In the United Kingdom, ibrutinib is funded as standard of care at first relapse for mantle cell lymphoma (MCL). Simon Rule, MD, Plymouth University, Plymouth, UK, discusses a study that analyzed the clinical effectiveness and tolerability of ibrutinib at first relapse in a non-clinical trial real-world population. Results indicate that response rates and the proportion of patients stopping ibrutinib due to toxicity were similar to trial data. This interview took place at the American Society of Hematology (ASH) 2019 Annual Meeting and Exposition in Orlando, FL.