Evaluation of Lyso-Gb1 as a biomarker for Gaucher disease treatment outcomes using data from the Gaucher Outcome Survey

BackgroundPatients with Gaucher disease (GD) require continual monitoring; however, lack of specific disease biomarkers was a significant challenge in the past. Glucosylsphingosine (lyso-Gb1) has been shown to be a reliable, key, specific, and sensitive biomarker for diagnosis, prognosis, and treatment response in clinical studies of patients with GD. We evaluated the change in lyso-Gb1 concentration over time following enzyme replacement therapy in patients with confirmed GD using real-world data from the Gaucher Outcome Survey disease registry.MethodsData for patients aged >= 18 years with a confirmed diagnosis of GD and at least two lyso-Gb1 assessments were analyzed retrospectively. Patients were stratified by treatment status at baseline (time of first lyso-Gb1 assessment). Lyso-Gb1 concentrations were measured from dried blood spot (DBS) samples by Centogene AG. Assessments included change in lyso-Gb1 concentration, hemoglobin concentration, platelet counts, and spleen and liver volume from baseline to the last lyso-Gb1 assessment.ResultsOf 2007 patients enrolled in the Gaucher Outcome Survey as of February 25, 2022, 435 met the inclusion criteria and were included in the study: 318 treated ('all treated'; 277 receiving treatment at baseline, 41 treatment naive at baseline), 38 receiving treatment at baseline who stopped treatment before the last lyso-Gb1 assessment, and 79 untreated. Lyso-Gb1 concentrations decreased from baseline to the last lyso-Gb1 assessment for all treated patients (median change - 8.6 ng/mL), and increased for untreated patients (median change 25.0 ng/mL) and those who stopped treatment (median change 19.5 ng/mL). Decreases were greater for all treatment-naive than previously treated patients (median change - 120.5 vs. - 3.3 ng/mL) and for velaglucerase alfa-treated patients vs. the overall treated cohort (-32.6 vs. - 8.6 ng/mL). Small improvements in hemoglobin concentrations, platelet counts, and spleen volume were observed for treated patients but not untreated/stopped treatment cohorts.ConclusionsIn this study, changes in lyso-Gb1 concentrations from DBS were reflective of responses to enzyme replacement therapy initiation or withdrawal in most patients. These findings confirm that the use of DBS samples for routine monitoring of lyso-Gb1 concentrations in patients with GD is feasible in real-world settings and may be useful to assess treatment response.