A real-world evaluation of the effectiveness of dalteparin in the prevention of recurrent venous thromboembolism compared to warfarin in patients with cancer.

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9115 Background: The Randomized Comparison of Low-Molecular-Weight Heparin versus Oral Anticoagulant Therapy for the Prevention of Recurrent Venous Thromboembolism in Patients with Cancer (CLOT) study demonstrated better efficacy of dalteparin, a low-molecular-weight- heparin (LMWH), compared to warfarin in prevention of recurrent venous thromboembolism (VTE) events in cancer patients. The purpose of the current study was to evaluate the effectiveness of dalteparin in real-world practice against warfarin as evaluated in the CLOT study. Methods: Commercial claims data from January 1, 2004 to December 31, 2008 was used in this retrospective analysis. The study population was identified as follows: cancer patients (ICD-9-CM codes 140.xx–239.xx) with a diagnosis of VTE including deep vein thrombosis (DVT) (ICD-9- CM 451.xx–453.xx or 997.2x) and/or pulmonary embolism (PE) (ICD-9-CM 415.1x) and at least 18 months of continuous enrollment. An index VTE was identified as the earliest diagnosis, inpatient or outpatient, of VTE. Inpatient admissions with a primary or secondary diagnosis of VTE following the index event were recurrent events. Statistical comparisons were conducted to test for differences in event rates between dalteparin and warfarin. Results: Of the 27,245 patients identified with cancer and a diagnosis of DVT/PE, 9,820 (36.0%) were male and the mean age was 51.0±9.7 years. Of those, 253 patients were treated with dalteparin, 41.9% male (50.7±9.8 years) and 12,453 were treated with warfarin, 41.8% male (52.3±8.9 years). The recurrent VTE rate for the entire population was 5.63%. Patients treated with dalteparin had a recurrence rate of 2.77% compared to 6.26% for those treated with warfarin (P=0.0009). The relative risk reduction between the groups was 55.8%. The rate for major bleeding events for dalteparin was 4.74% compared to 8.26% for warfarin (P=0.0096). Conclusions: Dalteparin was associated with fewer recurrent VTE and major bleeding events in cancer patients in comparison to those treated with warfarin. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Eisai Eisai