Study Evaluating the Predictive Value of the Terminal Latency Index (TLI) for Treatment Response in Patients With Anti-MAG Neuropathy (PREDIMAG)

A Monocentric Retrospective Study Evaluating the Predictive Value of the Terminal Latency Index (TLI) for Treatment Response in Patients With Anti-MAG Neuropathy

"Anti-myelin-associated glycoprotein (anti-MAG) neuropathy is a rare dysimmune peripheral neuropathy, most commonly associated with an IgM monoclonal gammopathy. Its course is generally slow but may lead to significant functional disability. Despite therapeutic advances, including rituximab, intravenous immunoglobulins (IVIg), immunochemotherapy, and more recently Bruton tyrosine kinase inhibitors (BTKi), treatment response remains highly variable between patients. The Terminal Latency Index (TLI), an electrophysiological parameter reflecting distal demyelination, is a recognized diagnostic marker of anti-MAG neuropathy. However, its potential role as a predictive biomarker of treatment response remains insufficiently studied. Identifying a simple, reproducible, and readily available biomarker that could predict treatment response would be of major clinical importance for personalized patient management and optimization of therapeutic strategies. This monocentric retrospective study will analyze clinical, biological, and electrophysiological data from patients with anti-MAG neuropathy followed at Nice University Hospital (CHU de Nice) to assess the predictive value of baseline TLI for clinical response 12 months after treatment initiation."

Study Overview

• Status: Not yet recruiting
• Conditions: Peripheral Nervous System Disease; Anti-MAG Neuropathy; Anti-Myelin-Associated Glycoprotein Antibodie
• Intervention / Treatment: Diagnostic test: Electroneuromyography (ENMG) and Terminal Latency Index (TLI) Assessment

• Study Type: Observational
• Enrollment (Estimated): 100

Contacts and Locations

• Study Contact: Name: Abderhmane Slioui; Phone Number: +33 0492038953; Email: slioui.a@chu-nice.fr
• Study Contact Backup: Name: Mecheli Cavalli; Phone Number: +33 0492035435; Email: puma.ar@chu-nice.fr

Study Locations

• France
  • Alpes Maritimes
    • Nice, Alpes Maritimes, France, 06000
      • Chu de Nice
      • Contact: Angela Puma; Phone Number: +33 0492035435; Email: puma.ar@chu-nice.fr
      • Contact: Abderhmane de Nice; Phone Number: +33 0492038953; Email: slioui.a@chu-nice.fr

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

"Adult patients with documented anti-MAG activity-associated neuropathy, followed at the Reference Center for Rare Diseases of the Peripheral Nervous System at Nice University Hospital (CHU de Nice) between January 2005 and July 2025. Planned number of participants: 100 patients."

Description

Inclusion Criteria:

• Documented anti-MAG IgM polyneuropathy: positive anti-MAG antibodies, associated with an IgM monoclonal gammopathy, and a compatible clinical phenotype.
• Complete and interpretable baseline ENMG assessment: an initial electroneuromyography (ENMG) examination allowing reliable calculation of the TLI in at least two motor nerves among the right median, ulnar, and common fibular nerves.
• The examination must include the distal motor latency, proximal motor conduction velocity, and compound muscle action potential (CMAP).
• Treatment with at least one established therapeutic strategy: treatment initiated at the center, including intravenous immunoglobulins (IVIg), rituximab, immunochemotherapy, Bruton tyrosine kinase inhibitors (BTKi), and/or symptomatic treatment.
• Available functional clinical assessment: a documented INCAT disability score at two predefined time points: baseline (before treatment initiation) and 12 months (±2 months) after treatment initiation.
• Consent to participate in the study.

Exclusion Criteria:

• Peripheral neuropathy associated with an IgM monoclonal gammopathy, with strictly negative anti-MAG antibody testing or no available anti-MAG antibody measurement.
• Incomplete or uninterpretable ENMG data preventing accurate calculation of the TLI for the nerves of interest (median and ulnar nerves).
• Absence of a formally documented INCAT score at baseline or within the 12-month assessment window.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Anti-myelin-associated glycoprotein (anti-MAG) neuropathy; This monocentric retrospective observational study will include 100 patients with anti-myelin-associated glycoprotein (anti-MAG) neuropathy followed at Nice University Hospital (CHU de Nice). No additional intervention or modification of routine clinical care will be performed. Clinical, biological, therapeutic, and electrophysiological data will be retrospectively collected from medical records and available archives. Routinely performed electroneuromyography (ENMG) data will be analyzed, with particular emphasis on the Terminal Latency Index (TLI), calculated from available electrophysiological parameters according to the standard formula. The predictive value of baseline TLI for clinical response to treatment at 12 months will be assessed. Treatments received as part of routine care, including rituximab, IVIg, immunochemotherapy, and Bruton tyrosine kinase inhibitors (BTKi), will be recorded. No treatment will be assigned or modified by the study. Data will be pseudonymized and ent

Diagnostic test: Electroneuromyography (ENMG) and Terminal Latency Index (TLI) Assessment; This monocentric retrospective observational study will include 100 patients with anti-myelin-associated glycoprotein (anti-MAG) neuropathy followed at Nice University Hospital (CHU de Nice). No additional intervention or modification of routine clinical care will be performed. Clinical, biological, therapeutic, and electrophysiological data will be retrospectively collected from medical records and available archives. Routinely performed electroneuromyography (ENMG) data will be analyzed, with particular emphasis on the Terminal Latency Index (TLI), calculated from available electrophysiological parameters according to the standard formula. The predictive value of baseline TLI for clinical response to treatment at 12 months will be assessed. Treatments received as part of routine care, including rituximab, IVIg, immunochemotherapy, and Bruton tyrosine kinase inhibitors (BTKi), will be recorded. No treatment will be assigned or modified by the study. Data will be pseudonymized and ente

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Favorable Clinical Response at 12 Months (≥1-Point Decrease in INCAT Score)	Clinical response at 12 months, defined as a reduction of at least 1 point in the INCAT disability score from baseline. This outcome will be used to assess the predictive value of the baseline Terminal Latency Index (TLI) for treatment response in patients with anti-MAG neuropathy.	12 months after treatment initiation

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Predictive performance of TLI according to treatment strategy	Assessment of the predictive performance of baseline TLI for clinical response at 12 months, stratified according to the treatment strategy received.	12 months after treatment initiation.
Correlation between TLI, anti-MAG antibody titer, and INCAT score evolution	Assessment of the association between baseline TLI, quantitative anti-MAG antibody titer, and change in the INCAT disability score from baseline to 12 months.	Baseline to 12 months after treatment initiation
Optimal TLI threshold for predicting treatment response	Determination of the optimal baseline TLI threshold for predicting clinical response at 12 months using Receiver Operating Characteristic (ROC) curve analysis and the Youden index	Baseline to 12 months after treatment initiation

Collaborators and Investigators

• Sponsor: Centre Hospitalier Universitaire de Nice
• Investigators: Principal Investigator: Mecheli Cavalli

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): September 1, 2026
• Study Completion (Estimated): December 31, 2026

Study Registration Dates

• First Submitted: August 26, 2026
• First Submitted That Met QC Criteria: August 26, 2026
• First Posted (Actual): August 31, 2026

Study Record Updates

• Last Update Posted (Actual): August 31, 2026
• Last Update Submitted That Met QC Criteria: August 26, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Nervous System Diseases; Neuromuscular Diseases; Peripheral Nervous System Diseases; Diagnostic Techniques and Procedures; Diagnosis; Physical Examination
• Other Study ID Numbers: 26Neuro05

Drug and device information, study documents

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