Clinical outcomes of venous thromboembolism with dalteparin therapy in multiple myeloma patients

This study focused on the clinical outcomes in multiple myeloma (MM) patients with venous thromboembolism (VTE) who received low-molecular-weight heparin (dalteparin) therapy. Changes in D-dimer levels before and after VTE were also evaluated. Among 549 patients treated with various chemotherapeutic agents, a total of 52 (9.47%) patients including 32 newly diagnosed with MM and 16 with relapsed/refractory MM developed VTE, 48 of whom received dalteparin. Among the 48 treated patients, 37 (77%) had proximal deep vein thrombosis (DVT), four had (8%) pulmonary embolism (PE), and seven (15%) had both DVT and PE. In 32 patients with available paired samples (at baseline and VTE occurrence), significant conversion of D-dimer levels from 2.2 ± 0.4 mg/L to 11.8 ± 1.6 mg/L (P < 0.001) was observed, which decreased from 10.9 ± 0.4 mg/L to 1.9 ± 0.6 mg/L one month after initiating dalteparin therapy. A total of 44 patients received dalteparin with a median duration of 4.2 months (range, 2.7-9.4), and four patients were discontinued early due to death (n = 3) and major bleeding (n = 1). After a median follow-up of 9.0 months (range, 0.7-35.8) since the first VTE episode, five patients showed recurrence of VTE with a cumulative incidence of 17.5 ± 7.9%. Major bleeding occurred in three patients. In summary, dalteparin seems to be a promising drug for the treatment of VTE in MM. In addition, the significant difference in D-dimer levels observed before occurrence of VTE and after dalteparin treatment may suggest the usefulness of D-dimer testing as a surrogate marker for VTE in MM patients.