Calcitonin Gene‐Related Peptide Antagonists in the Treatment of Episodic Migraine

The human NTG model of migraine in drug discovery and development

INTRODUCTION

Various triggers can originate a migraine attack. In healthy volunteers and patients with migraine, the nitroglycerin (NTG) provocation model induces a headache that resembles migraine in pain characteristics and vascular manifestations. This headache is reversible and treatable in monitored conditions, providing an opportunity to test novel antimigraine medications in early clinical development.

AREAS COVERED

This perspective covers the main characteristics and applications of the human NTG model of migraine with effective and ineffective antimigraine therapies.

EXPERT OPINION

The NTG model represents a potential de-risking strategy to test novel hypotheses for antimigraine mechanisms in humans. Considering previous studies conducted with effective and ineffective antimigraine therapies, the sensitivity of the model was 71% while the specificity was 100%. The probability that following an analgesic effect, that compound would truly be efficacious in individuals with migraine was 100%. Following a negative result, the probability that such compound would truly be ineffective in patients with individuals was 33%. A clinical trial testing the analgesic properties of novel compounds after a sublingual and/or intravenous NTG challenge in migraine patients may support a subsequent phase 2 trial for the treatment of migraine.

Not your usual drug-drug interactions: Monoclonal antibody-based therapeutics may interact with antiseizure medications

Therapeutic monoclonal antibodies (mAbs) have emerged as the fastest growing drug class. As such, mAbs are increasingly being co-prescribed with other drugs, including antiseizure medications (ASMs). Although mAbs do not share direct targets or mechanisms of disposition with small-molecule drugs (SMDs), combining therapeutics of both types can increase the risk of adverse effects and treatment failure. The primary goal of this literature review was identifying mAb-ASM combinations requiring the attention of professionals who are treating patients with epilepsy. Systematic PubMed and Embase searches (1980-2021) were performed for terms relating to mAbs, ASMs, drug interactions, and their combinations. Additional information was obtained from documents from the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA). Evidence was critically appraised - key issues calling for clinicians' consideration and important knowledge gaps were identified, and practice recommendations were developed by a group of pharmacists and epileptologists. The majority of interactions were attributed to the indirect effects of cytokine-modulating antibodies on drug metabolism. Conversely, strong inhibitors or inducers of drug-metabolizing enzymes or drug transporters could potentially interact with the cytotoxic payload of antibody-drug conjugates, and ASMs could alter mAb biodistribution. In addition, mAbs could potentiate adverse ASM effects. Unfortunately, few studies involved ASMs, requiring the formulation of class-based recommendations. Based on the current literature, most mAb-ASM interactions do not warrant special precautions. However, specific combinations should preferably be avoided, whereas others require monitoring and potentially adjustment of the ASM doses. Reduced drug efficacy or adverse effects could manifest days to weeks after mAb treatment onset or discontinuation, complicating the implication of drug interactions in potentially deleterious outcomes. Prescribers who treat patients with epilepsy should be familiar with mAb pharmacology to better anticipate potential mAb-ASM interactions and avoid toxicity, loss of seizure control, or impaired efficacy of mAb treatment.

Procalcitonin Exerts a Mediator Role in Septic Shock Through the Calcitonin Gene-Related Peptide Receptor

OBJECTIVES

Clinically, procalcitonin represents the most widely used biomarker of sepsis worldwide with unclear pathophysiologic significance to date. Pharmacologically, procalcitonin was shown to signal through both calcitonin receptor and calcitonin gene-related peptide receptor in vitro, yet the identity of its biologically relevant receptor remains unknown.

DESIGN

Prospective randomized animal investigations and in vitro human blood studies.

SETTING

Research laboratory of a university hospital.

SUBJECTS

C57BL/6J mice and patients with post-traumatic sepsis.

INTERVENTIONS

Procalcitonin-deficient mice were used to decipher a potential mediator role in experimental septic shock and identify the relevant receptor for procalcitonin. Cecal ligation and puncture and endotoxemia models were employed to investigate septic shock. Disease progression was evaluated through survival analysis, histology, proteome profiling, gene expression, and flow cytometry. Mechanistic studies were performed with cultured macrophages, dendritic cells, and gamma delta T cells. Main findings were confirmed in serum samples of patients with post-traumatic sepsis.

MEASUREMENTS AND MAIN RESULTS

Procalcitonin-deficient mice are protected from septic shock and show decreased pulmonary inflammation. Mechanistically, procalcitonin potentiates proinflammatory cytokine expression in innate immune cells, required for interleukin-17A expression in gamma delta T cells. In patients with post-traumatic sepsis, procalcitonin positively correlates with systemic interleukin-17A levels. In mice with endotoxemia, immunoneutralization of interleukin-17A inhibits the deleterious effect of procalcitonin on disease outcome. Although calcitonin receptor expression is irrelevant for disease progression, the nonpeptide calcitonin gene-related peptide receptor antagonist olcegepant, a prototype of currently introduced antimigraine drugs, inhibits procalcitonin signaling and increases survival time in septic shock.

CONCLUSIONS

Our experimental data suggest that procalcitonin exerts a moderate but harmful effect on disease progression in experimental septic shock. In addition, the study points towards the calcitonin gene-related peptide receptor as relevant for procalcitonin signaling and suggests a potential therapeutic application for calcitonin gene-related peptide receptor inhibitors in sepsis, which warrants further clinical investigation.

An Innovative Pharmacometric Approach for the Simultaneous Analysis of Frequency, Duration and Severity of Migraine Events

PURPOSE

To explore the use of a multistate repeated, time-to-categorical event model describing the frequency, severity and duration of migraines.

METHODS

Subject level data from patients in placebo arms from two efficacy trials for migraine-preventive treatments were used. Models were developed using NONMEM 7.3. A survival model was combined with an ordered categorical model to form the repeated-time-to-start of categorical migraine event model, which simultaneously described the time-to-start of migraines and the severity of the starting migraine event. This was linked to a repeated-time-to-end of migraine event model with different hazard functions depending on the severity of the ongoing migraine event. Model performance was internally and externally qualified.

RESULTS

The successfully qualified model showed that patients responding to placebo had a reduction in migraine incidence rate, and a decreased proportion of severe migraines. There was an increase in moderate migraine duration, an increased proportion of mild migraines and a reduction in proportion of severe migraines. Age was related to migraine duration.

CONCLUSIONS

The model represents an innovative framework for clinical trial modeling and simulation, and successfully describes placebo effect in migraine prevention. This approach can be adapted to investigate exposure-response relationship of drugs and can also be implemented in other therapeutic areas where the rate, duration and severity of disease episodes are relevant to trial outcomes.

Efficacy and safety of galcanezumab for prevention of migraine headache in Japanese patients with episodic migraine: A phase 2 randomized controlled clinical trial

Objective:

This study was designed to assess the efficacy and safety of galcanezumab in comparison with placebo for the prevention of migraine in Japanese patients with episodic migraine.

Methods:

In this double-blind, placebo-controlled study, which was conducted over 6 months, randomized adult patients received subcutaneous injections of galcanezumab (120 mg n = 115, 240 mg n = 114) or placebo ( n = 230) once monthly. The primary endpoint was the overall mean change from baseline in the number of monthly migraine headache days. The key secondary outcome measures were response rates (≥50%, ≥75%, and 100%); the Migraine-Specific Quality-of-Life Questionnaire Role Function-Restrictive score; monthly migraine headache days requiring acute treatment; and Patient Global Impression of Severity (PGI-S).

Results:

The mean change from baseline in monthly migraine headache days over months 1–6 was significantly ( p < 0.001) greater for the 120-mg galcanezumab dose (−3.60 days) and the 240-mg galcanezumab dose (−3.36 days) compared with placebo (−0.59 days). Both the 120-mg and 240-mg doses of galcanezumab were superior compared with placebo for each of the key secondary endpoints except for PGI-S (only the 240-mg dose was superior). The most commonly reported treatment-emergent adverse events were local injection-site reactions; erythema, swelling, pruritus, and pain were more commonly reported by patients who were treated with galcanezumab than those treated with placebo.

Conclusion:

The number of monthly migraine headache days was reduced with both doses of galcanezumab, and both doses were safe and well tolerated in Japanese patients with episodic migraine.

A review of antibody-based therapeutics targeting G protein-coupled receptors: an update

INTRODUCTION

G protein-coupled receptors (GPCRs) play key roles in many biological functions and are linked to many diseases across all therapeutic areas. As such, GPCRs represent a significant opportunity for antibody-based therapeutics.

AREAS COVERED

The structure of the major GPCR families is summarized in the context of choice of antigen source employed in the drug discovery process and receptor biology considerations which may impact on targeting strategies. An overview of the therapeutic GPCR-antibody target landscape and the diversity of current therapeutic programs is provided along with summary case studies for marketed antibody drugs or those in advanced clinical studies. Antibodies in early clinical studies and the emergence of next-generation modalities are also highlighted.

EXPERT OPINION

The GPCR-antibody pipeline has progressed significantly with a number of technical developments enabling the successful resolution of some of the challenges previously encountered and this has contributed to the growing interest in antibody-based therapeutics addressing this target class.

Nonclinical safety evaluation of erenumab, a CGRP receptor inhibitor for the prevention of migraine

Calcitonin gene-related peptide (CGRP) and its receptor have been implicated as a key mediator in the pathophysiology of migraine. Thus, erenumab, a monoclonal antibody antagonist of the CGRP receptor, administered as a once monthly dose of 70 or 140 mg has been approved for the preventive treatment of migraine in adults. Due to the species specificity of erenumab, the cynomolgus monkey was used in the pharmacology, pharmacokinetics, and toxicology studies to support the clinical program. There were no effects of erenumab on platelets in vitro (by binding, activation or phagocytosis assays). Specific staining of human tissues with erenumab did not indicated any off-target binding. There were no erenumab-related findings in a cardiovascular safety pharmacology study in cynomolgus monkeys or in vitro in human isolated coronary arteries. Repeat-dose toxicology studies conducted in cynomolgus monkeys at dose levels up to 225 mg/kg (1 month) or up to 150 mg/kg (up to 6 months) with twice weekly subcutaneous (SC) doses showed no evidence of erenumab-mediated adverse toxicity. There were no effects on pregnancy, embryo-fetal or postnatal growth and development in an enhanced pre-postnatal development study in the cynomolgus monkey. There was evidence of placental transfer of erenumab based on measurable serum concentrations in the infants up to 3 months post birth. The maternal and developmental no-observed-effect level (NOEL) was the highest dose tested (50 mg/kg SC Q2W). These nonclinical data in total indicate no safety signal of concern to date and provide adequate margins of exposure between the observed safe doses in animals and clinical dose levels.