['myeloma', 'venous thromboembolism']
['apixaban']

        Inclusion Criteria:

          -  Patients (men/women) aged more than 18 years

          -  All consecutive patients, with myeloma, in first-line treatment or in relapse, who are
             treated - With IMiDs (MPT, Melphalan -Prednisone -Thalidomide ; Lenalidomide -
             Dexamethasone).

        AND

        - who require prevention of venous thromboembolic events with Aspirin or Low molecular
        Weight Heparin (LMWH) for a minimum duration of 6 months At least, 2/3 of patients will be
        treated with Lenalidomide-Dexamethasone.

          -  Written informed consent

          -  Patients affiliated to the French social security system or equivalent

        Exclusion Criteria:

          -  Patient who needs curative anticoagulant treatment (heparin, LMWH, vitamin K
             antagonists, Dabigatran, Rivaroxaban, Apixaban) for an associated disorder (mechanical
             valve, atrial fibrillation or venous thromboembolic disease in the previous 6 months).

          -  Patient who needs preventive treatment with an anticoagulant in a post-operative
             context

          -  Patient who needs anti-platelet treatment (Aspirin, Clopidogrel, Prasugrel, Ticagrelor
             or dual anti-platelet therapy )

          -  Patient with active bleeding or at a high risk of bleeding (ulcer disease,
             intracranial bleeding in the previous 6 months, uncontrolled hypertension)

          -  Patient having undergone a surgical intervention within the past 30 days likely to
             expose them to an haemorrhagic risk

          -  Active hepatic disease (hepatitis, cirrhosis)

          -  Severe renal insufficiency (creatinine clearance using the Cockcroft equation < 30
             ml/mn)

          -  Known allergic reaction to Apixaban

          -  Contraindication to the use of an anticoagulant treatment

          -  Prohibited concomitant treatment

               -  inhibitors of CYP3A4 and P-gp : azole antimycotic agents (ketoconazole,
                  itraconazole, voriconazole, posaconazole), inhibitors of HIV protease (ritonavir,
                  indinavir, nelfinavir, atazanavir, saquinavir), specific macrolide antibiotics
                  (clarithromycine, telithromycine)

               -  other antithrombotic treatment : salicylate derivates (aspirin, products
                  containing aspirin), antiplatelet therapy, heparin (unfractionated heparin, low
                  molecular weight heparin, danaparoide sodique, fondaparinux), hirudines, oral
                  anticoagulants (vitamin K antagonists, rivaroxaban, dabigatran)

          -  Patient with AST or ALT rate > 3 times upper limit of normal

          -  Patient with Bilirubin rate > 1.5 times upper limit of normal

          -  Patient with Platelets rate < 75 G/l

          -  Patient with Creatinine Clearance (Cockcroft) < 30 ml/mn

          -  Incidental finding of a proximal Deep Venous Thrombosis on the screening ultrasound

          -  Patients refusing or unable to give a written consent of information

          -  Patient unable to comply with the protocol requirement, in the investigator's opinion

          -  Life expectancy less than 6 months

          -  Incarcerated patients

          -  Pregnancy or possibility of pregnancy within 6 months

          -  Females of childbearing potential without reliable contraception

          -  Ecog > 2
      