SAN DIEGO – Prophylaxis with rivaroxaban significantly reduced the rate of venous thromboembolism and associated death in high-risk ambulatory cancer patients receiving systemic therapy, results of a randomized trial show.
The reduction in venous thromboembolism (VTE) or VTE-related death was not statistically significant in the primary analysis, in part because a large proportion of patients stopped taking the direct oral anticoagulant, according to investigator Alok A. Khorana, MD, of the Cleveland Clinic.
However, the reduction in events was significant in a prespecified secondary analysis limited to the on-treatment period, Dr. Khorana reported at the annual meeting of the American Society of Hematology, adding that rates of major and nonmajor bleeding were low.
Results are “eagerly awaited” from a different prophylaxis trial – the AVERT study – looking at another direct oral anticoagulant in high-risk cancer patients, Dr. Khorana said in a late-breaking abstracts session.
“If the findings of that trial are consistent with ours, then we certainly hope that these findings should inform future recommendations regarding thromboprophylaxis for high-risk ambulatory cancer patients, and then the landscape of anticoagulation in the cancer population should start to shift from management of events to primary prevention,” he said.
In the study by Dr. Khorana and his colleagues, known as CASSINI, 841 patients with various solid tumors and lymphomas were randomized to either rivaroxaban 10 mg or placebo once daily. The patients, enrolled at 143 study centers in 11 countries, all had a Khorana risk score of 2 or greater.
In the primary analysis period of 180 days, the composite endpoint of VTE or VTE-related death occurred in 5.95% of the rivaroxaban-treated group and 8.79% of the placebo group (hazard ratio, 0.66; 95% confidence interval, 0.40-1.09; P = .101). However, a total of 177 patients (43.7%) stopped rivaroxaban earlier than 180 days, and likewise, 203 patients (50.2%) stopped placebo early.
In a prespecified secondary analysis looking just at the period of time when patients were actually taking rivaroxaban or placebo, rivaroxaban did significantly reduce risk of VTE or VTE-related death, Dr. Khorana said. The composite endpoint occurred in 2.62% of the rivaroxaban patients and 6.41% of placebo patients in that on-treatment analysis (HR, 0.40; 95% CI, 0.20-0.80; P = .007).
Rates of major bleeding and clinically relevant nonmajor bleeding were not significantly different between groups, according to results of a safety analysis. Major bleeding occurred in eight rivaroxaban patients and four placebo patients, or 1.98% and 0.99%, respectively (P = .265).
CASSINI was sponsored by Bayer and Janssen. Dr. Khorana reported disclosures related to Janssen, Bayer, PAREXEL, Sanofi, Pfizer, TriSalus Life Sciences, Halozyme, Seattle Genetics, AngioDynamics, and others.