A rapid urine test for early detection of kidney injury.

Kidney injury molecule-1 (Kim-1) has been qualified by the Food and Drug Administration and European Medicines Agency as a highly sensitive and specific urinary biomarker to monitor drug-induced kidney injury in preclinical studies and on a case-by-case basis in clinical trials. Here we report the development and evaluation of a rapid direct immunochromatographic lateral flow 15-min assay for detection of urinary Kim-1 (rat) or KIM-1 (human). The urinary Kim-1 band intensity using the rat Kim-1 dipstick significantly correlated with levels of Kim-1 as measured by a microbead-based assay, histopathological damage, and immunohistochemical assessment of renal Kim-1 in a dose- and time-dependent manner. Kim-1 was detected following kidney injury induced in rats by cadmium, gentamicin, or bilateral renal ischemia/reperfusion. In humans, the urinary KIM-1 band intensity was significantly greater in urine from patients with acute kidney injury than in urine from healthy volunteers. The KIM-1 dipstick also enabled temporal evaluation of kidney injury and recovery in two patients who developed postoperative acute kidney injury following cytoreductive surgery for malignant mesothelioma with intraoperative local cisplatin administration. We hope that future, more extensive studies will confirm the utility of these results, which show that the Kim-1/KIM-1 dipsticks can provide a sensitive and accurate detection of Kim-1/KIM-1, thereby providing a rapid diagnostic assay for kidney damage and facilitating the rapid and early detection of kidney injury in preclinical and clinical studies.

A rapid lateral flow immunoassay for identity testing of biotherapeutics.

Identity testing of biopharmaceutical products is conducted at multiple steps in the manufacturing process, for drug product lot release, and often for product importation. Because of the chemical and structural similarities of antibody-based products, they present a unique challenge for the development of a QC friendly identity assay where specificity is the critical attribute. Here we report on the development of a novel, rapid and highly specific assay designed to simplify identity testing of antibody-based biopharmaceutical products. A lateral flow immunoassay platform (LFIA) was optimized and used to develop seven identity-specific tests against therapeutic monoclonal antibodies. The specificity of each assay was verified against 10-40 antibody products. An average linear range of antibody detection from 50 to 10,000 ng/ml was observed, allowing minimal sample dilution to be performed. The optimized LFIA platform consistently produced a strong visual signal and showed no false positive results. Three of the seven LFIA-based identity assays have been successfully validated for product release, in accordance with ICH validation guidelines. Additional tests will be validated as products reach the commercial phase. We demonstrate that a lateral flow-based identity assay is an ideal analytical tool for identity testing of antibody therapeutics. The assay platform can easily be adapted for new antibody products and it can be quickly transferred and validated for product testing.

Novel assays for detection of urinary KIM-1 in mouse models of kidney injury.

Kidney injury molecule-1 (KIM-1) has been qualified by the Food and Drug Administration and European Medicines Agency as a urinary biomarker to monitor preclinical nephrotoxicity in rats and on a case-by-case basis for the translation of potentially nephrotoxic drugs into first-in human studies. Although mouse models are widely employed in preclinical studies, few urinary biomarker studies have been performed in mice due to limited urine availability and lack of sensitive assays. Here, we report the development and validation of two different assays for quantitative assessment of mouse urinary KIM-1 (uKIM-1) and compare the sensitivity of KIM-1 relative to other standard markers in ischemia reperfusion and aristolochic acid (AA)-induced kidney injury in mice. A sensitive, reproducible, and quantitative microbead-based KIM-1 ELISA was established, which requires only 10 µl urine for triplicate determination with an assay range of 12.21 pg/ml to 50 ng/ml. The second assay is a laminar flow dipstick assay, which has an assay range of 195 pg/ml to 50 ng/ml and provides quantitative assessment of KIM-1 in 15 min. uKIM-1 levels increased with increasing time of ischemia or time after AA administration. After only 10-min ischemia followed by 24-h reperfusion, uKIM-1 was significantly elevated by 13-fold, whereas serum creatinine (sCr), blood urea nitrogen, N-acetyl-ß-glucosaminidase (NAG), and proteinuria levels did not change. After AA administration, uKIM-1 levels were significantly upregulated by greater than threefold within 12 h, whereas sCr and NAG levels were unchanged. Mouse KIM-1 was stable for multiple freeze-thaw cycles, for up to 5 days at room temperature and up to at least an year when stored at -80°C.