Relapse and failure of ibrutinib and idelalisib regimens in chronic lymphocytic leukaemia (CLL) is becoming an increasingly common. Here, Christopher Fox, MBChB(Hons), MRCP FRCPath, of Nottingham University Hospitals NHS Trust, Nottingham, UK, discusses the use of venetoclax for patients who have failed these BTK inhibitors. Venetoclax has proven effective in trials, with high efficacy, response rates, impressive progression-free survival and MRD negativity.