OBJECTIVES: To compare price changes with time for oncology drugs from the USA, Israel and UK and to understand how different regulatory mechanisms influence price trajectories. METHODS: We analyzed historical prices of 17 patented cancer drugs that gained their initial FDA approval between 1997 and 2012. We included only drugs that were registered in the USA, UK and Israel. For US prices we used Average Sales Prices which are a baseline indicator for Medicare reimbursement. For Israel we used the Maximum Retail Prices, regulated by the Ministry of Health. For the UK we used list prices as published in the British National Formulary which represent the price arising from negotiation on a 5-year cycle. We presented all prices in US$ and also adjusted for inflation rates. For each drug we calculated the annual and cumulative price changes and compared trajectories between countries. RESULTS: Average cumulative changes in prices were +38% for the USA, -15% for the UK and -27% for Israel. Average quarterly changes were +1% in the US, -1% in the UK and -1.5% in Israel. Notable differences were observed for rituximab (US +79%, UK -28%, IL -39%) and trastuzumab (US +73%, UK -28%, IL -38%). For all drugs, except aflibercept, price trajectories showed increases with time in the USA. All drugs showed decreases with time in the UK and Israel. CONCLUSIONS: There are significant differences in cancer drug price trajectories between the USA, UK and Israel. Different countries and payers implement different regulatory mechanisms. While the Medicare is not legally permitted to negotiate prices in the USA, in other countries prices are negotiated prior to public reimbursement. Without regulation, prices will likely continue to rise in the USA as there is an inelastic demand for cancer treatments.