Multiple myeloma patients have a higher risk of vascular thromboembolic events (VTEs). For a post hoc analysis, researchers assessed VTEs in phase 2 randomized GRIFFIN trial, which examined lenalidomide/bortezomib/dexamethasone (RVd) ± daratumumab(D). 

Patients who met the criteria for autologous stem cell transplantation (ASCT) and had recently been diagnosed with multiple myeloma underwent D-RVd/RVd induction, high-dose treatment, ASCT, D-RVd/RVd consolidation, and up to 2 years of lenalidomide maintenance therapy ± D. 

In agreement with the recommendations of the International Myeloma Working Group, VTE prevention (at least aspirin, ≥162 mg daily) was advised. Grade 2-4 VTEs occurred in 9.1% and 14.7% of the safety population (D-RVd, n = 99; RVd, n = 102), while VTEs occurred in 10.1% of D-RVd patients and 15.7% of RVd patients. D-RVd patients had a longer median time to the first sign of VTE than RVd patients (305 days vs. 119 days). In patients with VTEs, prophylaxis usage at the time of the first VTE onset was 60.0% for D-RVd and 68.8% for RVd. Anti-thrombosis prophylactic use was comparable between arms (D-RVd, 84.8% vs RVd, 83.3%). 

In conclusion, the incidence of VTEs was not increased by the addition of daratumumab to RVd, but the cumulative incidence of VTEs was high in the group, and the use of anti-thrombotic prophylaxis was not ideal.