Chapter 1 reports on the U.S. drug supply and the complex way it is interwoven with multiple stakeholders involved in each step of the process. When investigational drugs show promise for treating serious or life-threatening diseases, patients are often interested in obtaining access to them. Congress included a provision in the FDA Reauthorization Act of 2017 for GAO to review actions taken to facilitate access to these drugs. Chapter 2 describes (1) actions FDA and drug manufacturers have taken to broaden eligibility criteria for clinical trials, (2) actions FDA has taken to facilitate access to investigational drugs outside of clinical trials, and (3) information drug manufacturers have communicated to patients and physicians about access to investigational drugs outside of clinical trials. Chapter 3 reports on requiring e-prescriptions for coverage under part D of the Medicare program for prescription drugs that are controlled substances.