Evaluation of the Use of Apixaban in Prevnetion of Thromboembolic Disease in Patients With Myeloma Trated With iMiDs

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