A series of fused bicyclic heteroaromatic derivatives of formula (IA) or (IB), as defined herein, being selective inhibitors of phosphatidylinositol-4-kinase IIIβ (PI4KIIIβ) activity, are beneficial in the treatment and/or prevention of various human ailments, including inflammatory, autoimmune and oncological disorders viral diseases and malaria and organ and cell transplant rejection.