Ibrutinib dose intensity and clinical outcomes. (A) Ibrutinib dose intensity of 84 CLL patients on study. Arrows indicate subgroups defined by dose intensity (%). The darkest blue shade indicates 7 patients who had <80% dose intensity; the intermediate blue shade indicates those with <90% dose intensity; the lightest shade indicates those with <95% dose intensity. Patients receiving full-dose ibrutinib (420 mg per day) are represented by black circles; red circles indicate patients who had permanent dose reductions to 280 mg per day; purple triangles indicate reductions to 140 mg per day. (B) Summary of the study cohort and subgroups divided by dose intensity. (C-F) Landmark analysis of PFS (C,E) and OS (D,F) of subgroups divided by ibrutinib interruption of any duration within the first 6 months (C,D) or 1 year (E,F) of starting ibrutinib. The number at risk for 6-month dose adherence was 79 for PFS and 80 for OS, with an additional patient who progressed and was alive at 6 months included in the OS analysis. The numbers at risk for 1-year dose adherence were 76 and 77 for PFS and OS, respectively. (G) A landmark analysis of PFS of subgroups divided by 8-week dose intensity (DI_8-week) above vs at or below mean of the cohort. *The most common reasons for dose interruption were elective procedures (ie, Mohs surgery, ophthalmologic procedures, arthroscopy or intraarticular injections, dental procedures) followed by toxicity and noncompliance. **The most common reason for permanent dose reduction was atrial fibrillation (41.7%) followed by arthralgia (25%) and diarrhea (16.7%). IQR, interquartile range; SD, standard deviation.