TY - JOUR
T1 - 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)
AU - Pandey, Renu
AU - Gruslova, Aleksandra
AU - Chiou, Jennifer
AU - Brenner, Andrew J.
AU - Tiziani, Stefano
N1 - Funding Information:
This work was supported by University of Texas System grant (ST: STAR Award). We acknowledge Immunomedics, Inc., Morris Plains, NJ, for the supply of sacituzumab govitecan.
Publisher Copyright:
Copyright © 2019 American Chemical Society.
PY - 2020/1/7
Y1 - 2020/1/7
N2 - 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.
AB - 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.
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U2 - 10.1021/acs.analchem.9b04419
DO - 10.1021/acs.analchem.9b04419
M3 - Article
C2 - 31765123
AN - SCOPUS:85076626823
VL - 92
SP - 1260
EP - 1267
JO - Analytical Chemistry
JF - Analytical Chemistry
SN - 0003-2700
IS - 1
ER -