Ambit's selectivity gambit

Ambit Biosciences Corp. is hoping to have the first FLT3 inhibitor that is sufficiently potent and selective to be used as a single agent in acute myelogenous leukemia. After seeing a good response rate early in a Phase I trial, the company modified the study to evaluate a continuous-dosing regimen of AC220 and hopes to jump straight into a pivotal study by the end of 1H09.

Ambit believes AC220's specificity for inhibiting FMS-like tyrosine kinase 3 (FLT3) is the key that allows it to be given as monotherapy in doses strong enough to produce durable responses in AML patients with FLT3 mutations...