Stable Isotope Dilution LC-HRMS Assay To Determine Free SN-38, Total SN-38, and SN-38G in a Tumor Xenograft Model after Intravenous Administration of Antibody–Drug Conjugate (Sacituzumab Govitecan)

Antibody–drug conjugates (ADCs) have gained significant interest over the past few years due to their targeted delivery, higher efficacy, decreased toxicity and improved therapeutic index over conventional anticancer therapies. Sacituzumab govitecan (SG) is an ADC composed of a Trop-2-targeted antibody conjugated to the cytotoxic payload SN-38. SG is currently being evaluated in clinical trials of several solid cancers. In this nonclinical study, we have developed a highly sensitive and selective approach to measure free and total SN-38 and its glucuronidation metabolite (SN-38G) using stable isotope dilution (SID) ultrahigh-performance liquid chromatography–high resolution mass spectrometry (UHPLC-HRMS). An efficient and fast hydrolysis procedure (2 h at 100 °C) was established to release SN-38, conjugated to the antibody by carbonate linkage. The assay involves the extraction of free SN-38, SN-38G by protein precipitation, and subsequent acid hydrolysis of the protein layer to release antibody-bound SN-38. The developed UHPLC-HRMS method resulted in good linearity (r2 ≥ 0.997), accuracy (RE ≤ ± 9.1%), precision (CVs ≤ 7.7%), and extraction recoveries (85.6–109.3%). The validated method was applied in the plasma and tumor of mice bearing human brain (U251) and breast (MDA-MB-468) tumor xenografts treated with a single dose (0.5 mg) of SG for 6 h. Results revealed the presence of trace level of SN-38G and free SN-38 in plasma, which suggests an improved therapeutic index of SG. The established method makes a significant contribution to the assessment of SG in different cancers

DataSheet_2_Circulating metabolites associated with tumor hypoxia and early response to treatment in bevacizumab-refractory glioblastoma after combined bevacizumab and evofosfamide.pdf

Glioblastomas (GBM) are the most common and aggressive form of primary malignant brain tumor in the adult population, and, despite modern therapies, patients often develop recurrent disease, and the disease remains incurable with median survival below 2 years. Resistance to bevacizumab is driven by hypoxia in the tumor and evofosfamide is a hypoxia-activated prodrug, which we tested in a phase 2, dual center (University of Texas Health Science Center in San Antonio and Dana Farber Cancer Institute) clinical trial after bevacizumab failure. Tumor hypoxic volume was quantified by 18F-misonidazole PET. To identify circulating metabolic biomarkers of tumor hypoxia in patients, we used a high-resolution liquid chromatography-mass spectrometry-based approach to profile blood metabolites and their specific enantiomeric forms using untargeted approaches. Moreover, to evaluate early response to treatment, we characterized changes in circulating metabolite levels during treatment with combined bevacizumab and evofosfamide in recurrent GBM after bevacizumab failure. Gamma aminobutyric acid, and glutamic acid as well as its enantiomeric form D-glutamic acid all inversely correlated with tumor hypoxia. Intermediates of the serine synthesis pathway, which is known to be modulated by hypoxia, also correlated with tumor hypoxia (phosphoserine and serine). Moreover, following treatment, lactic acid was modulated by treatment, likely in response to a hypoxia mediated modulation of oxidative vs glycolytic metabolism. In summary, although our results require further validation in larger patients’ cohorts, we have identified candidate metabolic biomarkers that could evaluate the extent of tumor hypoxia and predict the benefit of combined bevacizumab and evofosfamide treatment in GBM following bevacizumab failure.</p

DataSheet_1_Circulating metabolites associated with tumor hypoxia and early response to treatment in bevacizumab-refractory glioblastoma after combined bevacizumab and evofosfamide.docx

Glioblastomas (GBM) are the most common and aggressive form of primary malignant brain tumor in the adult population, and, despite modern therapies, patients often develop recurrent disease, and the disease remains incurable with median survival below 2 years. Resistance to bevacizumab is driven by hypoxia in the tumor and evofosfamide is a hypoxia-activated prodrug, which we tested in a phase 2, dual center (University of Texas Health Science Center in San Antonio and Dana Farber Cancer Institute) clinical trial after bevacizumab failure. Tumor hypoxic volume was quantified by 18F-misonidazole PET. To identify circulating metabolic biomarkers of tumor hypoxia in patients, we used a high-resolution liquid chromatography-mass spectrometry-based approach to profile blood metabolites and their specific enantiomeric forms using untargeted approaches. Moreover, to evaluate early response to treatment, we characterized changes in circulating metabolite levels during treatment with combined bevacizumab and evofosfamide in recurrent GBM after bevacizumab failure. Gamma aminobutyric acid, and glutamic acid as well as its enantiomeric form D-glutamic acid all inversely correlated with tumor hypoxia. Intermediates of the serine synthesis pathway, which is known to be modulated by hypoxia, also correlated with tumor hypoxia (phosphoserine and serine). Moreover, following treatment, lactic acid was modulated by treatment, likely in response to a hypoxia mediated modulation of oxidative vs glycolytic metabolism. In summary, although our results require further validation in larger patients’ cohorts, we have identified candidate metabolic biomarkers that could evaluate the extent of tumor hypoxia and predict the benefit of combined bevacizumab and evofosfamide treatment in GBM following bevacizumab failure.</p

Additional file 4 of Serine, N-acetylaspartate differentiate adolescents with juvenile idiopathic arthritis compared with healthy controls: a metabolomics cross-sectional study

Additional file 4: Supplementary Table 1. Reported Intake of One or More Medications or Supplements within Each Category within 7 Days Prior to Study Visit. Supplementary Table 2. Overview of Literature about the Role of Serine Metabolism in Arthritis and Related Conditions (plasma serine or serum serine or circulating serine or L-serine) AND (arthritis) AND (metabolome or metabolomics or metabolite). Supplementary Table 3. Overview of Brain Tissue N-Acetylaspartate Literature about Arthritis and Related Diseases

Additional file 3 of Serine, N-acetylaspartate differentiate adolescents with juvenile idiopathic arthritis compared with healthy controls: a metabolomics cross-sectional study

Additional file 3: Supplementary Fig. 2. Glyoxylate and Dicarboxylate Pathway Comparing Plasma Metabolites: Juvenile Idiopathic Arthritis Relative to Controls

Additional file 1 of Serine, N-acetylaspartate differentiate adolescents with juvenile idiopathic arthritis compared with healthy controls: a metabolomics cross-sectional study

Additional file 1: Supplementary File 1. R Code Used for Statistical Analyses

Additional file 2 of Serine, N-acetylaspartate differentiate adolescents with juvenile idiopathic arthritis compared with healthy controls: a metabolomics cross-sectional study

Additional file 2: Supplementary Fig. 1. Citrate Cycle Comparing Plasma Metabolites by Group: Juvenile Idiopathic Arthritis Relative to Controls