Animal experiment:

For in vivo PK studies, female CD-1 mice (25 to 30g) are used and randomly assigned to cages. Mice are allowed to acclimate before initiation of the experiments. Feed and water are given ad libitum. KDU691 is formulated at concentrations of 2.5 mg/mL and 0.25 mg/mL for a dose of 25 mg/kg and 2.5 mg/kg, respectively. The suspension formulation for p.o. dosing contains 0.5% Methyl cellulose and 0.5% Tween 80 in water. After oral dosing, blood and liver samples from mice are collected at 0.08 to 24 h post dosing. Groups of three mice are used for each time point. Blood is centrifuged at 13,000 rpm for 7 min at 4℃, plasma harvested and stored at -20℃ until analysis. Liver tissue samples are excised, dipped in PBS, gently blotted with absorbent paper, dried, weighed and stored at -20℃ until further analysis[1].

KDU691 is a PI4K inhibitor.

During the 5 days of dosing, no major weight changes are observed in the animals that receive KDU691 as prophylactic treatment (group 691-proph). From the fourth day of dosing, the animals that are treated with KDU691 show a transient yellow skin color. The KDU691 radical-cure group (group 691-RC) becomes blood-stage positive again at 31.8±0.5 days p.i. (range, 31 to 32 days). Clinical chemistry analysis of the group 691-RC monkeys reveals that bilirubin levels accumulate during the 5-day radical-cure treatment with KDU691[1].

[1]. Zeeman AM, et al. PI4 Kinase Is a Prophylactic but Not Radical Curative Target in Plasmodium vivax-Type Malaria Parasites. Antimicrob Agents Chemother. 2016 Apr 22;60(5):2858-63.