In active cancer patients with low-risk PE and anemia, 18-month rivaroxaban reduced recurrent VTE incidence from 15.7% to 3.3% without increasing major bleeding.
Does 18-month rivaroxaban treatment reduce recurrent VTE compared to 6-month treatment in active cancer patients with low-risk pulmonary embolism, regardless of anemia status?
An 18-month rivaroxaban regimen reduces recurrent VTE compared to a 6-month regimen in active cancer patients with low-risk PE, without increasing major bleeding risk, even in patients with anemia.
Abstract Background/Introduction The ONCO PE trial has revealed superiority of 18-month rivaroxaban treatment for active cancer patients with low-risk pulmonary embolism (PE) of the simplified version of the Pulmonary Embolism Severity Index (sPESI) score of 1 in terms of the efficacy. However, there could be some concerns on an increased bleeding risk with prolonged anticoagulation therapy especially in patients with a high-bleeding risk including anemia. Thus, it has been still a matter of active debate whether the results of the ONCO PE trial could apply to patients with anemia. Purpose This pre-specified subgroup analysis aimed to compare the clinical outcomes of an 18-month compared to 6-month rivaroxaban treatment for active cancer patients with low-risk PE of the sPESI of 1 according to the presence or absence of anemia. Methods This subgroup analysis included a total of 178 patients, who were divided into anemia (N=118) and no-anemia (N=60) subgroups. Anemia was defined as hemoglobin 13 g/dL for men and 12 g/dL for women based on the World Health Organization definition. We evaluated 18-months clinical outcomes comparing 18-month and 6-month rivaroxaban treatment among subgroups. The primary endpoint was recurrent venous thromboembolism (VTE), and the major secondary endpoint was major bleeding. Other secondary endpoints were all-cause death, symptomatic recurrent VTE events, and all clinically relevant bleeding events. Results The mean hemoglobin levels were 10.3±1.3 g/dL in the anemia subgroup and 13.5±1.4 g/dL in the no-anemia subgroup, respectively. There were no differences in most aspects of patient characteristics between the anemia and no-anemia subgroups, whereas, the anemia subgroup had a lower body weight (59±11 vs. 62±12 kg, P=0.08), and was more frequently undergoing chemotherapy (70% vs. 42%, P=0.001). Among the anemia subgroup, the incidence of the primary endpoint was lower in the 18-month group (3.3% vs. 15.7%, Log-rank P=0.046), and there was no significant difference in the major secondary endpoint between 18-month and 6-month groups (8.3% vs. 7.8%, Log-rank P=0.99), which was fully consistent with the primary report (Figure 1). Among the no-anemia subgroup, there was no significant difference in the primary endpoint and the major secondary endpoint between 18-month and 6-month groups (15.0% vs. 30.3%, Log-rank P=0.24; 8.7% vs. 2.9%, Log-rank P=0.31) (Figure 2). Among both the anemia and no-anemia subgroups, there was no significant difference in the other secondary endpoints between 18-month and 6-month groups. Conclusions An 18-month rivaroxaban regimen for active cancer patients with low-risk PE was consistently superior to a 6-month rivaroxaban regimen across the presence of anemia for the thrombotic risk without an increase in the risk of bleeding with prolonged anticoagulation therapy, which suggested that there could be no concerns on the application of the results of ONCO PE trial for patients with anemia.
Chatani et al. (2025) studied this question. In active cancer patients with low-risk PE and anemia, 18-month rivaroxaban reduced recurrent VTE incidence from 15.7% to 3.3% without increasing major bleeding.