Reduction to Preventive Doses of Enoxaparin After 3 to 6 Months of Treatment With Blood Thinners for Cancer-associated Blood Clots

Background: Venous thromboembolism (VTE), which includes deep vein thrombosis (DVT) and pulmonary embolism (PE), is the third most common cardiovascular disorder after myocardial infarction and stroke. VTE occurs in about 1 person per 1,000 per year, increasing dramatically in patients with cancer to about 25 per 1,000 per year. Among the known risk factors of VTE, cancer is one of the most potent. Patients with cancer have a 7- to 28-fold higher risk for VTE than non-cancer patients. VTE has important implications for the care of cancer patients, including reduced life expectancy, high rates of VTE recurrence both while on and after stopping anticoagulation, the need for chronic anticoagulation with related adverse drug reactions, and delays in cancer therapies. Clinical dilemma: Current clinical guidelines recommend a minimum of 3-6 months of anticoagulation with weight-adjusted low molecular weight heparin (LMWH) in cancer patients with VTE. However, there are no recommendations beyond the initial 6 months of therapy due to the lack of data on extended duration therapy for cancer-associated thrombosis (CAT). This leads to variability in physician practices, with some continuing weight-adjusted LMWH therapy beyond 6 months. This poses concern because, while the goal is to prevent recurrence of VTE, the risk of major bleeding with prolonged weight-adjusted LMWH therapy is significant. Potential solutions: There is a lack of data to inform on VTE treatment in cancer patients beyond the initial 3-6 months of anticoagulation. We propose that after a minimum of 3-6 months of therapeutic dose anticoagulation, the use of prophylactic doses of LMWH will have an acceptable and adherence profile in cancer patients with VTE. The data obtained from this study will help inform physician practices. Design: This is a multicentre, open-label study of enoxaparin (40 mg subcutaneous injection, once daily) for additional 6 months after an initial minimum 3-6-month course of therapeu