Comparing sGFAP and sNFl
This same principle was explored further in the latebreaking presentation by Ahmed Abdelhak, MD, a clinical instructor, Weill Institute for Neurosciences, University of California, San Francisco. The objective of his study was to compare sGFAP and sNFl for predicting PIRA in patients on treatment.
The study included 212 patients from the Swiss Multiple Sclerosis Cohort who were started on fingolimod or on B-cell depleting therapies like rituximab. After correcting for sex, age at onset, baseline Expanded Disability Status Scale (EDSS) scores, and other variables, Dr. Abdelhak also reported that the predictive values for PIRA were different for sGFAP relative to sNFl at least on the group level.
However, in this study, unlike the analysis of the Brigham MS Research Center data, changes in sGFAP over time when on treatment did have prognostic value, and there was a relationship between sGFAP levels and treatment. Although reductions in GFAP predicted less disability progression whether patients were treated with fingolimod B-cell depleting therapies, that patterns were different. Dr. Abdelhak, like the other investigators speaking at ECTRIMS, also said the data so far favor sGFAP over sNFl for predicting PIRA.
Each z-score unit change in sGFAP corresponded to a 47% lower risk of PIRA in follow-up over 6.8 years, Dr. Abdelhak reported, adding that the predictive value of sGFAP was “numerically stronger than the corresponding relation for sNFl.”
So far, clinical utility of sGFAP remains speculative. Most of the correlations he presented were on a group rather than the individual level. Moreover, Dr. Abdelhak cautioned that these correlations, based on observational data, do not necessarily reflect causation.
Nonetheless, remarking on the parallels of his data on sGFAP and sNFl with other studies presented at the ECTRIMS meeting, Dr. Abdelhak foresees a time when GFAP will be a prognostic tool, offering relative simplicity and lower cost than the current standard of imaging. He also sees a role in clinical research.
“Monitoring of sGFAP dynamics following DMT initiation could be used to prognosticate long-term PIRA risk and provide insights valuable for design and interpretation of trial outcomes,” he said.
Dr. Monreal reported financial relationships with Almirall, Biogen, Bristol-Myers Squibb, Janssen, Merck, Novartis, Roche, and Sanofi. Dr. Madill and Dr. Abdelhak reported no potential conflicts of interest.