Serum Neurofilaments in the Diagnosis of Amyotrophic Lateral Sclerosis (DIAGONALS)

Diagnostic Performance of Serum Neurofilaments in the Differential Diagnosis of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a serious neurodegenerative disease, often difficult to diagnose due to symptoms similar to other neurological pathologies. Diagnosis can take up to 14 months, although the rapid progression of the disease requires early detection. At present, there is no validated biomarker to aid diagnosis. Serum neurofilaments light chain (NfL), markers of neuronal degeneration, show great potential to help diagnose ALS early and assess disease severity. Recent research has shown that measurement of NfL in the blood can differentiate ALS from other neurological disorders, and new technologies are increasingly making it possible to perform these tests clinically.

The study hypothesis is that NfL blood levels, measured using clinical analyzers, could improve early ALS diagnosis, optimize patient recruitment for therapeutic trials and accelerate the assessment of treatment efficacy.

The primary objective is to evaluate the sensitivity and specificity of serum NfL for the diagnosis and differential diagnosis of amyotrophic lateral sclerosis (ALS) in newly recruited patients referred to the ALS Reference Center at Montpellier University Hospital. The diagnosis is established according to the revised El Escorial diagnostic criteria (see Appendix). This diagnosis is determined independently of the serum NfL concentration.

Study Overview

• Status: Not yet recruiting
• Conditions: Amyotrophic Lateral Sclerosis (ALS); Neurodegenerative Disorders; Motor Neuron Diseases
• Intervention / Treatment: Diagnostic test: Serum Neurofilament Serum NfL Measurement

Detailed Description

Amyotrophic lateral sclerosis (ALS) is one of the most severe neurodegenerative diseases. It is characterized by the progressive degeneration of upper and lower motor neurons, leading to progressive paralysis and ultimately death from respiratory failure, with a median survival ranging from 30 to 36 months following symptom onset (Hardiman et al., 2011). To date, no curative treatment is available, and the exact etiology of ALS remains largely unknown, except for the familial forms, which account for approximately 10% of cases.

Establishing an early diagnosis is essential to optimize patient management and reduce diagnostic delay, which is currently estimated at an average of 12 to 14 months (Paganoni et al., 2014). The diagnostic workup includes clinical examination, electroneuromyography, and additional complementary investigations. However, this diagnostic pathway remains highly variable among patients and may require several years before a definitive diagnosis is reached, as evidence of both upper and lower motor neuron involvement is present in only approximately 50% of patients at the initial consultation.

Furthermore, reliable prognostic assessment is not currently possible during the early stages of the disease, even when the diagnosis has been established. Improving prognostic evaluation therefore represents a major clinical challenge to provide appropriate information to patients and their families.

To date, no validated biomarker is available to assist clinicians in the rapid differential diagnosis of ALS or to accurately predict disease severity at an early stage (Lenglet and Camdessanche, 2017).

Neurofilaments (Nf), which are major structural components of the neuronal cytoskeleton, are released into the cerebrospinal fluid (CSF) and subsequently into the bloodstream during neurodegenerative processes, including ALS (Bridel et al., 2019). The diagnostic value of neurofilament light chain (NfL) measurements in CSF for the differential diagnosis of ALS has already been demonstrated in various clinical settings, including prospective studies (Li et al., 2018).

The ultrasensitive Single Molecule Array (SIMOA) technology, initially available at the Department of Clinical Biochemistry and the Clinical Proteomics Platform (LBPC/PPC, Montpellier University Hospital), enabled the quantification of NfL concentrations in both CSF and blood samples. NfL levels measured in these biological fluids have been shown to correlate with patient survival (Poesen and Van Damme, 2018; Thouvenot et al., 2019; Brousse et al., 2022).

However, most published studies have been retrospective in nature. In addition, with the exception of the recent work by Brousse et al. (2022), blood samples were generally not collected during the early phase of the disease.

The present study offers several innovative features. It is conducted prospectively under real-world clinical conditions. All patients referred to the ALS Reference Center at Montpellier University Hospital for suspected ALS are included, regardless of the final diagnosis.

Historically, SIMOA technology was used for research purposes ("Research Use Only", RUO) to quantify serum NfL and glial fibrillary acidic protein (GFAP). Validated assays providing comparable analytical performance are now available on fully automated clinical analyzers, including Lumipulse and Cobas platforms, which have replaced SIMOA for routine laboratory use.

GFAP is predominantly expressed by astrocytes within the central nervous system and plays a key role in several biological processes, including cell communication and maintenance of the blood-brain barrier. Increased GFAP concentrations have been associated with astroglial activation, a mechanism implicated in ALS pathophysiology and linked to poor prognosis. However, recent findings (Mondesert et al., in preparation) suggest that GFAP concentrations do not significantly change during the course of ALS.

Accordingly, the present project focuses on the prospective clinical validation of blood NfL measurements obtained under routine clinical practice conditions. This objective represents an important step toward complementing existing retrospective evidence and confirming the clinical utility of NfL as a biomarker.

Ultimately, the prospective implementation of NfL measurements is expected to improve both the diagnostic and prognostic value of this biomarker while facilitating patient selection and monitoring in future therapeutic clinical trials for amyotrophic lateral sclerosis.

• Study Type: Observational
• Enrollment (Estimated): 138

Contacts and Locations

• Study Contact: Name: Elisa DE LA CRUZ, MD; Phone Number: +33 04 67 33 02 81; Email: e-delacruz@chu-montpellier.fr
• Study Contact Backup: Name: Florence ESSELIN, MD; Phone Number: +33 04 67 33 75 05; Email: f-esselin@chu-montpellier.fr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Probability Sample

Study Population

The study population consists of all patients referred to the rare disease reference center for amyotrophic lateral sclerosis (ALS) at CHU Montpellier for suspected ALS, regardless of the final diagnosis. These patients will be included prospectively as part of the diagnostic evaluation. The inclusion will be based on clinical suspicion of ALS, and the final diagnosis will be established according to the revised El Escorial criteria, independent of the NfL serum levels. This population will be monitored and analyzed for diagnostic performance and prognostic value of serum NfL levels.

Description

Inclusion Criteria:

• Be at least 18 years of age
• Be able to undergo blood sampling (however, blood sampling is part of the standard examination and will not be performed exclusively for this study).
• Patients with suspected ALS

Exclusion Criteria:

-• Patients with recent stroke

• Pregnant or breast-feeding women
• Patient deprived of liberty by judicial or administrative decision, or hospitalization under duress
• Adult protected by law (guardianship, curatorship)
• Patient unable to understand and read information and consent forms in French
• Person participating in another research study with an exclusion period still in progress.
• Failure to obtain written informed consent after a period of reflection
• Not affiliated to a social security scheme or beneficiary of such a scheme
• Person unable to give consent

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Patients Suspected of ALS; This group of patients includes those with a suspected diagnosis of ALS and referred to the CHU Montpellier reference center. The study focuses on measuring serum levels of neurofilament light (NfL), a biomarker of neuronal damage, to assess its ability to diagnose ALS and predict disease progression, survival and timing of initiation of non-invasive ventilation (NIV).

Diagnostic test: Serum Neurofilament Serum NfL Measurement; The procedure involves taking an additional 6 ml blood sample (dry tube) during the first visit, in addition to the routine sample taken for diagnostic investigations. Serum levels of neurofilament light chain (NfL), a biomarker of neuronal damage, will be measured using ultrasensitive techniques (SIMOA, Lumipulse, Cobas). The aim is to assess the diagnostic performance of NfL levels in differentiating ALS from other neurodegenerative diseases, as well as their prognostic value in terms of survival and disease progression.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Evaluate the diagnostic performance of blood NfL levels for the diagnosis of ALS	Evaluate the diagnostic performance of blood NfL levels for the diagnosis of ALS. Evaluation of the diagnostic performance of NfL blood levels (pg/mL) on samples taken during the patient inclusion visit. The final diagnosis will be established independently of the serum NfL levels at inclusion. The ALS diagnosis will be made according to the revised El Escorial criteria, which distinguish between definite, probable, clinically probable with paraclinical support, or possible ALS diagnoses.	From baseline (Visit 0) up to 12 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Functional decline	ALS Functional Rating Scale - Revised (ALSFRS-r) is administered regularly to evaluate the patient's functional decline, which will be correlated with serum NfL levels to assess the prognostic value of NfL in predicting disease progression.	From enrollment to the end of follow-up, at least every 3 months during routine clinical care.
Respiratory function	Pulmonary Function Test. FVC and SVC are important indicators of respiratory function, which typically declines as ALS progresses. These values will be correlated with NfL levels to investigate how early changes in NfL relate to respiratory decline.	From enrollment to the end of follow-up, at least every 3 months during routine clinical care.
Initiation of non-invasive ventilation	The need for NIV will be monitored and correlated with serum NfL levels to determine whether elevated NfL levels correlate with an earlier need for NIV, suggesting a more rapid disease progression.	From enrollment to the end of follow-up, at least every 3 months during routine clinical care.
Overall survival	This endpoint will examine the correlation between serum NfL levels and patient survival. The hypothesis is that higher levels of NfL could correlate with shorter survival times due to more rapid neurodegeneration.	From enrollment to the end of follow-up, at least every 3 months during routine clinical care.

Collaborators and Investigators

• Sponsor: University Hospital, Montpellier
• Investigators: Principal Investigator: Elisa DE LA CRUZ, MD, University Hospital, Montpellier

Study record dates

Study Major Dates

• Study Start (Estimated): August 1, 2026
• Primary Completion (Estimated): August 1, 2027
• Study Completion (Estimated): August 1, 2028

Study Registration Dates

• First Submitted: July 10, 2026
• First Submitted That Met QC Criteria: July 10, 2026
• First Posted (Actual): July 15, 2026

Study Record Updates

• Last Update Posted (Actual): July 15, 2026
• Last Update Submitted That Met QC Criteria: July 10, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: amyotrophic lateral sclerosis; early diagnosis; neurofilament proteins; glial fibrillary acid protein
• Additional Relevant MeSH Terms: Central Nervous System Diseases; Nervous System Diseases; Pathologic Processes; Neuromuscular Diseases; Metabolic Diseases; Spinal Cord Diseases; TDP-43 Proteinopathies; Proteostasis Deficiencies; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Disease; Motor Neuron Disease; Amyotrophic Lateral Sclerosis; Neurodegenerative Diseases
• Other Study ID Numbers: RECHMPL22_0075; 2022-A01792-41 (Other Identifier: CHU Montpellier)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No