Key Takeaways:
- The ONCO PE trial demonstrated that an 18-month treatment with rivaroxaban significantly reduced recurrent venous thromboembolism (VTE) compared to a 6-month treatment in patients with cancer and acute low-risk pulmonary embolism (PE) (5.6% vs. 19.1%; OR, 0.25; 95% CI, 0.09–0.72; P=0.01).
- There was no statistically significant increase in major bleeding events with the longer rivaroxaban treatment (7.8% vs. 5.6%; OR, 1.43; 95% CI, 0.44–4.70; P=0.55).
- The study highlights the benefits of extended anticoagulation in preventing thrombotic events in this patient population, though individual bleeding risks must be considered.
Patients with cancer are at heightened risk of VTE, including pulmonary embolism (PE), a major complication during cancer treatment. Although international guidelines recommend extended anticoagulation therapy for cancer-associated PE, the optimal duration of therapy remains unclear, particularly in those with acute low-risk PE. The ONCO PE trial (ClinicalTrials.gov number, NCT04724460) investigated the efficacy and safety of 18-month versus 6-month rivaroxaban therapy in preventing recurrent VTE in this population.
The ONCO PE trial was a multicenter, open-label, adjudicator-blinded randomized trial conducted at 32 institutions in Japan. The results of the trial were presented at the AHA Scientific Sessions 2024 and simultaneously published in Circulation. ONCO PE enrolled 178 patients with active cancer and acute low-risk PE, defined by a simplified Pulmonary Embolism Severity Index (sPESI) score of 1. Participants were randomized 1:1 to receive rivaroxaban for either 18 months or 6 months. The primary endpoint was recurrent VTE at 18 months, and the secondary endpoint was major bleeding, evaluated per the International Society on Thrombosis and Haemostasis criteria.
The primary endpoint of recurrent VTE occurred in 5 patients (5.6%) in the 18-month group compared to 17 patients (19.1%) in the 6-month group (OR, 0.25; 95% CI, 0.09–0.72; P=0.01). Recurrent events included symptomatic and incidental PEs, as well as deep vein thrombosis. The major secondary endpoint, major bleeding, occurred in 7 patients (7.8%) in the 18-month group versus 5 patients (5.6%) in the 6-month group (OR, 1.43; 95% CI, 0.44–4.70; P=0.55). Notably, the most common bleeding site was the gastrointestinal tract. Other outcomes included death from all causes, which occurred in 32.6% of patients in the 18-month group compared to 25.8% in the 6-month group, though these differences were not statistically significant. Symptomatic VTE recurrence was lower in the 18-month group (1.1% vs. 4.5%; OR, 0.24; 95% CI, 0.03–2.20).
The findings of the ONCO PE trial highlight the potential of extended rivaroxaban therapy for patients with cancer and low-risk PE, though individual patient risks should guide therapy decisions. Further research may refine these strategies in broader cancer populations.