e18016 Background: The use of targeted oral cancer medications has increased significantly since 2001. Everolimus, an mTOR inhibitor was first approved for cancer treatment by FDA as second line for patients with advanced renal cancer. Subsequently it has been approved for advanced pancreatic neuroendocrine tumor (NET) in 2011 and breast cancer in 2012 respectively. Off-label use is common in oncology practice. The objective of this study is to assess prescription trends, especially off-label use of everolimus, among non-elderly cancer patients with private insurance in the United States from 2009 to 2014. Methods: Data from the MarketScan database were analyzed. Between 2009 to 2014, 4,728 cancer patients with at least one everolimus prescription were included in the analyses. The diagnosis which incurred the most recently to the initial everolimus use in each calendar year was recorded. Off-label use was defined as using everolimus by all of the cancer types except of renal cancer in 2009-2014, NET in 2011-2014 and breast cancer in 2012-2014. Results: The number of patients received everolimus has increased significantly from 243 in 2009 to 1,194 in 2014. The most common diagnoses associated with everolimus use were breast cancer (42%), followed by renal cancer (24%), and NET (7%). Off-label use of everolimus increased from 29% in 2009 to 47% in 2011 then decreased to 23% in 2014. The 3 most common diagnoses associated with off-label use of everolimus were secondary malignancies (30.7%), breast cancer (10.4%) and liver cancer (5%) in 2009-2011, compared to secondary malignancies (47.3%), brain cancer (4.2%) and lung cancer (3.9%) in 2012-2014. The off-label use in female has decreased significantly from 32% in 2009 to 19% in 2014 (p = 0.03). There was no statistical difference in off-label use of everolimus by geographic region. Conclusions: Analyses of MarketScan data suggest off-label use of everolimus is common among US cancer patients, especially in lung, liver and brain cancer and secondary malignancies after the approved indication was expanded to breast cancer in 2012. Further research of the factors associated with off-label use of everolimus and its economic implication is needed.