Our study was designed to look at whether we can reduce thrombotic events in cancer patients. Cancer patients typically are very high risk for getting blood clots, like a deep vein thrombosis or a pulmonary embolism and you can identify that risk based on a formal risk assessment score. We used that risk score to identify high risk patients and then we randomised patients to either rivaroxaban, 10mg once daily, or placebo to see if using rivaroxaban would reduce the risk without increasing the risk of bleeding.
How many patients?
It was 841 patients that were randomised. It was a massive undertaking, it was eleven countries, 143 study centres worldwide, but we were able to randomise 841 patients. The study results, we were able to show that with rivaroxaban you could reduce the number of thrombotic events substantially but the real reduction occurred only during the time frame that patients were on treatment but not during the full study period. The reason for that was that about 40% of events in the study occurred in patients who had stopped taking the drug. That has implications for clinical practice – moving forward we really have to educate patients that they should stay on the drug for as long as feasible.
What is the take-home message?
The take-home message is that cancer patients at a high risk for getting thrombotic events, we can predict that risk pretty successfully using a validated risk score, we can take high risk cancer patients and give them a daily dose of rivaroxaban, 10mg once daily, and reduce the risk substantially as long as patients take the drug. We did not really have any safety concerns, major bleeding incidence was quite low and non-major bleeding incidence was also quite low. So we are reassured about safety.