As a clinical pharmacist, you'll continue to see a shift toward direct oral anticoagulants (Eliquis, etc) for cancer-associated venous thromboembolism (VTE). We're used to seeing these patients on a low-molecular-weight heparin (LMWH), such as enoxaparin (Clexane) or warfarin (Marevan) as an alternative. But evidence with DOACs is stacking up for VTE due to cancer.
Treatment. Most DOACs work about as well as LMWH to treat VTE in cancer, but there are no data yet with Pradaxa (dabigatran). Expect to see Eliquis (apixaban) or Xarelto (rivaroxaban). Savaysa (edoxaban) must be "bridged" with 5 to 10 days of an injectable anticoagulant. But anticipate injectable LMWH for patients with Gastreintestinal tumors or a history of GI bleeding due to higher GI bleeding risk with DOACs. Continue to recommend warfarin when CrCl is below 30 mL/min or cost is an issue. Advise treating for at least 3 to 6 months and as long as the patient is receiving cancer therapy or has active cancer.
Prophylaxis. Be aware that guidelines now recommend assessing VTE risk when outpatients start chemotherapy. Consider using the Khorana score to assess if outpatients with a solid tumor or lymphoma may benefit from anticoagulation. Risk is based on cancer type, high platelets or white count, low hemoglobin or prescribed a red cell growth factor and BMI over 35. Help weigh benefits and risks if the score is 2 or higher. Explain that withOUT prophylaxis, a score of 2 predicts up to 5 in 100 patients may develop a symptomatic VTE over 2.5 months or over 7 in 100 patients with scores of 3 or above. But caution about bleeding.
Advise against prophylaxis for patients with recent bleeding, platelets below 50,000/mcL, or limited life expectancy. When prophylaxis is appropriate, recommend Eliquis, Xarelto, or LMWH for up to 6 months. These are the only options shown to reduce the risk of VTE versus placebo. Expect low doses for prophylaxis, such as Eliquis 2.5 mg BID. Continue to watch for warfarin or DOAC interactions. For more information, see notes on, "How to manage direct oral anticoagulants (DOACs) around Surgery?!" AND "Note on treating venous thromboembolism (VTE)".
REFERENCES
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Key, N.S., Khorana, and others (2020). Venous Thromboembolism Prophylaxis and Treatment in Patients With Cancer: ASCO Clinical Practice Guideline Update. Journal of Clinical Oncology, 38(5), pp.496–520. Available at: https://pubmed.ncbi.nlm.nih.gov/31381464
Agnelli, G., Becattini, C., and others (2020). Apixaban for the Treatment of Venous Thromboembolism Associated with Cancer. New England Journal of Medicine, 382(17), pp.1599–1607. Available at: https://www.nejm.org/doi/full/10.1056/NEJMoa1915103