XK-469 (NSC 697887) is a synthetic quinoxaline phenoxypropionic acid derivative that possesses unusual solid tumor selectivity and activity against multidrug-resistant cancer cells. XK469 acts as a selective topoisomerase IIβ inhibitor. Other proposed mechanisms include XK469-induced inhibition of cyclin B1 ubiquitination and apoptosis via binding of the peripheral benzodiazepine receptor. A phase I study was performed to determine the safety and pharmacokinetics of XK469R in patients with various neoplasms.

L-Gulonic acid, a diastereomer of d-gluconic acid is the one of a metabolite in the urinate cycle, is a substrate of L-Gulonate 3-dehydrogenase (GDH). This enzyme catalyzes the NAD(+)-linked dehydrogenation of L-gulonate into dehydro-L-gulonate. L-Gulonic acid is also a metabolite of the D-glucuronic acid pathway. It was suggested, that the measurement of a spectrum of urinary D-glucuronic acid metabolites might provide a more reliable index for assessment of the induction of hepatic xenobiotic-metabolizing enzyme activities in man than the determination of urinary D-glucaric acid alone.