In patients with active cancer who have been hospitalized for a venous thromboembolism (VTE) event, rivaroxaban (Xarelto; Bayer/Janssen) is as effective as apixaban (Eliquis; Bristol-Myers Squibb) in preventing recurrence over short-term follow-up, according to data from the OSCAR series of trials.
The study fits with recent evidence from a systematic review and meta-analysis that found that cancer patients are 40% less likely to experience recurrent acute VTE when treated with direct oral anticoagulants (DOACs)—including apixaban, rivaroxaban, and edoxaban (Savaysa; Daiichi Sankyo)—rather than low-molecular-weight heparin (LMWH).
While these randomized trials, including Caravaggio, have compared individual DOACs with LMWH for treatment of cancer-associated VTE, there are no published randomized, head-to-head data of DOACs. The COBRRA trial of apixaban versus rivaroxaban is ongoing.
“The trials fairly uniformly demonstrated that oral factor Xa inhibitors are at least as effective as low- molecular-weight heparin,” OSCAR senior investigator Craig I. Coleman, PharmD (University of Connecticut School of Pharmacy, Storrs), who presented the results at the recent American Society of Hematology meeting, told TCTMD.
Using de-identified electronic health data, Coleman and colleagues conducted a retrospective study of the time to first composite event of recurrent VTE or any bleeding resulting in hospitalization in adults with a variety of primary or metastatic cancers who received rivaroxaban or apixaban prophylaxis following a VTE event.
At 3 months, the rate of composite events was 5.3% in the rivaroxaban group and 6.0% in the apixaban group (HR 0.87; 95% CI 0.60-1.27). Patients included in the study had cancers that guidelines suggest are suitable for treatment with DOACs as opposed to the LMWH enoxaparin. Cancers that are not suitable for treatment with oral factor Xa inhibitors include esophageal, gastric, colorectal, bladder, noncerebral central nervous system cancers, and leukemias, Coleman noted.
More Data Needed on Specific Cancers
The study included 2,437 patients, most of whom were over age 40 and younger than age 75 (56.9% female), and had been admitted to a hospital, emergency department, or observation unit for a cancer-associated VTE event. In 45.6% of patients, the event was a pulmonary embolism and/or deep vein thrombosis (DVT).
The most common active or metastatic cancers included breast, lung, prostate, and hepatobiliary. Nearly 60% of patients had received treatment for an active cancer within 4 weeks of the cancer-associated thrombosis event. Apixaban was used in 1,344 patients and rivaroxaban in 1,093 patients beginning on day 7 after the VTE event. More than 60% of patients in each treatment group had hypertension, and approximately 10% in each group had a prior history of VTE.
At 6 months, rates of the composite outcome of recurrent VTE or any bleeding resulting in hospitalization were 7.5% in both the apixaban and rivaroxaban groups. No differences were seen between groups at that time point for recurrent VTE, bleeding-related hospitalization, critical organ bleed, or the composite of recurrent VTE or critical organ bleed.
Coleman said the findings suggest that “either is probably a reasonable choice for treating cancer associated thrombosis.” He added that the decision as to which agent to choose—once-daily rivaroxaban or twice-daily apixaban—should be based on consideration of patient preference and adherence considerations.
While on the whole the study suggests similar efficacy and safety for both DOACs across most cancers, Coleman said next steps will be to look more closely at how the drugs fared in individual cancer types. In the current study, the numbers of patients with specific cancers were too small to make those assessments. The real-world OSCAR program will continue to enroll patients, he added, which will grow the numbers of patients who can be assessed.
L.A. McKeown is a Senior Medical Journalist for TCTMD, the Section Editor of CV Team Forum, and Senior Medical…
Coleman CI. Rivaroxaban versus apixaban for treatment of cancer-associated venous thromboembolism: a head-to-head analysis of the United States cohort of the observational study in cancer-associated thrombosis for rivaroxaban (OSCAR-US-H2H). Presented at: American Society of Hematology. December 11, 2022.
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