GSK3494245 (DDD01305143) is a potent, orally active, and selective inhibitor of the chymotrypsin-like activity of the parasite proteasome binding in a site sandwiched between the β4 and β5 subunits ( IC 50 =0.16 μM for WT L. donovani proteasomes). GSK3494245 moderately inhibits chymotrypsin-like activity of human proteasome (IC 50 : purified 26S=13 µM; enriched THP-1 extracts IC 50 =40µM). GSK3494245 exhibits attractive biological and biosafety properties. In Vitro GSK3494245 shows EC 50 value of 5.7 μM in L. donovani intramacrophage assay, where the amastigotes are cultured in differentiated THP-1 cells. GSK3494245 demonstrates good selectivity over mammalian cell growth inhibition (THP-1 cells; EC 50 > 50 μM). GSK3494245 (DDD01305143) shows pEC 50 s of 6.5 and 5.8 against axenic amastigote and ld InMac, respectively. Ld InMac is the intramacrophage assay carried out in THP-1 cells with L. donovani amastigote. MCE has not independently confirmed the accuracy of these methods. They are for reference only. In Vivo GSK3494245 (25 mg/kg; orally twice a day for 10 consecutive days) elicits a >95% reduction of parasite load in Infected mice ( L. donovani , LV9) . MCE has not independently confirmed the accuracy of these methods. They are for reference only. Form:Solid