Background: Patients with newly diagnosed multiple myeloma is at increased risk of thrombotic events, primarily venous thrombosis. The risk is significantly increased in patients receiving certain therapeutic regimens such as the combination of thalidomide and dexamethasone. Deep vein thrombosis, especially if complicated by pulmonary embolism, can result in death. It is not clear if venous thrombotic events can result in compromised survival in this group of patients.

Methods: We studied patients enrolled in the Eastern Co-operative Group trial (E1A00) that randomized patients with newly diagnosed myeloma to single agent dexamethasone or thalidomide and dexamethasone. Patients with grade 3 or greater thrombotic events (DVT, or myocardial ischemia, or stroke) were identified. Wilcoxon rank sum test (for continuous variables) or Fisher’s exact test (for categorical variables) was used to compare age, baseline M-protein, hemoglobin, WBC, platelets count, creatinine, beta2-microglobulin, or ECOG PS between patients with and without thrombotic events.

Results: Among the 207 patients enrolled, 36 patients (17.4%) had grade 3 or greater thrombotic events with any treatment attribution, of whom, 27 patients had DVT, 3 patients had an MI and 6 pts had a stroke. However, in only 31 of these patients were the event considered treatment-related (possible, probable, or definite) and among these 24 had a DVT. The baseline characteristics did not differ between the patients with thrombosis and those without, irrespective of its relationship to treatment. Similarly, the baseline characteristics did not diff for those with venous or arterial thrombosis. The overall survival was similar among the patients developing a DVT compared to those without a thrombotic event, when all DVT events were considered irrespective of the treatment attribution (Figure). However, majority of the patients with an arterial event (3 patients with MI and 6 with stroke) had a short overall survival.

Conclusion: Venous thrombosis remains a common complication in patients with myeloma, especially when treated with thalidomide and dexamethasone. While occurrence of thrombosis clearly contributes to morbidity and often leads to dose reductions and missed doses, it does not appear to have an adverse impact on the overall survival of these patients.

Author notes

Disclosure:Research Funding: Celgene Corp provides funding for clinical trial.