Clinical question: Is an oral direct factor Xa inhibitor an effective alternative to low-molecular-weight heparin (LMWH) in treating cancer related venous thromboembolism (VTE)?
Background: LMWH has been the standard of care for treatment in patients with VTE and cancer. A newer class of drug, the direct factor Xa inhibitors, have been shown to be noninferior to vitamin K antagonists (VKAs) in treatment of VTE in noncancer patients, but little is known about their use in patients with cancer.
Study Design: Randomized, open-label, multicenter pilot trial.
Setting: United Kingdom; patients were recruited through the Clinical Trials Unit at the University of Warwick, Coventry.
Dr. Ryan Marten
Synopsis: The authors randomly assigned 406 cancer patients with diagnosed VTE either to the LMWH group or to the oral direct factor Xa inhibitor group to evaluate the primary endpoint of VTE reoccurrence and secondary endpoints of major bleeding or clinically relevant but not major bleeding (CRNMB). Rivaroxaban was noninferior to dalteparin in preventing VTE reoccurrence, with a 6-month VTE reoccurrence rate for dalteparin of 11% (95% confidence interval, 7%-16%) and a reoccurrence rate of 6% for rivaroxaban (95% CI, 2%-9%). Rates of major bleeding events were similar, although patients with esophageal or gastroesophageal cancers tended to experience more major bleeds with rivaroxaban than with dalteparin (4 of 11 vs. 1 of 19). CRNMB was 4% for dalteparin and 13% for rivaroxaban (hazard ratio, 3.76; 95% CI, 1.64-8.69). Limitations include slow recruitment, high mortality rate, and the treatment length being only 6 months.
Bottom line: In this small study, rivaroxaban was equally effective at reducing the rate of reoccurrence of cancer related VTE at 6 months but had higher rates of CRNMB. Patients with GI cancers may be at higher risk for major GI bleeding with rivaroxaban.
Citation: Young AM et al. Comparison of an oral factor Xa inhibitor with low molecular weight heparin in patients with cancer with venous thromboembolism: Results of a randomized trial (SELECT-D). J Clin Oncol. 2018 Jul 10. 36(20):2017-23.
Dr. Marten is an assistant professor of medicine in the division of hospital medicine at Emory University, Atlanta.