OBJECTIVES: The cost of treating cancer has risen to unprecedented levels, putting tremendous financial pressure on patients, payers, and society.  Prior studies have documented the rising prices of cancer drugs at market entry, but less attention has been paid to trends in prices after market entry. The objective of this study was to examine post-entry trends in expenditures for recently FDA-approved orally administered anticancer drugs.   METHODS: We measured patient and health plan expenditures for a 30-day supply of recently FDA-approved orally administered anticancer drugs using pharmacy claims from Truven Health Analytics MarketScan Databases.  We used fixed-effects regression with time-varying covariates to explore whether changes in average expenditures for each drug measured quarterly were associated with receipt of a supplemental indication or introduction of a competitor. Expenditures were adjusted to 2014 USD using the consumer price index. RESULTS: Between 2007 and 2013, expenditures for a 30-day supply of each drug grew 5.2% (95% CI: 4.6%, 5.8%) per year. After adjusting for these trends, we found that expenditures for each drug did not change significantly in the quarter in which a new indication was approved; however, they rose significantly faster in subsequent quarters (expenditures rose 1.7% [95% CI: 0.6%, 2.7%] faster per year after FDA-approval of each supplemental indication).  In contrast, expenditures declined immediately when a competitor entered the market (declining 7.9% [95% CI: 5.7%, 10.1%] in the same quarter a competitor was introduced); however, this decline was followed by a significantly faster increase over time that negated the initial decline within two years. CONCLUSIONS: Our findings suggest there is currently little competitive pressure on oral chemotherapy costs after market entry. Further work is needed to understand how evidence regarding clinical benefits for newer oral chemotherapy agents changes over time, both within and across indications, and whether these changes are associated with the spending trends we observed.