The CASSINI trial set out to answer whether low-dose rivaroxaban was more effective than placebo in reducing the incidence of venous thromboembolic disease in ambulatory patients with cancer at high risk for thromboembolism [Khorana score (KS) ≥2]. The trial showed that rivaroxaban did not result in a statistically significant reduction in the incidence of venous thromboembolism (VTE) at 180 days when compared to placebo. However, in a pre-specified intervention-period (only time on drug considered), there was a 3.6% absolute reduction in VTE with rivaroxaban. Patients with higher KS are known to have higher risk of VTE and absolute risk/benefit of prophylaxis may change by risk score category. The aim of the current study by Dr. Alok Khorana and colleagues was to compare the efficacy of rivaroxaban prophylaxis in patients with KS ≥3 compared to those with KS=2 who had been enrolled in the CASSINI trial. The primary efficacy endpoint was a composite of lower-extremity proximal DVT, symptomatic upper/lower-extremity distal DVT, pulmonary embolism and VTE-related death, while the primary safety endpoint was major bleeding.
Dr Khorana states “In the placebo arm, patients with a KS ≥3 had higher rates of both primary endpoint events compared with KS=2 up to day 180 (10.6% vs 8.1% respectively) and all-cause mortality (30.9% vs 20.7%). Hazard ratios for primary endpoint reduction were similar, along with major bleeding rates. “The efficacy and safety of low-dose rivaroxaban in patients with KS ≥3 appear to be similar to the efficacy and safety of low-dose rivaroxaban in patients with KS 2. These findings support the conclusions drawn in out in the CASSINI trial in demonstrating net benefit of rivaroxaban prophylaxis in cancer patients with KS ≥2 while on treatment.”