Development and application to clinical practice of a validated HPLC method for the analysis of β-glucocerebrosidase in Gaucher disease

Quantitative assessment of the exposure–efficacy relationship of glucocerebrosidase using Markovian elements in Gaucher patients treated with enzyme replacement therapy

“…The lysosomal glucocerebrosidase-specific (GBA 1 ) method consisted of an acid hydrolysis reaction between enzyme and 4-nitrophenyl-β-D-glucopyranoside at pH 4.5 using plasma and leukocyte aliquots, leading to 4-nitrophenol, which was determined by high performance liquid chromatography (HPLC) coupled with ultraviolet (UV) detection. 20 The lysosomal glucocerebrosidase-unspecific (GBA 1 , GBA 2 and GBA 3 ) method, which has demonstrated a good correlation with clinical response to ERT, 21 implemented with an aliquot of leukocytes was used in an enzymatic reaction between enzyme and a solution of 4-methylumbellferyl-β-D-glucoside at pH 5.4. The product of the enzymatic reaction (4-methylumbelliferone) was determined by HPLC coupled with fluorometric (FLUO) detection.…”

“…This analytical method by HPLC has been proposed as the gold‐standard methodology for enzyme quantification, 40,41 and has been used in most of the enzyme pharmacokinetic studies 36,42–44 . The specificity of the analytical method for GBA 1 20,36 or GCase, which includes endogenous synthesis of GBA 1 , GBA 2 and GBA 3 and exogenous uptake of rGBA 1 from ERT administration, has been reported in several publications 30 . In this study, the measurement of GCase activity was selected for the exposure–efficacy model instead of GBA 1 .…”

“…S-MRI is an accurate score which detects fine, qualitative, perceptible changes in the bone marrow of patients with GD and improves the assessment prior to and during ERT, identifying GD complications as well. [16][17][18] Pharmacokinetic-biomarker analyses based on GCase activity in leukocytes have demonstrated a good correlation with clinical response to ERT [19][20][21] and a pharmacokinetic/pharmacodynamic (PK/PD) model in intra-monocyte GBA 1 data allowed better understanding of its properties. 22 Moreover, ERT is effective in improving bone marrow involvement, but no exposure-response relationship of ERT in bone marrow has been established so far.…”

“…Pharmacokinetic‐biomarker analyses based on GCase activity in leukocytes have demonstrated a good correlation with clinical response to ERT 19–21 and a pharmacokinetic/pharmacodynamic (PK/PD) model in intra‐monocyte GBA 1 data allowed better understanding of its properties 22 . Moreover, ERT is effective in improving bone marrow involvement, but no exposure–response relationship of ERT in bone marrow has been established so far 23,24 .…”

Relationship Between Glucocerebrosidase Activity and Clinical Response to Enzyme Replacement Therapy in Patients With Gaucher Disease Type I

“…Published studies on the pharmacokinetics of ERT have suggested that, after intravenous administration, the activity of circulating enzyme decreases rapidly in plasma because the principal distribution model of the ERT is through uptake by mannose‐6‐phosphate (M6P) into peripheral monocytes and their distribution in tissues as macrophages. A direct extravasation to tissues through the vascular endothelium with subsequent uptake by macrophages is theoretically less important or null due to its high molecular weight (70 KDa), which causes the tissue distribution of most proteins to be limited to the vascular or interstitial spaces .…”