And adding to the bleak picture of the class, TG Therapeutics' approved PI3K drug Ukoniq (umbralisib) has been placed on a clinical hold by the FDA while it investigates a safety signal.

Schematic of signalling through the phosphatidylinositol-3-kinase (PI3K)/AKT pathway. Class 1B PI3Ks consist of p110γ and a regulatory subunit, p101, and are activated directly by G-protein ...