[CAS NO. 1446321-46-5]  Voxelotor (GBT440)

GBT440 has favorable oral bioavailability of 60, 37, and 36% in rats, dogs, and monkeys, respectively, with similar blood and plasma half-lives of approximately 20 h each. T1/2 value of GBT440 in all animal species is significantly shorter than the T1/2 of red blood cells (∼20 days), which supports that binding of GBT440 to hemoglobin is a reversible process. GBT440 is currently in Phase 3 clinical trials (NCT03036813) in SCD patients. GBT440 increases haemoglobin oxygen affinity, reduces sickling and prolongs RBC half-life in a murine model of sickle cell disease. In a murine model of SCD, GBT440 extends the half-life of RBCs, reduces reticulocyte counts and prevents ex vivo RBC sickling. Importantly, oral dosing of GBT440 in animals demonstrates suitability for once daily dosing in humans and a highly selective partitioning into RBCs, which is a key therapeutic safety attribute. GBT440 shows dose proportional PK, a terminal half-life of 1.5-3 d.