A Phase III Study of Enoxaparin Vs Aspirin as Thromboprophylaxis for Newly Diagnosed Myeloma Patients Treated with Lenalidomide-Based Regimen.

Newly diagnosed myeloma (MM) patients who receive thalidomide-based regimens have a high risk of thromboembolic events. Preliminary studies on MM patients receiving a combination of lenalidomide (R) and dexamethasone have shown an increased incidence of thrombosis as well, with a calculated odds ratio of about 3.5 of developing thrombosis.

In a prospective, multicenter phase III trial (RV-MM-PI-209) newly diagnosed patients were treated with lenalidomide and low-dose dexamethasone (Rd) induction and subsequently randomized to receive consolidation with lenalidomide + melphalan + prednisone (MPR) or high dose melphalan (MEL200). In this sub-study we evaluated the safety and the efficacy of low-molecular weight heparin (LMWH) or low-dose aspirin (ASA) as anticoagulant prophylaxis during Rd induction and MPR consolidation. End-points were incidence of venous thromboembolism (VTE), acute cardiovascular events, sudden death, major and minor bleeding.

402 newly diagnosed MM patients were enrolled in the randomized trial RV-MM-PI-209. Treatment schedule included four 28 day cycles of lenalidomide (25 mg days 1–21) and low-dose dexamethasone (40 mg days 1,8,15,22) (Rd) as induction. As consolidation, patients were randomized to receive six 28-day cycles of melphalan (0.18 mg/kg days 1–4), prednisone (2 mg/kg days 1–4) and lenalidomide (10 mg days 1–21) (MPR, N=202) or tandem melphalan 200 mg/m2 with stem-cell support (MEL200, N=200). All eligible patients were randomly assigned to receive LMWH (Enoxaparin 40 mg/d, N=166) or ASA (Aspirin 100 mg/d, N=176) for the duration of the induction therapy and for consolidation therapy in the MPR group; 60 patients were excluded from this sub-study because of indication for anticoagulant/antiplatelet therapy or high-risk of bleeding.

Patient characteristics and distribution of major risk factors were similar in the two groups. At the time of the present analysis 381 and 130 patients are evaluable during Rd induction and consolidation respectively. During the induction phase, the overall incidence of any grade 3–4 thrombotic events was 1% in the LMWH group, 2,4% in the ASA group (p=.45). VTE, mostly of the lower limbs were equally distributed in the two groups (1%; p not significant), while pulmonary embolism was observed only in the ASA group (2%; p not significant). Median time to onset of thrombotic events for patients who received LMWH or ASA were 2.1 and 1 months, respectively. No acute cardiovascular events were observed and only minor bleeding was detected in the LMWH group (1%). During consolidation no thrombotic events were observed in the MPR group, only one central venous catheter thrombosis was observed in the MEL200 group.

The overall incidence of thrombotic events was less than 5% in all groups and confirmed the safety of low dose dexamethasone in association with Lenalidomide. No significant benefit was seen with LMWH over ASA in this patient population. LMWH and ASA are likely to be effective thromboprophylactic regimens in lenalidomide treated patients with newly diagnosed multiple myeloma. The analysis will be updated for the meeting.

Cavallo:CELGENE: Honoraria. Guglielmelli:CELGENE: Honoraria; JANSSEN-CILAG: Honoraria. Boccadoro:CELGENE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; JANSSEN-CILAG: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Palumbo:CELGENE: Honoraria, Membership on an entity's Board of Directors or advisory committees; JANSSEN-CILAG: Honoraria, Membership on an entity's Board of Directors or advisory committees.