The MURANO study (NCT02005471) is a Phase III trial looking at rituximab in combination with either bendamustine or venetoclax for the treatment of refractory chronic lymphocytic Leukemia (CLL). A key aim of the study is to assess whether mutated TP53 clone size affects treatment efficacy. Here, Arnon Kater, PhD, of Universiteit Van Amsterdam, Amsterdam, Netherlands, describes the interesting early results from a side study of the MURANO trial. Speaking from the 23rd Congress of the European Hematology Association (EHA) 2018, held in Stockholm, Sweden, Prof. Kater mentions that further results are needed to draw conclusions, and should be released at the end of the year.