(S)-ML753286 is a breast cancer resistance protein (BCRP) inhibitor with an IC50 of 0.6 μM on BCRP efflux transporter.IC50 & Target: IC50: 0.6 μM (BCRP efflux transporter)In Vivo: (S)-ML753286 (Compound A) shows the potency and a potent pharmacokinetic (PK) profile in rats (lower clearance [1.54 L/h/kg] and higher bioavailability [123%]). XL388 has moderate terminal elimination half-life with t1/2s of 0.9 h and 2.0 h for 2 mg/kg (iv) and 20 mg/kg (po) in rats, respectively.