API-CAT Trial Reveals Low-Dose Apixaban Prevents VTE in Cancer Patients

Low-Dose Apixaban Proves Effective for Long-Term Use in Cancer Patients, Reducing Risk of Venous Thromboembolism

A new study, the API-CAT trial, has brought forward some exciting news for cancer patients battling venous thromboembolism (VTE). For years, patients with active cancer have faced the dual challenge of managing their cancer treatment while simultaneously preventing blood clots, a common complication that can increase the risk of death. The latest findings from the API-CAT trial suggest that using a reduced dose of apixaban for long-term VTE prevention in cancer patients is just as effective as the higher dose and comes with the added benefit of a lower risk of clinically relevant bleeding.

These results, presented at the 2025 American College of Cardiology (ACC) Scientific Session and published in the New England Journal of Medicine, offer hope for a safer, more manageable option for cancer patients requiring extended anticoagulation therapy.

The Problem: VTE in Cancer Patients

Venous thromboembolism is a significant concern for cancer patients. In fact, VTE is the second-leading cause of death in cancer patients after cancer itself, and its prevalence continues to rise, especially as cancer treatments advance and patients live longer. VTE is commonly associated with both active cancer and cancer treatment, which makes it a major area of concern for oncologists and cardiologists alike.

As patients live longer, they are at a heightened risk of developing recurrent VTE, making anticoagulation therapy a cornerstone of post-treatment care. Traditionally, anticoagulation treatment continues for as long as the cancer is active, but what is the optimal dosage beyond the initial six-month period? This is where the new research comes in.

The API-CAT Trial: A Groundbreaking Study

The API-CAT trial sought to answer this critical question: Is there an optimal dose of apixaban for long-term VTE prophylaxis in cancer patients? The study involved 1,766 patients from 11 countries with active cancer, with the majority of participants (65.8%) having metastatic cancer. The patients, who had all experienced a proximal deep vein thrombosis (DVT) or pulmonary embolism, had completed at least six months of initial anticoagulant therapy and were then randomized to receive either a reduced dose (2.5 mg) or a full dose (5.0 mg) of apixaban twice daily for 12 months.

The primary outcome was to determine whether the reduced dose of apixaban was non-inferior to the full dose in preventing recurrent VTE. The results were striking:

• Recurrent VTE occurred in 18 patients (2.1%) in the reduced-dose group and 24 patients (2.8%) in the full-dose group. The difference was significant for non-inferiority, with an adjusted subhazard ratio of 0.76 (95% CI, 0.41–1.41).
• Clinically relevant bleeding occurred less frequently in the reduced-dose group (12.1%) compared to the full-dose group (15.6%), with an adjusted subhazard ratio of 0.75 (95% CI, 0.58–0.97; P = 0.03).

These findings suggest that a lower dose of apixaban is just as effective as the full dose in preventing recurrent VTE, but with a significantly lower risk of clinically relevant bleeding. Importantly, the mortality rate between the two groups was similar, indicating no compromise on patient survival.

Why This Matters: Changing Clinical Practice

The results of the API-CAT trial have the potential to revolutionize the way cancer patients are managed long-term when it comes to anticoagulation therapy. Lead investigator Isabelle Mahé, MD, PhD, from Université Paris Cité in France, emphasized that these findings could change clinical practice and guidelines. "We think these findings will result in a change in guidelines and clinical practice," said Dr. Mahé, during her presentation at the ACC Scientific Session.

This study is the first large-scale, randomized controlled trial to investigate the appropriate dose of anticoagulants for long-term VTE prophylaxis in cancer patients, and the results are promising. For oncologists and cardiologists, the ability to prescribe a reduced dose of apixaban could help mitigate the risk of bleeding while still providing effective protection against VTE recurrence. The reduced bleeding risk, in particular, could be crucial for patients who are undergoing chemotherapy or other treatments that already increase their bleeding risk.

The Broader Impact: Addressing a Growing Concern

The impact of the API-CAT trial extends far beyond individual patients. In the United States alone, there are 2 million new cancer diagnoses each year, with 20 million cancer survivors. Many of these patients face a high risk of thrombotic events, and the risk of bleeding with full-dose anticoagulants can be a significant concern. The study highlights the importance of addressing the bleeding risks in this population, where the balance between preventing clots and avoiding bleeding is particularly delicate.

Diego Sadler, MD, head of the cardio-oncology section at Cleveland Clinic Florida, emphasized the significance of the findings: "We can use a lower dose of anticoagulant and offer safe and effective prophylactic treatment. This is excellent news for cardiologists and oncologists," he said. The results also hold substantial implications for the growing number of cancer survivors who may require ongoing anticoagulation therapy.

Moving Forward: A New Standard of Care?

The API-CAT trial provides compelling evidence that lower-dose apixaban could be a safer, equally effective option for long-term VTE prevention in cancer patients. As Dr. Mahé pointed out, "We can say that lower-dose apixaban is both effective and safer than the full dose." However, the study also leaves room for further exploration. Experts like Bonnie Ky, MD, professor of cardio-oncology at the University of Pennsylvania, highlighted that while the study is groundbreaking, it raises important questions about the underlying mechanisms and clinical considerations that led to the lower dose being more effective at preventing VTE.

As the trial findings begin to shape clinical guidelines, it is crucial for clinicians to engage in open discussions with their patients about the potential risks and benefits of anticoagulation therapy. Patients, especially those with advanced cancer, should be well-informed and involved in the decision-making process, balancing the need for clot prevention with the potential risks associated with long-term anticoagulation.

Conclusion: A New Hope for Cancer Patients

The findings from the API-CAT trial could mark a significant shift in the management of cancer patients at risk for venous thromboembolism. By reducing the dose of apixaban, clinicians may be able to offer safer and equally effective prophylaxis for recurrent VTE, improving quality of life and reducing the risk of bleeding complications. As we look ahead, the results from this trial offer hope for better, more personalized care for cancer patients.