New oral anticoagulants in patients with cancer: current state of evidence

Effectiveness of new oral anticoagulants (NOAC) in patients with cancer is not clearly defined. There remain concerns of doubtful benefit and chances of potential harm with newer agents. In this meta-analysis, we evaluated the efficacy and safety of NOAC in patients with cancer. PubMed, Cochrane Library, EMBASE, Web of Science, and CINAHL databases were searched from January 01, 2001 through February 28, 2013. Randomized controlled trials reporting efficacy and safety data of NOACs (rivaroxaban, dabigatran, and apixaban) with control (low-molecular-weight heparin/vitamin K antagonists/placebo) for patients with cancer were included. Primary efficacy outcome was venous thromboembolism (VTE) or VTE-related death, and primary safety outcome was clinically relevant bleeding. We used random-effects models. Six trials randomized 19,832 patients, and 1197 patients had cancer. Risk of VTE or VTE-related death was not significantly different with NOAC versus control [odds ratio (OR), 0.80; 95% confidence interval (CI), 0.39-1.65] in patients with cancer. Separate analysis for individual effects showed similar results for rivaroxaban (OR, 1.08; 95% CI, 0.60-1.94) and dabigatran (OR, 0.91; 95% CI, 0.21-3.91). Clinically relevant bleeding was not higher with NOAC compared with control (OR, 1.49; 95% CI, 0.82-2.71); individual effect of rivaroxaban showed similar results. No statistically significant difference of efficacy and safety with NOAC was found between patients with and without cancer. Rivaroxaban might be equally effective and safe as vitamin K antagonist in patients with cancer. Dabigatran is as effective as comparator; however, safety profile of dabigatran is unknown. Randomized trials of new anticoagulants specific to the cancer population are necessary, and NOAC also need to be evaluated against low-molecular-weight heparin.