Copanlisib is a novel PI3K inhibitor, targeting both PI3K-? and PI3K-? isoforms in malignant B-cells. It was granted FDA approval based on data from the Phase II CHRONOS-1 study (NCT01660451) investigating copanlisib in relapsed/refractory B-cell non-Hodgkin lymphoma (NHL). Here, George Follows, BMBCh, PhD, FRCP, FRCPath, of Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK, discusses the longer term follow-up data being presented at the American Society of Hematology (ASH) 2017 Annual Meeting and Exposition in Atlanta, GA.