Researchers Report Best Times for Biomarker Assessment After NMOSD Attacks
The optimal times to assess serum glial fibrillary acidic protein (sGFAP) and serum neurofilament light chain (sNfL) when evaluating attacks in patients with neuromyelitis optica spectrum disorder (NMOSD) were within 1 week for sGFAP and 1 to 8 weeks for sNfL, according to study results published in JAMA Neurology.
“z Score cutoffs of 3.0 for sGFAP and 2.1 for sNfL effectively distinguished between attack and remission phases,” researchers reported, “indicated by area under the curve values of 0.95 (95% CI, 0.88-1.02) and 0.87 (95% CI, 0.82-0.91), respectively,” wrote first author Su-Hyun Kim, MD, PhD, of the Research Institute and Hospital of National Cancer Center, Goyang, Korea, and study coauthors.
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The study explored the temporal dynamics of sGFAP and sNfL as biomarkers of disease activity in NMOSD. The retrospective, longitudinal, multicenter investigation included 181 patients with aquaporin-4 antibody (AQP4-IgG)–positive NMOSD. Among the 78 Korean patients in the discovery cohort, there were 366 serum samples. The validation cohort included 190 samples from 34 German patients and 69 samples from 69 Brazilian patients.
In an analysis of temporal biomarker dynamics 6 months postattack involving 202 samples from 74 patients in the discovery cohort, levels of sGFAP peaked within the first week. Levels of sNfL peaked at 5 weeks after an attack, according to the study.
The best frames for evaluating attacks were within 1 week for sGFAP and between 1 and 8 weeks for sNfL, researchers reported. Remission was defined as at least 6 months postattack.
When applied to the validation cohort, the time frames and cutoff values achieved 71% sensitivity and 94% specificity for sNfL and 100% sensitivity and specificity for sGFAP.
“This longitudinal cohort study established optimal timing and thresholds for sGFAP and sNfL, which were consistent in independent cohorts, supporting these biomarkers’ effectiveness in distinguishing NMOSD attacks from remission,” researchers wrote.
