Data monitoring committees (DMCs) play a critical role in protecting the safety of participants and integrity of clinical studies. While there are well-established DMC guidelines for traditional, randomized controlled trials, the clinical trial community is still in the search for best practices in data and safety monitoring in pragmatic clinical trials. ADAPTABLE was a large, open label, pragmatic, randomized controlled trial, harnessing real world data from multiple sources and studying the comparative effectiveness of the two most common dosages of aspirin in patients with atherosclerotic cardiovascular disease. Specific issues arose in ADAPTABLE such as data quality, information latency, and protocol adherence, and these issues were both expected and unexpected features of the pragmatic study design. These issues imposed great challenges to the DMC members who were tasked to make critical decisions during the study. This article summarizes the unique experience of the ADAPTABLE DMC, including the internal debates and concerns, the concerted efforts to accomplish its mission, and the special contribution of the patient representatives. We also offer recommendations on data and safety monitoring for future pragmatic trials.