Aptose Biosciences Inc. decided to temporarily delay all clinical activities pertaining to its product candidate APTO-253 in order to prioritize its resources to develop CG'806.

APTO-253 is a phase 1 stage compound for acute myeloid leukemia. CG'806 is a preclinical-stage compound being developed for FLT3-driven acute myeloid leukemia and certain BTK-driven B-cell malignancies.

The company made the decision to elucidate the cause of recent manufacturing setbacks related to the intravenous formulation of APTO-253. It plans to restore the molecule to a state supporting clinical development and partnering.

Aptose said its existing resources can support the full development activities of only one cancer drug at this time.

The FDA placed Aptose's phase 1b trial of APTO-253 in patients with acute myeloid leukemia on clinical hold in November 2015.