The incidence of treatment-related thrombocytopenia in our study (12%) was lower than that reported in studies of other BET inhibitors (22–96%).28,31–34 Though it is difficult to make direct comparisons due to differences in patient populations, there were no DLTs due to thrombocytopenia with RO6870810, which also differs from other agents in this class.28,31–34 While we cannot exclude insufficient exposure or target coverage as a potential explanation, RO6870810 did achieve pharmacokinetic exposures that were associated with pharmacodynamic effects. This evidence concerns the gene DNER and Thrombocytopenia.