Development of 2-Aminotetralin-Type Serotonin 5-HT1 Agonists: Molecular Determinants for Selective Binding and Signaling at 5-HT1A, 5-HT1B, 5-HT1D, and 5-HT1F Receptors.

The serotonin (5-hydroxytryptamine, 5-HT) 5-HT1 G-protein coupled receptor subtypes (5-HT1A/1B/1D/1E/1F) share a high sequence homology, confounding development of subtype-specific ligands. This study used a 5-HT1 structure-based ligand design approach to develop subtype-selective ligands using a 5-substituted-2-aminotetralin (5-SAT) chemotype, leveraging results from pharmacological, molecular modeling, and mutagenesis studies to delineate molecular determinants for 5-SAT binding and function at 5-HT1 subtypes. 5-SATs demonstrated high affinity (Ki ≤ 25 nM) and at least 50-fold stereoselective preference ([2S] > [2R]) at 5-HT1A, 5-HT1B, and 5-HT1D receptors but essentially nil affinity (Ki > 1 µM) at 5-HT1F receptors. The 5-SATs tested were agonists with varying degrees of potency and efficacy, depending on chemotype substitution and 5-HT1 receptor subtype. Models were built from the 5-HT1A (cryo-EM), 5-HT1B (crystal), and 5-HT1D (cryo-EM) structures, and 5-SATs underwent docking studies with up to 1 µs molecular dynamics simulations. 5-SAT interactions observed at positions 3.33, 5.38, 5.42, 5.43, and 7.39 of 5-HT1 subtypes were confirmed with point mutation experiments. Additional 5-SATs were designed and synthesized to exploit experimental and computational results, yielding a new full efficacy 5-HT1A agonist with 100-fold selectivity over 5-HT1B/1D receptors. The results presented lay the foundation for the development of additional 5-HT1 subtype selective ligands for drug discovery purposes.

The 5-HT1F receptor as the target of ditans in migraine - from bench to bedside.

Migraine is a leading cause of disability in more than one billion people worldwide, yet it remains universally underappreciated, even by individuals with the condition. Among other shortcomings, current treatments (often repurposed agents) have limited efficacy and potential adverse effects, leading to low treatment adherence. After the introduction of agents that target the calcitonin gene-related peptide pathway, another new drug class, the ditans - a group of selective serotonin 5-HT1F receptor agonists - has just reached the international market. Here, we review preclinical studies from the late 1990s and more recent clinical research that contributed to the development of the ditans and led to their approval for acute migraine treatment by the US Food and Drug Administration and the European Medicines Agency.

The role of hippocampal 5-HT1D and 5-HT1F receptors on learning and memory in rats.

Serotonin is a neurotransmitter, which is involved in memory via its receptors. The 5-HT1D and 5-HT1F receptors mainly exist in the hippocampus, which plays an important role in memory processing. However, few studies have assessed the effect of these serotonin receptors on memory. We evaluated the effect of a 5-HT1D receptor agonist, PNU142633, 5-HT1D receptor antagonist, BRL15572 hydrochloride, and 5-HT1F receptor agonist, LY344864, on the recognition and avoidance memory in the hippocampus area. Fifty adult male Wistar rats weighing 200-250 g were divided into the control, sham-operated, PNU, BRL, and LY groups (n=10 per group). Bilateral guide cannulas were implanted into the dentate gyrus area of the hippocampus. The drugs were administered at the dose of 1 µg/µl before the novel object recognition (NOR) and passive avoidance learning (PAL) tests. The results showed that in the NOR test, the administration of PNU and LY had no significant effect on recognition index; however, the recognition index was increased by BRL. In the PAL test, the administration of PNU had no significant effect on recognition index, but the administration of BRL and LY increased the time spent in the dark compartment of the apparatus and decreased the step-through latency into the dark compartment apparatus. It can be concluded that the inhibition of the hippocampal 5-HT1D receptor improved cognition memory but impaired avoidance memory. Activation of the hippocampal 5-HT1F receptor had no effect on cognitive memory but impaired avoidance memory.

Changes in 5-HT1F receptor expression in rats with spasticity following spinal cord injury.

Spasticity is a common complication in patients with spinal cord injury (SCI) and adversely affects patients' quality of life. Little is known about the distribution of the serotonin 1F receptor (5-HT1FR) in the spinal cord, especially in relation to the spasticity caused by SCI. Adult male Wistar rats were divided into a sham-operation group and spinalized group. SCI-induced spasticity was caused by spinal transection at the second sacral segment. The spinal cord below the transection was obtained at the end of the experiment. The expression and distribution of 5-HT1FR in the spinal cord were analyzed. The results showed that the expression of 5-HT1FR (mRNA and protein) exhibited the same downward trend after spinal transection and reached the lowest expression level at 2 and 5 days, respectively. The expression of 5-HT1FR (mRNA and protein) thereafter gradually approached the levels in the sham-operation group after 60 days. Immunostaining suggested that 5-HT1FR showed particularly strong expression in the ventral horn (VH) region. The time course of 5-HT1FR mRNA downregulation is positively correlated with the development of tail spasticity after sacral spinal cord transection. There may be a connection between 5-HT1FR and the occurrence of spasticity, but elucidation of the specific mechanism needs further experimental verification.

The selective 5-HT1F receptor agonist lasmiditan inhibits trigeminal nociceptive processing: Implications for migraine and cluster headache.

BACKGROUND AND PURPOSE: Lasmiditan is a novel selective 5-HT1F receptor agonist, recently approved for acute treatment of migraine. 5-HT1F receptors are widely expressed in the CNS and trigeminovascular system. Here, we have explored the therapeutic effects of 5-HT1F receptor activation in preclinical models of migraine and cluster headache. EXPERIMENTAL APPROACH: Electrical stimulation of the dura mater or the superior salivatory nucleus in anaesthetised rats evoked trigeminovascular or trigeminal-autonomic reflex activation at the level of the trigeminocervical complex. Additionally, cranial autonomic manifestations in response to trigeminal-autonomic reflex activation were measured, via anterior choroidal blood flow alterations. These responses were then challenged with lasmiditan. We explored the tissue distribution of mRNA for 5-HT1F receptors in human post-mortem tissue and of several 5-HT1 receptor subtypes in specific tissue beds. KEY RESULTS: Lasmiditan dose-dependently reduced trigeminovascular activation in a preclinical model of migraine. Lasmiditan also reduced superior salivatory nucleus-evoked activation of the trigeminal-autonomic reflex, but had no effect on cranial autonomic activation. mRNA profiling in human tissue showed expression of the 5-HT1F receptor in several structures relevant for migraine and cluster headache. CONCLUSION AND IMPLICATIONS: Our data suggest that lasmiditan acts, at least in part, as an anti-migraine agent by reducing trigeminovascular activation. Furthermore, our results highlight a clear action for lasmiditan in a preclinical model of cluster headache. Given the proven translational efficacy of this model, our data support the potential utility of lasmiditan as a therapeutic option for the acute treatment of cluster headache attacks. LINKED ARTICLES: This article is part of a themed issue on Advances in Migraine and Headache Therapy (BJP 75th Anniversary). To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v179.3/issuetoc.

The Effect and Safety of 5-HT1F Receptor Agonist Lasmiditan on Migraine: A Systematic Review and Meta-Analysis.

BACKGROUND: Migraine has a great impact on public health. Current acute therapies do not satisfy all migraineurs. The novel serotonin 5-HT1F receptor agonist appears more promising for aborting migraine attacks. OBJECTIVE: To evaluate the clinical efficacy and safety of lasmiditan in treating acute migraine attacks. METHODS: The literature search was performed in PubMed, Embase, and the Cochrane Central Register of Controlled Trials for randomized controlled trials (RCTs) which assessed the effect and safety of lasmiditan on migraine. The risk of bias was assessed using the Cochrane Collaboration's risk of bias tool. Results were extracted and pooled as risk ratios (RRs) with a fixed or random-effects model. RESULTS: Based on the four included RCTs, pooled estimates showed that lasmiditan with the 50 mg, 100 mg, and 200 mg doses was superior to placebo at 2 h after the first dose in terms of pain freedom, absence of migraine-associated symptoms, headache relief, no/mild disability, and global impression of change (very much/much better) (RRs ranged from 1.13 to 1.96), except for nausea-free and vomiting-free. Both lasmiditan 100 mg and 200 mg resulted in significantly fewer patients using rescue medication (100 mg: RR = 0.75, 95% CI (0.61, 0.92), P = 0.007; 200 mg: RR = 0.81, 95% CI (0.66, 0.99), P = 0.04) at 2-24 h postdose, compared with placebo. Safety data showed that the proportion of patients reporting at least one treatment-emergent adverse event (TEAE) and the incidence of most common TEAEs such as dizziness, paresthesia, fatigue, somnolence, and nausea was higher in the lasmiditan groups (50 mg, 100 mg, and 200 mg), compared with placebo. There was no significant difference between lasmiditan and placebo in terms of cardiovascular-related TEAEs (RR = 2.75, 95% CI (0.81, 9.37), P = 0.11). Compared with lasmiditan 100 mg, lasmiditan 200 mg was more effective in pain freedom at 2 h after the first dose (RR = 0.83, 95% CI (0.74, 0.94), P = 0.004) but associated with a higher risk of reporting at least one TEAE (RR = 0.88, 95% CI (0.81, 0.96), P = 0.006). CONCLUSIONS: Lasmiditan with the 50 mg, 100 mg, and 200 mg doses are effective and safe in acute migraine treatment. Lasmiditan 200 mg is more effective than lasmiditan 100 mg in pain freedom, while lasmiditan 100 mg is better tolerated in the short-term follow-up. Further larger sample-size RCTs are required to verify the applicability and tolerability in the long term.

Design, synthesis and biological evaluation of pyridinylmethylenepiperidine derivatives as potent 5-HT1F receptor agonists for migraine therapy.

Migraine is a common neurovascular disease which has been classified as the sixth most disabling disorder. Current migraine therapy was triptans, however, riptans can cause contraction of blood vessels. Therefore, novel drugs without cardiovascular effects emerged, such as CGRP and selective 5-HT1F receptor agonists. In this work, a series of pyridinylmethylenepiperidine derivatives were designed, synthesized and evaluated for their 5-HT1F receptor agonist activity. The results in vitro showed that compound C1-C6 displayed potent agonist activities compared with positive drug lasmiditan. Pharmacokinetic properties in rat indicated that 2,4,6-trifluoro-N-(6-(fluoro(1-methylpiperidin-4-ylidene)methyl)pyridin-2-yl)benzamide (C5) possessed high AUC and good bioavailability. In two rodent models of migraine, C5 significantly inhibited dural plasma protein extravasation and c-fos expression in the trigeminal nucleus caudalis. Moreover, C5 showed no effect on vasoconstriction. Through these studies, we identified C5 as a potent 5-HT1F receptor agonist for migraine therapy.

The American Headache Society Consensus Statement: Update on integrating new migraine treatments into clinical practice.

OBJECTIVE: To incorporate recent research findings, expert consensus, and patient perspectives into updated guidance on the use of new acute and preventive treatments for migraine in adults. BACKGROUND: The American Headache Society previously published a Consensus Statement on the use of newly introduced treatments for adults with migraine. This update, which is based on the expanded evidence base and emerging expert consensus concerning postapproval usage, provides practical recommendations in the absence of a formal guideline. METHODS: This update involved four steps: (1) review of data about the efficacy, safety, and clinical use of migraine treatments introduced since the previous Statement was published; (2) incorporation of these data into a proposed update; (3) review and commentary by the Board of Directors of the American Headache Society and patients and advocates associated with the American Migraine Foundation; (4) consideration of these collective insights and integration into an updated Consensus Statement. RESULTS: Since the last Consensus Statement, no evidence has emerged to alter the established principles of either acute or preventive treatment. Newly introduced acute treatments include two small-molecule calcitonin gene-related peptide (CGRP) receptor antagonists (ubrogepant, rimegepant); a serotonin (5-HT1F ) agonist (lasmiditan); a nonsteroidal anti-inflammatory drug (celecoxib oral solution); and a neuromodulatory device (remote electrical neuromodulation). New preventive treatments include an intravenous anti-CGRP ligand monoclonal antibody (eptinezumab). Several modalities, including neuromodulation (electrical trigeminal nerve stimulation, noninvasive vagus nerve stimulation, single-pulse transcranial magnetic stimulation) and biobehavioral therapy (cognitive behavioral therapy, biofeedback, relaxation therapies, mindfulness-based therapies, acceptance and commitment therapy) may be appropriate for either acute and/or preventive treatment; a neuromodulation device may be appropriate for acute migraine treatment only (remote electrical neuromodulation). CONCLUSIONS: The integration of new treatments into clinical practice should be informed by the potential for benefit relative to established therapies, as well as by the characteristics and preferences of individual patients.

Novel Therapies in Acute Migraine Management: Small-Molecule Calcitonin Gene-Receptor Antagonists and Serotonin 1F Receptor Agonist.

OBJECTIVE: To review the efficacy, safety, and cost of 3 newly approved agents-ubrogepant, lasmiditan, and rimegepant-representing 2 therapeutic classes, calcitonin gene-related peptide (CGRP) receptor antagonist and serotonin 1F (5-HT1F) agonists, for the acute treatment of migraine with or without aura. DATA SOURCES: The Institute of Health US National Library of Medicine Clinical Trials, PubMed, and Cochrane databases were queried. Abstracts, journal articles, and other relevant sources published or present were reviewed. Search terms included the following: ubrogepant, MK-1602, Ubrelvy®, rimegepant, Nurtec®, BHV-3000, BMS-927711, lasmiditan, Reyvow®, LY573144. STUDY SELECTION AND DATA EXTRACTION: Relevant English-language articles from June 30, 2010, to August 31, 2020, were evaluated and included in the narrative. DATA SYNTHESIS: CGRP receptor antagonists, ubrogepant and rimegepant, achieved 2-hour pain freedom and freedom from the most bothersome migraine symptom (MBS) at 2 hours. Both agents were well tolerated, with adverse effects similar to placebo. Lasmiditan, a 5-HT1F receptor antagonist, also improved 2-hour pain freedom and freedom from the MBS at 2 hours. Lasmiditan is associated with dizziness, paresthesia, somnolence, nausea, fatigue, and lethargy. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: Ubrogepant, rimegepant, and lasmiditan represent a new and exciting chapter in acute migraine therapy. To date, no head-to-head studies have compared these agents with the triptans. Ubrogepant and lasmiditan are effective in triptan nonresponders. None of the 3 agents is contraindicated in cardiovascular disease, unlike the triptans. CONCLUSIONS: Based on available data, ubrogepant, rimegepant, and lasmiditan should be reserved as second-line therapy and may be safe in patients with cardiovascular risk. Lasmiditan's adverse effect profile may limit its use.

The effectiveness and value of novel acute treatments for migraine.

DISCLOSURES: Funding for this summary was contributed by Arnold Ventures, California Health Care Foundation, Harvard Pilgrim Health Care, and Kaiser Foundation Health Plan to the Institute for Clinical and Economic Review (ICER), an independent organization that evaluates the evidence on the value of health care interventions. ICER's annual policy summit is supported by dues from Aetna, America's Health Insurance Plans, Anthem, Allergan, Alnylam, AstraZeneca, Biogen, Blue Shield of CA, Boehringer-Ingelheim, Cambia Health Services, CVS, Editas, Express Scripts, Genentech/Roche, GlaxoSmithKline, Harvard Pilgrim, Health Care Service Corporation, HealthFirst, Health Partners, Johnson & Johnson (Janssen), Kaiser Permanente, LEO Pharma, Mallinckrodt, Merck, Novartis, National Pharmaceutical Council, Pfizer, Premera, Prime Therapeutics, Regeneron, Sanofi, Spark Therapeutics, and United Healthcare. Agboola, Borrelli, Rind, and Pearson are employed by ICER. Touchette, through the University of Illinois at Chicago, received funding from ICER for development of the economic model described in this publication. Atlas has nothing to disclose.

Targeting the 5-HT1B/1D and 5-HT1F receptors for acute migraine treatment.

Migraine is a common and highly disabling headache disorder associated with a substantial socioeconomic burden. Migraine treatments can be categorized as preventive treatment, aimed at reducing the frequency and severity of migraine attacks, and acute therapy, intended to abort attacks. Traditionally, acute treatment can be classified as specific (ergot derivatives and triptans) or nonspecific (analgesics and nonsteroidal anti-inflammatory drugs). Triptans, a class of 5-HT1B/1D receptor agonists with some affinity for the 5-HT1F receptor subtype, have been proven to be efficacious for acute treatment of moderate to severe migraine and have been deemed the gold standard. The availability of triptans in non-oral formulations, such as subcutaneous (SC) and intranasal forms, can be beneficial for patients who suffer from prominent nausea or vomiting, have a suboptimal response to oral agents, and/or seek a more rapid onset of treatment effects. However, triptans are contraindicated in patients with preexisting cardiovascular and/or cerebrovascular diseases due to their 5-HT1B-mediated vasoconstrictive action. For this reason, studies have focused on the development of ditans, a group of antimigraine drugs targeting 5-HT1D and 5-HT1F receptors. Unfortunately, 5-HT1D receptor agonists have been shown to be ineffective in the acute treatment of migraine. Several ditans targeting the 5-HT1F receptor have been developed and have shown no vasoconstrictive effect in preclinical studies, but only two of them, lasmiditan and LY334370, have been tested in clinical trials for migraine, and only lasmiditan has reached to Phase III clinical trials. These Phase III trials have demonstrated the efficacy and safety of lasmiditan, a selective 5-HT1F receptor agonist, in acute migraine treatment. Lasmiditan might offer an alternative migraine therapy without cardiovascular risks. This review will summarize the development of agents targeting the 5-HT1B/1D and 5-HT1F receptors and the clinical evidence supporting the use of these agents for acute migraine treatment.

Differential medication overuse risk of novel anti-migraine therapeutics.

Medication overuse headache is estimated to affect 2% of the population, and is ranked in the top 20 most disabling disorders due to its high level of disability. Several therapies used in the treatment of acute migraine are thought to be associated with medication overuse headache, including opioids and triptans. With limited treatment options, it is critical to determine the risk profile of novel therapies prior to their widespread use. The current study explores the potential medication overuse risk of two novel therapeutic drug classes, namely the ditans: 5-HT1F receptor agonists, and the gepants: calcitonin gene-related peptide receptor antagonists, in a preclinical model of medication overuse. Persistent exposure of mice to the 5-HT1F agonist LY344864, but not olcegepant produced a significant reduction in hind paw and orofacial mechanical withdrawal thresholds as a surrogate readout of allodynia. In agreement, only LY344864 induced neuroplastic changes in trigeminal sensory afferents, increasing calcitonin gene-related peptide expression and basal trigeminal nociception. Our data highlight a differential medication overuse headache risk profile for the ditan and gepant classes of drugs that has important implications for their clinical use and patient education to help reduce the burden of medication overuse headache.

Evaluation of 2-Hour Post-Dose Efficacy of Lasmiditan for the Acute Treatment of Difficult-to-Treat Migraine Attacks.

OBJECTIVE: To identify factors predicting response (2-hour headache pain freedom or most bothersome symptom freedom) to lasmiditan based on individual patient characteristics, migraine disease characteristics, and migraine attack characteristics. Further, efficacy specifically in difficult-to-treat patient/migraine disease characteristics or attack characteristics (ie, historically considered less responsive to certain acute therapies) subgroups was analyzed. BACKGROUND: Knowledge of factors associated with a positive or negative response to acute treatment would be useful to practitioners prescribing acute treatments for migraine. Additionally, practitioners and patients would benefit from understanding the efficacy of lasmiditan specifically in subgroups of patients with migraine disease characteristics and migraine attack characteristics historically associated with decreased pain threshold, reduced efficacy of acute treatment, or increased burden of migraine. METHODS: Pooled analyses were completed from 2 Phase 3 double-blind clinical trials, SPARTAN and SAMURAI. Data from baseline to 2 hours after taking lasmiditan (50, 100, or 200 mg) or placebo were analyzed to assess efficacy based on patient characteristics, migraine disease characteristics, and migraine attack characteristics. A total of 3981 patients comprising the intent-to-treat population were treated with placebo (N = 1130), lasmiditan 50 mg (N = 598), lasmiditan 100 mg (N = 1133), or lasmiditan 200 mg (N = 1120). Data were analyzed for the following efficacy measures at 2 hours: headache pain freedom and most bothersome symptom freedom. RESULTS: None of the analyzed subgroups based on individual patient characteristics, migraine disease characteristics, or migraine attack characteristics predicted headache pain freedom or most bothersome symptom freedom response at 2 hours following lasmiditan treatment (interaction P ≥ .1). For the difficult-to-treat patient/migraine disease characteristics subgroups (defined as those with ≥24 headache days in the past 3 months, duration of migraine history ≥20 years, severe disability [Migraine Disability Assessment score ≥21], obesity [≥30 kg/m2 ], and history of psychiatric disorder), single doses of lasmiditan (100 or 200 mg) were significantly more effective than placebo (P ≤ .002) in achieving both endpoints. Headache pain freedom response rates for higher doses of lasmiditan were numerically greater than for lower doses of lasmiditan. For the difficult-to-treat migraine attack subgroups, patients with severe headache, co-existent nausea at the time of treatment, or who delayed treatment for ≥2 hours from the time of headache onset, both endpoint response rates after lasmiditan 100 or 200 mg were significantly greater than after placebo. Among those who delayed treatment for ≥4 hours from the time of headache onset, headache pain freedom response rates for the 200 mg dose of lasmiditan met statistical significance vs placebo (32.4% vs 15.9%; odds ratio = 2.7 [1.17, 6.07]; P = .018). While the predictors of response interaction test showed similar efficacy of lasmiditan vs placebo across subgroups defined by baseline functional disability (mild, moderate, or needs complete bed rest) at the time of treatment, analyses of lasmiditan efficacy within the subgroup "needs complete bed rest" appeared to show less efficacy (eg, in the 200 mg vs placebo group, 25.9% vs 18.5%; odds ratio = 1.56 [0.96, 2.53]; P = .070). CONCLUSIONS: Efficacy of lasmiditan 200 and 100 mg for headache pain freedom and most bothersome symptom freedom at 2 hours post-treatment was generally not influenced by the individual patient characteristics, migraine disease history, or migraine attack characteristics that were analyzed. In the analyses of difficult-to-treat subgroups, patients receiving lasmiditan achieved greater responses (2-hour headache pain freedom and most bothersome symptom freedom) vs placebo recipients.

Short-term efficacy and safety of lasmiditan, a novel 5-HT1F receptor agonist, for the acute treatment of migraine: a systematic review and meta-analysis.

BACKGROUND: Migraine has been recognized as one of common diseases in the world whose current treatment options are not ideal. Lasmiditan, an oral 5-hydroxytryptamine (HT)1F receptor agonist, appears more promising for the acute treatment of migraine because of considerably better effect profiles with no severe adverse events (AEs). This review aimed to systematically evaluate the efficacy and safety of lasmiditan from the results of randomized controlled trials (RCTs). METHODS: PubMed, Cochrane Library, Embase were searched on lasmiditan for the acute treatment of migraine from inception of the databases to Feb 1, 2020. Pain free and pain relief, global impression (very much/much better), and no/mild disability at 2 h in efficacy; total treatment-emergent adverse events (TEAEs), dizziness, nausea, fatigue, paraesthesia and somnolence in safety were extracted from the included studies. A systematic review and meta-analysis was performed using Review Manager Software version 5.3 (RevMan 5.3). RESULTS: Four RCTs with a total of 4960 subjects met our inclusion criteria. The overall effect estimate showed that lasmiditan was significantly superior to placebo in terms of pain free (RR 1.71, 95% CI 1.55-1.87), pain relief (RR 1.40, 95% CI 1.33-1.47), global impression (very much/much better) (RR 1.55, 95% CI 1.44-1.67), and no/mild disability (RR 1.15, 95% CI 1.10-1.20) at 2 h. For the safety, significant number of patients experienced TEAEs with lasmiditan than with placebo (RR 2.77, 95% CI 2.53-3.03), most TEAEs were central nervous system (CNS)-related and included dizziness (RR 5.81, 95% CI 4.72-7.14), nausea (RR 2.58, 95% CI 1.87-3.57), fatigue (RR 5.38, 95% CI 3.78-7.66), paraesthesia (RR 4.48, 95% CI 3.33-6.02), and somnolence (RR 2.82, 95% CI 2.18-3.66). CONCLUSIONS: This meta-analysis suggests that lasmiditan is effective for the acute treatment of migraine with a higher incidence of CNS-related adverse reactions compared with placebo. Long-term, open-label, multi-dose trials are required to verify the current findings.

Lasmiditan mechanism of action - review of a selective 5-HT1F agonist.

Migraine is a leading cause of disability worldwide, but it is still underdiagnosed and undertreated. Research on the pathophysiology of this neurological disease led to the discovery that calcitonin gene-related peptide (CGRP) is a key neuropeptide involved in pain signaling during a migraine attack. CGRP-mediated neuronal sensitization and glutamate-based second- and third-order neuronal signaling may be an important component involved in migraine pain. The activation of several serotonergic receptor subtypes can block the release of CGRP, other neuropeptides, and neurotransmitters, and can relieve the symptoms of migraine. Triptans were the first therapeutics developed for the treatment of migraine, working through serotonin 5-HT1B/1D receptors. The discovery that the serotonin 1F (5-HT1F) receptor was expressed in the human trigeminal ganglion suggested that this receptor subtype may have a role in the treatment of migraine. The 5-HT1F receptor is found on terminals and cell bodies of trigeminal ganglion neurons and can modulate the release of CGRP from these nerves. Unlike 5-HT1B receptors, the activation of 5-HT1F receptors does not cause vasoconstriction.The potency of different serotonergic agonists towards 5-HT1F was correlated in an animal model of migraine (dural plasma protein extravasation model) leading to the development of lasmiditan. Lasmiditan is a newly approved acute treatment for migraine in the United States and is a lipophilic, highly selective 5-HT1F agonist that can cross the blood-brain barrier and act at peripheral nervous system (PNS) and central nervous system (CNS) sites.Lasmiditan activation of CNS-located 5-HT1F receptors (e.g., in the trigeminal nucleus caudalis) could potentially block the release of CGRP and the neurotransmitter glutamate, thus preventing and possibly reversing the development of central sensitization. Activation of 5-HT1F receptors in the thalamus can block secondary central sensitization of this region, which is associated with progression of migraine and extracephalic cutaneous allodynia. The 5-HT1F receptors are also elements of descending pain modulation, presenting another site where lasmiditan may alleviate migraine. There is emerging evidence that mitochondrial dysfunction might be implicated in the pathophysiology of migraine, and that 5-HT1F receptors can promote mitochondrial biogenesis. While the exact mechanism is unknown, evidence suggests that lasmiditan can alleviate migraine through 5-HT1F agonist activity that leads to inhibition of neuropeptide and neurotransmitter release and inhibition of PNS trigeminovascular and CNS pain signaling pathways.

Effects of lasmiditan on simulated driving performance: Results of two randomized, blinded, crossover studies with placebo and active controls.

OBJECTIVE: To evaluate the impact of lasmiditan, an oral, centrally-penetrant, selective serotonin 1F (5-HT1F ) receptor agonist developed for the acute treatment of migraine, on simulated driving. METHODS: Healthy adult volunteers enrolled in two randomized, placebo and active comparator-controlled, crossover studies. Study 1 (N = 90) tested lasmiditan (50-, 100-, 200-mg), alprazolam (1-mg), and placebo at 1.5 hr post-dose. Study 2 (N = 68) tested lasmiditan (100-, 200-mg), diphenhydramine (50-mg, administered 2 hr pre-assessments), and placebo at 8, 12 and 24 hr post-dose. Driving performance was assessed using a validated driving simulator employing a 100 km driving scenario. Standard deviation of lateral position (SDLP), a measure of lane position control, was the primary endpoint. RESULTS: Assay sensitivity was confirmed by increased SDLP for active comparators at 1.5- and 8-hr time points. Lasmiditan doses showed significant driving impairment versus placebo at 1.5 hr post-dose. Lasmiditan doses were non-inferior to placebo at 8 hr. Driving impairment was concentration-dependent at 1.5 hr but not at 8 hr. Common adverse events were central nervous system-related and mild-to-moderate in severity. CONCLUSIONS: Lasmiditan was associated with impaired simulated driving performance at 1.5 hr post-dose, but showed no clinically meaningful impairment at 8 hr post-dose.

Pharmacological treatment of migraine: CGRP and 5-HT beyond the triptans.

Migraine is a highly disabling neurovascular disorder characterized by a severe headache (associated with nausea, photophobia and/or phonophobia), and trigeminovascular system activation involving the release of calcitonin-gene related peptide (CGRP). Novel anti-migraine drugs target CGRP signaling through either stimulation of 5-HT1F receptors on trigeminovascular nerves (resulting in inhibition of CGRP release) or direct blockade of CGRP or its receptor. Lasmiditan is a highly selective 5-HT1F receptor agonist and, unlike the triptans, is devoid of vasoconstrictive properties, allowing its use in patients with cardiovascular risk. Since lasmiditan can actively penetrate the blood-brain barrier, central therapeutic as well as side effects mediated by 5-HT1F receptor activation should be further investigated. Other novel anti-migraine drugs target CGRP signaling directly. This neuropeptide can be targeted by the monoclonal antibodies eptinezumab, fremanezumab and galcanezumab, or by CGRP-neutralizing L-aptamers called Spiegelmers. The CGRP receptor can be targeted by the monoclonal antibody erenumab, or by small-molecule antagonists called gepants. Currently, rimegepant and ubrogepant have been developed for acute migraine treatment, while atogepant is studied for migraine prophylaxis. Of these drugs targeting CGRP signaling directly, eptinezumab, erenumab, fremanezumab, galcanezumab, rimegepant and ubrogepant have been approved for clinical use, while atogepant is in the last stage before approval. Although all of these drugs seem highly promising for migraine treatment, their safety should be investigated in the long-term. Moreover, the exact mechanism(s) of action of these drugs need to be elucidated further, to increase both safety and efficacy and to increase the number of responders to the different treatments, so that all migraine patients can satisfactorily be treated.

Effects of new generation triptans - frovatriptan and almotriptan - on hemodynamic parameters in intact male and female rats.

The introduction of the second generation triptans in clinical and experimental practice was a major progress in the pharmacotherapy of migraine. Frovatriptan is a second generation triptan with strong 5-HT1B/1D serotonergic agonism and low 5-HT1A/7 receptor affinity, while almotriptan possesses not only the typical 5-HT1B/1D receptor agonist activity, but shows an affinity to the 5-HT1F receptor. The aim of our study was to assess the impact of frovatriptan and almotriptan on hemodynamics in male and female rats. We used a non-invasive "tail-cuff" method to measure the arterial blood pressure. Female and male Wistar rats were treated separately with high and low dosages of frovatriptan and almotriptan. Male and female rats showed reduction in all hemodynamic parameters, but only male rats showed an increase in the heart rate. In general, we could say that both almotriptan and frovatriptan potentiate cardiovascular safety.

Profiling lasmiditan as a treatment option for migraine.

Introduction: In recent years, research into acute migraine treatment has aimed to develop molecules capable of inhibiting trigeminal pathways, mediated by agonism to 5-HT1F receptors in order to avoid the vasoconstrictive action due to the stimulation of 5-HT 1B/1D receptors. A novel migraine drug class, called 'neurally acting anti-migraine agents', has been developed for the management of acute migraine attacks. Lasmiditan is the only compound of this drug class that has been evaluated in Phase III clinical trials.Areas covered: This review discusses lasmiditan including its pharmacokinetics, pharmacodynamics, efficacy and safety profile. Original research and review articles, relative to the period 2010-2019, were included in the reviewed literature.Expert opinion: The most recent phase III trials have demonstrated the efficacy of lasmiditan for acute migraine treatment, even if compared only with placebo. Nevertheless, the low rate of cardiovascular side effects with lasmiditan might offer a potential therapeutic option for migraine patients with cardiovascular disorders. With the lack of data on lasmiditan's pharmacokinetic features, several phase I clinical trials are still ongoing in order to evaluate half-life, metabolism, excretion and the potential production of active metabolites. Possible pharmacodynamic interaction with drugs acting on central nervous system should be evaluated in future studies.

5-hydroxytryptamine 1F Receptor Agonist Induces Mitochondrial Biogenesis and Promotes Recovery from Spinal Cord Injury.

Spinal cord injury (SCI) is characterized by vascular disruption leading to ischemia, decreased oxygen delivery, and loss of mitochondrial homeostasis. This mitochondrial dysfunction results in loss of cellular functions, calcium overload, and oxidative stress. Pharmacological induction of mitochondrial biogenesis (MB) may be an effective approach to treat SCI. LY344864, a 5-hydroxytryptamine 1F (5-HT1F) receptor agonist, is a potent inducer of MB in multiple organ systems. To assess the efficacy of LY344864-induced MB on recovery post-SCI, female mice were subjected to moderate force-controlled impactor-induced contusion SCI followed by daily LY344864 administration for 21 days. Decreased mitochondrial DNA and protein content was present in the injury site 3 days post-SCI. LY344864 treatment beginning 1 h after injury attenuated these decreases, indicating MB. Additionally, injured mice treated with LY344864 displayed decreased Evan's Blue dye accumulation in the spinal cord compared with vehicle-treated mice 7 days after injury, suggesting restoration of vascular integrity. LY344864 also increased locomotor capability, with treated mice reaching a Basso-Mouse Scale score of 3.4 by 21 days, whereas vehicle-treated mice exhibited a score of 1.9. Importantly, knockout of the 5-HT1F receptor blocked LY344864-induced recovery. Remarkably, a similar degree of locomotor restoration was observed when treatment initiation was delayed until 8 h after injury. Furthermore, cross-sectional analysis of the spinal cord 21 days after injury revealed decreased lesion volume with delayed LY344864 treatment initiation, emphasizing the potential clinical applicability of this therapeutic approach. These data provide evidence that induction of MB via 5-HT1F receptor agonism may be a promising strategy for the treatment of SCI. SIGNIFICANCE STATEMENT: Treatment with LY344864 induces mitochondrial biogenesis in both the naive and injured mouse spinal cord. In addition, treatment with LY344864 beginning after impactor-induced contusion spinal cord injury improves mitochondrial homeostasis, blood-spinal cord barrier integrity, and locomotor function within 7 days. Importantly, similar locomotor results are observed whether treatment is initiated at 1 h after injury or 8 h after injury. These data indicate the potential for pharmacological induction of mitochondrial biogenesis through a 5-hydroxytryptamine 1F agonist as a novel therapeutic approach for spinal cord injury.