumab for Preventive Treatment of Episodic Migraine: A Systematic Review and Meta-Analysis.

BACKGROUND: Erenumab is a novel monoclonal calcitonin gene-related peptide receptor antibody that is used for the preventive treatment of migraine. OBJECTIVES: This study aimed to evaluate the overall safety, efficacy, and dose-response relationship of erenumab in patients with episodic migraine and patients with prior migraine treatment failures. METHODS: We searched randomized clinical trials on PUBMED, EMBASE database, and Cochrane Library database. A pair-wise meta-analysis and Bayesian network analysis were performed. RESULTS: For efficacy outcomes, the network meta-analysis suggests that in comparison to erenumab 70 mg, participants who received erenumab 140 mg reported a significant decrease in monthly acute Migraine-Specific Medication Days (MSMD) and 50% increase in response rate, and erenumab was most likely to be ranked first for Monthly Migraine Days (MMD), MSMD, and 50% response rate. For safety outcomes, the network meta-analysis has found no significant difference between the 70 mg group and the 140 mg group measured by adverse events and serious adverse events. In the 140 mg erenumab group, a significant decreased in MMD and MSMD and 50% and 75% increased in response rate were reported in patients with ≥ 2 treatment failures compared to placebo. For safety outcomes, no significant difference was found between the 140 mg erenumab group and the placebo group. CONCLUSION: Erenumab was effective in patients with episodic migraine. A total of 140 mg erenumab was associated with better efficacy outcomes without any increased risk for developing adverse events compared to 70 mg erenumab. Furthermore, 140 mg erenumab was effective in patients with prior migraine treatment failures.

A Single Supratherapeutic Dose of Atogepant Does Not Affect Cardiac Repolarization in Healthy Adults: Results From a Randomized, Single-Dose, Phase 1 Crossover Trial.

Atogepant is a selective, oral calcitonin gene-related peptide receptor antagonist in development for preventive treatment of migraine. This randomized, double-blind, phase 1 crossover study evaluated the cardiac repolarization effect of a single supratherapeutic (300 mg) atogepant dose vs placebo in healthy adults. Moxifloxacin 400 mg was the open-label active control. The primary end point was a change from baseline in Fridericia-corrected QT intervals (ΔQTcF). Sixty participants were randomized to atogepant 300 mg, placebo, and moxifloxacin; 59 (98.3%) completed all interventions. Assay sensitivity was confirmed: lower 90% confidence interval limit for QTcF interval change from baseline (ΔΔQTcF) for moxifloxacin was >5 millisecond vs placebo at prespecified 2-, 3-, and 4-hour time points. Following single-dose atogepant 300 mg, mean atogepant ΔΔQTcF and upper 90% confidence interval limits were lower than the 10-millisecond threshold at all time points. Atogepant mean peak plasma concentration was 3197 ng/mL, area under the concentration-time curve from time 0 to time t was 16 640 ng • h/mL, area under the concentration-time curve from time 0 to 24 hours was 16 607 ng • h/mL, and median time to peak plasma concentration was 2.1 hours. The incidence of adverse events was low; no serious adverse events or elevations of liver enzymes were reported. Overall, a single supratherapeutic dose of atogepant was safe and did not impact cardiac repolarization in healthy participants.

Efficacy of ubrogepant based on prior exposure and response to triptans: A post hoc analysis.

OBJECTIVE: To determine the potential efficacy of ubrogepant for acute treatment of migraine based on historical experience with triptans. BACKGROUND: Although triptans have improved migraine treatment, their efficacy and tolerability may limit their utility in some individuals. Ubrogepant is a small-molecule, oral calcitonin gene-related peptide receptor antagonist approved by the Food and Drug Administration for acute treatment of migraine in adults. METHODS: This post hoc analysis of pooled data from the pivotal trials ACHIEVE I and II, identically designed, randomized, double-blind, phase 3, single-attack trials of ubrogepant in adults with a history of migraine with/without aura, examined the efficacy and tolerability of ubrogepant 50 mg versus placebo based on participants' historical experience with triptans: triptan responder, triptan-insufficient responder, and triptan naïve. Co-primary efficacy endpoints were pain freedom and absence of most bothersome migraine-associated symptom (MBS) 2 h post initial dose. Adverse events (AEs) within historical triptan experience subgroups were evaluated. RESULTS: In the pooled analysis population (n = 1799), 682 (placebo, n = 350; ubrogepant 50 mg, n = 332), 451 (placebo, n = 223; ubrogepant, n = 228), and 666 (placebo, n = 339; ubrogepant, n = 327) participants were triptan responders, triptan-insufficient responders, and triptan-naïve, respectively. Response rates on co-primary efficacy endpoints were higher for ubrogepant versus placebo across all groups. Treatment-by-subgroup interaction p values based on odds ratios for pain freedom (p = 0.290) and absence of MBS (p = 0.705) indicated no significant impact of historical triptan experience on ubrogepant efficacy. AE incidence for ubrogepant did not differ appreciably across historical triptan experience subgroups. CONCLUSIONS: Ubrogepant efficacy and tolerability did not differ for the acute treatment of migraine in participants classified as triptan responders, triptan-insufficient responders, and triptan-naïve based on their historical experience with triptans.

Mechanistic Investigations Support Liver Safety of Ubrogepant.

Small-molecule calcitonin gene-related peptide (CGRP) receptor antagonists have demonstrated therapeutic efficacy for the treatment of migraine. However, previously investigated CGRP receptor antagonists, telcagepant and MK-3207, were discontinued during clinical development because of concerns about drug-induced liver injury. A subsequent effort to identify novel CGRP receptor antagonists less likely to cause hepatotoxicity led to the development of ubrogepant. The selection of ubrogepant, following a series of mechanistic studies conducted with MK-3207 and telcagepant, was focused on key structural modifications suggesting that ubrogepant was less prone to forming reactive metabolites than previous compounds. The potential for each drug to cause liver toxicity was subsequently assessed using a quantitative systems toxicology approach (DILIsym) that incorporates quantitative assessments of mitochondrial dysfunction, disruption of bile acid homeostasis, and oxidative stress, along with estimates of dose-dependent drug exposure to and within liver cells. DILIsym successfully modeled liver toxicity for telcagepant and MK-3207 at the dosing regimens used in clinical trials. In contrast, DILIsym predicted no hepatotoxicity during treatment with ubrogepant, even at daily doses up to 1000 mg (10-fold higher than the approved clinical dose of 100 mg). These predictions are consistent with clinical trial experience showing that ubrogepant has lower potential to cause hepatotoxicity than has been observed with telcagepant and MK-3207.

Erenumab: A novel calcitonin gene-related peptide receptor antagonist developed specifically for migraine prevention.

Headaches and migraines continue to be a leading cause of suffering and disability. As per the Global Burden of Disease Survey conducted in 2010, the exact magnitude of the disease still is underestimated. Migraine alone continues to rank seventh as a cause of disability. Various therapeutic modalities exist and newer classes of medications are currently being trialed to provide effective treatment to this population of patients. Erenumab, a calcitonin gene-related peptide receptor inhibitor, is a recent addition to this armamentarium and has been approved by the FDA for use in 2018. It has shown modestly improved outcomes according to the current trials. However, long-term outcomes and adverse effects still are under research. The following article elaborates on the current literature and evidence on this novel drug.

A phase IIb randomized, double-blind, placebo-controlled trial of ubrogepant for the acute treatment of migraine.

AIM: The aim of this trial was to evaluate the efficacy and tolerability of ubrogepant (MK-1602), a calcitonin gene-related peptide receptor antagonist (CGRP-RA), for the acute treatment of migraine. METHODS: This double-blind, placebo-controlled study randomized 834 participants to treat one migraine attack with ubrogepant 1 mg, 10 mg, 25 mg, 50 mg, 100 mg, or placebo in a 1:1 ratio. The co-primary endpoints were pain freedom and headache response at two hours. The first primary hypothesis tested the dose-response trend for two-hour pain freedom using a logistic regression model. Subsequent hypotheses tested the effects of each dose on the co-primary endpoints, using a closed sequential testing procedure to control for multiplicity. RESULTS: A total of 527 participants received ubrogepant and 113 received placebo. A positive response trend in the proportion of participants achieving two-hour pain freedom was demonstrated (p < 0.001). Ubrogepant 100 mg was significantly superior to placebo for two-hour pain freedom (25.5% vs 8.9%) but not for two-hour headache response. Per the prespecified multiplicity strategy, this nonsignificant result precluded further formal hypothesis testing, although the 50 mg and 25 mg doses demonstrated nominal significance over placebo for two-hour pain freedom (unadjusted p < 0.05). Overall, adverse events were similar between ubrogepant and placebo. CONCLUSION: This trial supports ubrogepant's efficacy and provides further evidence that CGRP-RAs are viable options for the acute treatment of migraine.

Efficacy, safety, and tolerability of telcagepant in the treatment of acute migraine: a meta-analysis.

Although triptans are widely used for treating acute migraine, they are contraindicated or not effective in a large proportion of patients. Hence, alternative treatments are needed. Calcitonin gene-related peptide receptor antagonists, such as telcagepant, have been under investigation as a treatment for acute migraine. A meta-analysis of the efficacy of telcagepant vs. placebo and triptans (zolmitriptan or rizatriptan) was performed. Randomized controlled trials were indentified from databases using the following search terms: migraine; calcitonin gene-related peptide; calcitonin gene-related peptide receptor antagonists; efficacy; safety, and telcagepant. The primary outcome measure was pain freedom 2 hours after first treatment. The secondary outcome measure was pain relief 2 hours after first treatment. Eight trials were included in the meta-analysis (telcagepant = 4011 participants). The difference in pain freedom at 2 hours significantly favored telcagepant over placebo (odds ratio = 2.70, 95% confidence interval = 2.27-3.21, P < 0.001) and triptans over telcagepant (odds ratio = 0.68, 95% confidence interval = 0.56-0.83, P < 0.001). The difference in pain relief at 2 hours significantly favored telcagepant over placebo (odds ratio = 2.48, 95% confidence interval = 2.18-2.81, P < 0.001). The difference in pain relief at 2 hours did not significantly favor telcagepant over triptans or vice versa (odds ratio = 0.76, 95% confidence interval = 0.57-1.01, P = 0.061). These findings indicate that telcagepant can be effective for treating acute migraine. Calcitonin gene-related peptide receptor antagonists represent a potentially important alternative means of treating acute migraine.