The 7th Annual Meeting of the European Academy of Neurology (EAN) - the largest neurology congress in Europe - was held virtually between the 19th and 22nd June 2021 and drew over 11,000 participants. The overarching theme of this year’s congress was ‘Towards Precision Neurology’, reflecting a focus on current and future use of precise tools such as genetics, imaging and omics for the diagnosis and personalised treatment of neurological disorders.
EAN President Claudio Bassetti, Bern, Switzerland, began the opening plenary session by reviewing key activities and future initiatives across the EAN’s four main pillars - science, education, membership and advocacy/communication. The vision of EAN is to be the home and voice of neurology in Europe, with a mission to reduce the overall burden of brain diseases. The ‘Big 6’ is a new EAN theme focused on key steps for the promotion/preservation of brain health and prevention of neurological diseases.
The 'Big 6' is a new EAN theme
“The spread of COVID-19 has not only profoundly changed our lives and habits but has also pushed us to discover innovative ways of working and interacting, while also stimulating a great amount of scientific activity.”
Raphaela Goldbach-Mansky, Bethesda, MD, USA
The opening lecture of EAN 2021 was delivered by Juergen Knoblich, Vienna, Austria, and explored insights from the laboratory that may profoundly influence how neurology research is conducted in the future. To combat the difficulties of murine modelling, cerebral organoids have been developed which can be used to model human brain development and recapitulate neurodevelopmental disorders in stem cell derived 3D cultures.
“The human brain is the most complex and most fascinating organ that mother nature has created - but this complexity comes at a price as the brain is also home to some of the most devastating disorders.”
Juergen Knoblich, Vienna, Austria
MOVEMENT AND NEUROMUSCULAR DISORDERS
Updates in innovative diagnostic methods for Parkinson’s disease (PD) and other synucleinopathies
Imaging for PD and parkinsonism was reviewed by Irena Rektorova, Brno, Czech Republic, who explained that early prodromal diagnosis of PD is possible using imaging modalities such as dopamine transporter (DaT) scan, fluorodeoxyglucose positron emission tomography (FDG PET) for PD-related pattern (PDRP) expression and neuromelanin/iron sensitive MRI. Diffusion techniques such as free water imaging and diffusion kurtosis imaging have also proven sensitive for early diagnosis. For the differential diagnosis of parkinsonism, options include specific MRI markers such as the magnetic resonance parkinsonism index (MRPI) or detection of free water in the basal ganglia or other structures (such as CRBL or thalamus). FDT PET pattern expression or automated categorisation using structural MRI are also key differential diagnostic tools.
“The DaT scan is able to predict conversion to symptomatic Parkinson’s disease within 3–5 years.”
Irena Rektorova, Brno, Czech Republic
Alessio Barnaba Di Fonzo, Milan, Italy, highlighted the important role of gene testing in the management of PD, in particular for predicting the course of the disease and guiding decisions on treatment initiation. Genetic analysis can also aid in diagnosis, however Dr Di Fonzo stressed the importance of combining this with phenotype data from neuroimaging and information such age of onset and prominent clinical features to ensure diagnostic accuracy. In the modern era of precision medicine, genetics is essential for enrolling patients with PD into clinical trials of therapies targeted at specific mutations (e.g. venglustat and ambroxol for glucocerebrosidase [GBA] and leucine rich repeat kinase 2 [Lrrk2] inhibitors for Lrrk2). Moving forward, genetic testing may additionally be used to identify large families with no known mutations in order to perform linkage analysis and exome sequencing.
Frequency of gene mutations in PD
Laboratory biomarkers for the diagnosis of PD, other synucleinopathies and atypical parkinsonian syndromes were explored by Per Svenningsson, Stockholm, Sweden. GBA is a recognised genetic risk maker for PD and acts as a biomarker for cognitive decline. Predictive biofluid biomarkers of PD dementia have also been identified, notably low levels of Aβ1-42 in the CSF which appears linked to development of dementia in patients with PD. From a diagnostic perspective, α-synuclein aggregation measured by RT-QuiC acts as a specific and sensitive CSF biomarker for PD. High levels of neurofilament light in either the CSF or the serum can also aid in differential diagnosis by helping to distinguish PD from atypical parkinsonism.
Tiago Fleming Outeiro, Goettingen, Germany, described the pathological spreading of α-synuclein as a critical aspect of PD which may open the door to novel disease biomarkers and targets for intervention. Based on the hypothesis that synucleinopathies are ‘prion-like diseases’ the process of α-synuclein aggregation may be non-linear and follow different pathways depending on conditions and cellular environment. The same initial form of α-synuclein may therefore lead to slightly different types of amyloid fibrils associated with different disease pathologies. Recent evidence suggests that α-synuclein pathology spreads through the brain connectome and is modulated by different genes and environmental factors. However, question marks surround whether the original alpha-synuclein pathology originates in the brain, the body or even in the gut.
“Current therapies focus on the clinical symptoms of PD but by understanding causes such as the aggregation process and the spreading of pathology we may be able to tackle the origins of the disease.”
Tiago Fleming Outeiro, Goettingen, Germany
Precision medicine in PD
Oliver Bandmann, Sheffield, UK, explained that different approaches to disease stratification in PD are under exploration to develop a precision medicine approach for future DMT. Evidence indicates that both mitochondrial and lysosomal dysfunction are key mechanisms in the pathogenesis of sporadic PD, while genetic risk factors include GBA and Lrrk2 mutations. In the future, it will be important to synchronise clinical stratification with gene and biomarker-based stratification to enable individualised treatment selection based on PD subtype, he concluded.
Potential strategies for disease stratification in PD
Personalised management of PD with device-aided therapies was examined by Regina Katzenschlager, Vienna, Austria, focusing on infusion therapies for continuous dopaminergic drug delivery and surgical deep brain stimulation (DBS). She described both as highly efficacious treatment options for patients with persistent motor fluctuations which should be considered as soon as symptoms become difficult to manage. Selection for each patient must be based on individual criteria but ultimately determined by personal choice.
Clinical use of stem cells in movement disorders
During this ‘controversy’ session, Anders Bjorkland, Lund, Sweden, argued that stem cells are ready for clinical use and, based on available evidence, hold great promise for dopamine cell replacement therapy in patients with PD. However, he cautioned that progress in the field must be taken with great care and should proceed in a cautious, stepwise manner.
Joaquim Ferreira, Lisbon, Portugal, took the opposing stance, stating that - although biologically and technologically feasible - the optimal preparation and implant protocols for stem cells are not yet clear. Only a symptomatic or partial effect may be induced which is insufficient to halt or delay disease progression. Key safety issues also remain unknown and critical logistical/standardisation aspects are yet to be finalised.
“We are at the very early therapeutic development stage with stem cells and not ready to start using these in the clinic.”
Joaquim Ferreira, Lisbon, Portugal
Beyond the prion principle
In the Presidential Lecture entitled ‘History of Prion Science’ Adriano Aguzzi, Zurich, Switzerland, outlined how the pathogenesis of a number of different neurological diseases follows a similar sequence of protein aggregation events that occurs in prion diseases. These potential ‘prionoids’ and their associated pathogenic proteins include AD (amyloid-β), tauopathies (tau), Parkinson’s disease (PD; aggregated and phosphorylated α-synuclein; Lewy bodies) and Huntington’s disease (HD; polyglutamine).
Experimental therapies for HD
Anne Rosser, Cardiff, UK, described how progress in HD has led to several potential DMTs in clinical trials or on the horizon which are underpinned by a strong biological rationale. Significant focus has been directed towards lowering levels of the mutant Huntingtin protein. The pivotal phase 3 Generation HD1 trial of the antisense oligonucleotide (ASO) tominersen - the largest-ever interventional study in HD - was stopped in March 2021 based on unfavourable safety and efficacy trends compared with the placebo arm over time. Other non-ASO strategies include Unicure’s trial to deliver microRNA direct into the striatum through a neurosurgical procedure; DNA-targeted treatments such as zinc finger transcriptional repressors; and, oral preparations that act on RNA splicing.
Experimental therapeutic approaches for HD
Experimental therapeutic approaches for HD
In a non-protein strategy that instead targets somatic CAG expression, Triplet Therapeutics are exploring ASOs to knockdown specific DNA repair enzymes in the brain with a clinical trial due to starting soon. In the field of cell therapy, preliminary evidence indicates that neural transplantation of foetal derived cells can improve motor function and cognition in patients with HD. The TRIDENT study (ISRCTN 52651778) will explore this paradigm further.
Motor neuron diseases in infancy and childhood: new treatments
These are ‘exciting’ and ‘dynamic’ times in spinal muscular atrophy (SMA) said Francesco Muntoni, London, UK, with three effective therapies now approved. The size of the response to intervention is expected to be transformative for patients, especially if treated early, providing a strong argument for the implementation of newborn screening. Dr Muntoni acknowledged that comparing the efficacy of available therapies is difficult and each approach has specific pros and cons. Differences in the slope of initial response have been seen in some SMA type 1 trials but the longer-term impact of this remains unclear. Available data also suggest that some drugs - notably risdiplam and AVXS-101 - could be associated with a better bulbar function in SMA type 1, remarked Dr Muntoni.
Pros and cons of SMA therapeutic approaches
Congress highlights in SMA
In closing, Programme Committee Chair, Tony Marson, Liverpool, UK, explained that plans are already well developed for the 8th Annual EAN congress which will take place in Vienna, Austria under the overarching theme ‘Getting Evidence into Practice’. We very much hope this will be an in-person event, stressed Dr Marson but contingency plans are in place for a hybrid congress or reversion to a virtual congress if required.
“The aim for 2022 is to have a congress that represents the whole of Europe with a pan-European flavour. It will be a celebration that we can finally come together again after this really challenging time with the COVID-19 pandemic.”
Tony Marson, Liverpool, UK
©Springer Healthcare 2021. This content has been independently selected and developed by Springer Healthcare and licensed by Roche for Medically. The topics covered are based on therapeutic areas specified by Roche. Inclusion or exclusion of any product does not imply its use is either advocated or rejected. Use of trade names is for product identification only and does not imply endorsement. Opinions expressed do not reflect the views of Springer Healthcare. Springer Healthcare assumes no responsibility for any injury or damage to persons or property arising out of, or related to, any use of the material or to any errors or omissions. Please consult the latest prescribing information from the manufacturer for any products mentioned in this material.