Access to anti-cancer drugs for off-label purposes-or the use of drugs for cancer indications that are not approved by the FDA-is considered vital to the treatment of many cancer patients. However, recent literature on off-label use of oncology drugs has mostly focused on describing utilization patterns but pays very little attention to federal and state policies that may influence off-label use; furthermore, it has been infrequently noted that patients with ready access to off-label drugs through their insurance may have fewer incentives to enroll in clinical trials that provide valuable evidence about drugs in new indications. Dr. Smieliauskas proposes to estimate the effects on off-label drug utilization of two types of changes in health insurance coverage policies: state health insurance mandates that force private health insurance plans to cover off-label oncology drug use, and a 2008 rule change mandating that Medicare cover a larger number of off-label use of drugs on enrollment and the initiation and timely completion of clinical trials for drugs in those uses, as well as conduct exploratory research into the effects of this drug use on patient survival and morbidity. This will provide a series of evidence on the effects, both intended and unintended, of off-label drug use policies on cancer care and research.