Twelve-month efficacy of CGRP monoclonal antibodies and predictive value of short-term response: results of an Australian multicentre study

Introduction

Clinical trials show that calcitonin gene-related peptide monoclonal antibodies (CGRP mAbs) are effective preventative treatments for chronic migraine. Their efficacy over longer time periods and in cohorts originally excluded from trials remains uncertain. This study aims to explore the impact of CGRP mAbs in an Australian real-life setting.

Methods

A multicentre cohort study was performed in the tertiary headache clinics of the Alfred and Austin Hospitals, Melbourne, Australia. Patients were commenced on a CGRP mAb for chronic migraine and asked to keep a headache diary, recorded at 3 monthly appointments for 12 months. Primary outcome was a ≥50% reduction in monthly headache days (MHD).

Results

From a population of 105 patients, 90 patients commenced galcanezumab and 15 commenced fremanezumab. The ≥50% responder rate of the cohort was 52.4% after 3 months. Over 12 months follow-up, 25.7% of the cohort ceased due to a lack of efficacy and 16.2% ceased due to an adverse event. There was no difference in response or cessation between medications. There was poor agreement in 3-month and 12-month response rates (Cohen's κ=0.130; p=0.171). On subgroup analysis, continuous headache at baseline and number of trialled preventative treatments were the only factors associated with efficacy.

Conclusion

CGRP mAbs were associated with sustained reductions in MHD over 12-month follow-up in patients with resistant migraine in Australia. Further studies are required to determine treatment options for patients with continuous headache. Poor agreement between outcomes at 3 and 12 months highlights the need to assess some patients at later timepoints.

IVIg-exposure and thromboembolic event risk: findings from the UK Biobank

BACKGROUND

Arterial and venous thromboembolic events (TEEs) have been associated with intravenous Ig use, but the risk has been poorly quantified. We aimed to calculate the risk of TEEs associated with exposure to intravenous Ig.

METHODS

We included participants from UK Biobank recruited over 3 years, data extracted September 2020.The study endpoints were incidence of myocardial infarction, other acute ischaemic heart disease, stroke, pulmonary embolism and other venous embolism and thrombosis.Predictors included known TEE risk factors: age, sex, hypertension, smoking status, type 2 diabetes mellitus, hypercholesterolaemia, cancer and past history of TEE. Intravenous Ig and six other predictors were added in the sensitivity analysis.Information from participants was collected prospectively, while data from linked resources, including death, cancer, hospital admissions and primary care records were collected retrospectively and prospectively.  FINDINGS: 14 794 of 502 492 individuals had an incident TEE during the study period. The rate of incident events was threefold higher in those with prior history of TEE (8 .7%) than those without previous history of TEE (3.0%).In the prior TEE category, intravenous Ig exposure was independently associated with increased risk of incident TEE (OR=3.69 (95% CI 1.15 to 11.92), p=0.03) on multivariate analysis. The number needed to harm by exposure to intravenous Ig in those with a history of TEE was 5.8 (95% CI 2.3 to 88.3).Intravenous Ig exposure did not increase risk of TEE in those with no previous history of TEE.

INTERPRETATION

Intravenous Ig is associated with increased risk of further TEE in individuals with prior history of an event with one further TEE for every six people exposed. In practice, this will influence how clinicians consent for and manage overall TEE risk on intravenous Ig exposure.

Calcitonin gene related peptide in migraine: current therapeutics, future implications and potential off-target effects

Migraine is the second largest cause of years lost to disability globally among all diseases, with a worldwide prevalence over 1 billion. Despite the global burden of migraine, few classes of therapeutics have been specifically developed to combat migraine. After 30 years of translational research, calcitonin gene-related peptide (CGRP) inhibitors have emerged as a promising new tool in the prevention of migraine. Like all new therapeutics; however, we have limited real-world experience and CGRP has several known systemic actions that warrant consideration. This article provides a narrative review of the evidence for CGRP antagonists and summarises the known and potential side effects that should be considered.

Fetuin in neurons of the retina and cerebellum during fetal and postnatal development of the rat

Although long known to be a liver-derived fetal plasma glycoprotein, fetuin has more recently been shown to be present in sub-populations of neurons in the developing nervous system of a number of mammalian species. We have extended these observations to examine the fetuin immunoreactivity (IR) in developing rat retina and cerebellum. Fetuin-IR was first seen in the retina on embryonic day (E)19 in a sub-population of cells in the retinal ganglion cell layer and a small proportion of cells in the neuroblastic layer. The proportion of cells in the ganglion layer exhibiting fetuin-IR increased until postnatal day (P)10 when all cells in this layer were strongly immunoreactive. From P14 onwards fetuin-IR was absent or very weak and restricted to a small proportion of ganglion cells. In the developing cerebellum, the outer and inner granule cell layers, the deep nuclei and cells in the sub-cortical white matter exhibited fetuin-IR from E19 to P10. There was little fetuin-IR in the cerebellum at ages P14 and older, and Purkinje cells did not exhibit fetuin-IR at any time. The results show that fetuin appears in many neurons in the retina and cerebellum that are differentiating during the period from E19 to P10. The concentration of fetuin in cerebrospinal fluid is at its highest in this same period which suggests that some sub-populations of neurons could obtain fetuin from extracellular fluid during this period; however, the lack of fetuin-IR in other neuronal populations suggests that fetuin uptake is not a general property of developing neurons.