Neurofilament light, a marker of neuroaxonal damage, is correlated with increased levels of disease progression and clinical relapses.
Recently, the FDA granted breakthrough device designation to Roche for its Elecsys Neurofilament Light Chain (NfL) test as a potential tool for the detection of disease activity in patients with multiple sclerosis (MS).1
NfL, a neuron-specific cytoskeletal protein that is released into the extracellular fluid following axonal injury, has been identified as a biomarker of disease activity in MS. Measurements of NfL levels can capture the extent of neuroaxonal damage, especially in the early stages of the disease. The Elecsys NfL test is intended for adults with MS aged 18 to 55 years old who have either relapsing-remitting or progressive forms of the disease.
"Around 2.8 million people are estimated to live with multiple sclerosis. After diagnosis, many face challenges with managing their disease due to significant gaps in access to testing. This can lead to missed opportunities to detect disease progression in support of treatment optimization," Matt Sause, chief executive officer of Roche Diagnostics, said in a statement.1 "We are excited about the potential Elecsys NfL has to improve outcomes for MS patients by offering a minimally invasive blood draw that can deliver rapid results."
Although the current spotlight for NfL’s intended use is MS, increases in NfL concentrations have been reported in a wide range of neurologic conditions including Alzheimer disease, amyotrophic lateral sclerosis (ALS), Huntington disease, and more. While Elecsys NfL is currently intended to provide insights on MS disease activity, Roche believes it has potential in assisting these other neurologic patient specialties.
Earlier this year, the FDA granted 510(k) clearance to Roche for its Alzheimer disease (AD) cerebrospinal fluid (CSF) Elecsys assays, which comprised of the beta-amyloid1-42 CSF II (Abeta42) and total tau (tTau) assay.2 Although intended for individuals ages 55 and older being evaluated for AD and other causes of cognitive impairment, a positive tTau/Abeta42 ratio result in CSF does not establish a diagnosis of AD. In AD, an early and accurate diagnosis can help patients, caregivers, and physicians determine a path forward and decide when treatment is most effective.
Previous research has shown that NfL levels in MS correlate with clinical relapses and radiologic biomarkers of inflammatory disease activity because they reflect the amount of gadolinium-enhancing lesions and the amount of paramagnetic rim MRI lesions in the absence of gadolinium-enhancing lesions. In addition, they also correlate with disease progression regarding the T2 lesion load, T2 lesion volume, and presence of atrophy in the brain and spinal cord.
In a 2022 study of brain donors with MS, active and mixed white matter lesions with foamy microglia showed high acute axonal damage and correlated with elevated CSF NfL levels. Similar to previous reported, CSF NfL levels correlated negatively with disease duration (P = 6.9e-3; r = .31). In donors without atrophy, CSF NfL levels correlated positively with the proportion of active and mixed lesions containing foamy microglia/macrophages (P = 9.85e-10 and P = 1.75e-3, respectively) but not with those containing ramified microglia.3