Umbralisib: First Approval.

Umbralisib (UKONIQ™) is an oral, first-in-class dual phosphatidylinositol 3-kinase delta (PI3Kδ) and casein kinase 1 epsilon (CK1ε) inhibitor being developed by TG Therapeutics for the treatment of various haematological malignancies. In February 2021, umbralisib received its first approval in the USA for the treatment of adults with relapsed or refractory marginal zone lymphoma (MZL) who have received ≥ 1 prior anti-CD20-based regimen, and relapsed or refractory follicular lymphoma (FL) who have received ≥ 3 prior lines of systemic therapy. Clinical studies in various haematological malignancies, including chronic lymphocytic leukaemia and non-Hodgkin's lymphoma, are underway in multiple countries. This article summarizes the milestones in the development of umbralisib leading to this first approval.