Pharmacometabonomic association of cyclophosphamide 4‐hydroxylation in hematopoietic cell transplant recipients

Abstract

The widely used alkylating agent cyclophosphamide (CY) has substantive interpatient variability in the area under the curve (AUC) of it and its metabolites.Numerous factors may influence the drug-metabolizing enzymes that metabolize CY to 4-hydroxycyclophosphamide (4HCY), the principal precursor to CY's cytotoxic metabolite. We sought to identify endogenous metabolomics compounds (EMCs) associated with 4HCY formation clearance (ratio of 4HCY/CY AUC) using global metabolomics. Patients who undergo hematopoietic cell transplantation receiving post-transplant CY (PT-CY) were enrolled, cohort 1 (n = 26) and cohort 2 (n = 25) donating longitudinal blood samples before they started HCT (pre-HCT), before infusion of the donor allograft (pre-graft), before the first dose of PT-CY (pre-CY), and 24 h after the first dose of PT-CY (24-h post-CY), which is also immediately before the second dose of CY. A total of 512 and 498 EMCs were quantitated in two cohorts, respectively. Both univariate linear regression with false discovery rate (FDR), and pathway enrichment analyses using a global association test were performed. At the pre-CY time point, no EMCs were associated at FDR less than 0.1. At pre-HCT, cohort 1 had one EMC (levoglucosan) survive the FDR threshold. At pre-graft, cohort 1 and cohort 2 had 20 and 13 EMCs, respectively, exhibiting unadjusted p values less than 0.05, with the only EMCs having an FDR less than 0.1 being two unknown EMCs. At 24-h post-CY, there were three EMCs, two ketones, and threitol, at FDR less than 0.1 in cohort 2. These results demonstrate the potential of pharmacometabonomics, but future studies in larger samples are needed to optimize CY. Study Highlights WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?We report the first pharmacometabonomic study of the association of plasma EMCs with cyclophosphamide pharmacokinetics, specifically the ratio of 4HCY/ CY AUC.

Lipidomics of cyclophosphamide 4‐hydroxylation in patients receiving post‐transplant cyclophosphamide

“…We previously evaluated an untargeted metabolomics panel and found 12 and 32 metabolites associated with pre‐CY administration for cohorts 1 and 2, respectively 13 . In pathway analyses, fatty acid metabolism was the only pathway identified prior to engraftment.…”

“…The PT‐CY dose was 50 mg/kg based on an adjusted ideal body weight (AIBW) IV [2‐h] infusion every 24 h for two doses, administered on HCT day +3 and +4. Pharmacokinetic samples were collected after each PT‐CY dose: at 2 (end of infusion), 4, 8, 20, and 24 h from the start of the infusion 13 . Concentrations of CY, 4HCY, carboxyethylphosphoramide mustard, deschloroethylcyclophosphamide, and 4‐ketocyclophosphamide were quantitated as previously reported, 13 using liquid‐chromatography tandem‐mass‐spectrometry (MS).…”

“…Pharmacokinetic samples were collected after each PT‐CY dose: at 2 (end of infusion), 4, 8, 20, and 24 h from the start of the infusion 13 . Concentrations of CY, 4HCY, carboxyethylphosphoramide mustard, deschloroethylcyclophosphamide, and 4‐ketocyclophosphamide were quantitated as previously reported, 13 using liquid‐chromatography tandem‐mass‐spectrometry (MS). The AUCs from time 0 h to 48 h were estimated using the trapezoidal numerical estimation function in MATLAB (v 2019a).…”

“…Within patients receiving PT‐CY, we previously characterized endogenous metabolomic compounds associated with the ratio of 4HCY/CY AUC 13 . Given the results suggesting alterations in fatty acid metabolism before engraftment, we furthered our search for biomarkers employing lipidomics in the same cohorts of patients receiving PT‐CY 13 .…”

“…Within patients receiving PT‐CY, we previously characterized endogenous metabolomic compounds associated with the ratio of 4HCY/CY AUC 13 . Given the results suggesting alterations in fatty acid metabolism before engraftment, we furthered our search for biomarkers employing lipidomics in the same cohorts of patients receiving PT‐CY 13 . Given their signaling properties in addition to a multitude of other functions, 14 lipidomics may enable a deeper mechanistic understanding of the pharmacokinetic disposition, drug–target interactions, and systems physiology from the molecular (genomic, proteomic, metabolomic) to cellular to whole‐body levels.…”