Figure 1. Design of hybrids of ART and PIs and their efficacy in parasite clearance and recrudescence.

(A) Structures of ART analog ART1, PI01, and hybrid compounds.

(B) (Top) Dose-dependent inhibition of the proteasome activity and (bottom) inhibition of the Plasmodium parasite growth in red blood cells. Dd2β6^A117D and Dd2β5A48S are mutant strains resistant to PIs.

(C) In vivo efficacy of ATZ4 against P. berghei ANKA lux in mice. (Top) Scheme of the in vivo efficacy study with Swiss Webster mice (5 per treatment). P. berghei ANKA lux was injected in the tail vein on day 0. ATZ4 was administered interaperitoneally at 10, 25, or 50 mg/kg on day 3 to day 6 once daily for a total of four doses. Chloroquine was used as a positive control at 20 mg/kg intraperitoneally. Bioluminescence in each mouse was recorded on day 7. (Left) Luminescence images of mice in respective treatment groups. (Right) Quantification of parasite load in luminescence in each group in (left). The experiment was performed twice, and a representative is shown. Error bars represent standard deviations of the mean.

(D) In vivo efficacy of ATZ4 against recrudescence of P. berghei K13^R551T. (Top) Scheme of the modified Peters’ 4-day suppressive test.³⁵ Mice infected with Pb ART-resistant K13^R551T mutant were treated with vehicle, ART (50 mg/kg), ATZ4 (100 mg/kg), and deoxy-ATZ4 (100 mg/kg) administered via interaperitoneal injection 3 h after inoculation of parasites on day 0 and continued on day 1 and day 2 (shown by arrows). Parasitemia in each mouse was monitored by microscopic analysis of Giemsa-stained blood smears on days 6, 8, and 10. The rates of recrudescence in each cohort on the indicated days were plotted as the percentages of mice with a positive smear. Error bars represent standard deviations of the mean.