John Seymour, MD, MPH from the Peter MacCallum Cancer Center, Melbourne, Australia, discusses predictive markers for chronic lymphocytic leukemia (CLL) that may help in identifying optimally effective treatment regimens for individual patients. These include the 17p deletion and complex karyotype in some CLL patients, which affect their responses to ibrutinib and venetoclax. He notes that data on these predictors are unclear as there have not yet been any randomised trials comparing one novel therapy to another. This video was recorded at the International Workshop on Chronic Lymphocytic Leukemia (iwCLL) 2017 in New York, NY.