A Randomized Phase 3 Trial Of Melphalan-Lenalidomide-Prednisone (MPR) Or Cyclophosphamide-Prednisone-Lenalidomide (CPR) Vs Lenalidomide Plus Dexamethsone (Rd) In Elderly Newly Diagnosed Multiple Myeloma Patients

Background Rd and MPR are effective treatments in newly diagnosed multiple myeloma (NDMM) patients (pts). In this study we compared a non-alkylating containing regimen (Rd) vs alkylating-based regimens (MPR/CPR) in elderly transplant ineligible NDMM pts. Methods Patients were randomized (2:1) to receive nine 28-day cycles of MPR/CPR or Rd. MPR: lenalidomide 10 mg/day for 21 days; melphalan orally 0.18 mg/Kg for 4 days in pts 65-75 years old and 0.13 mg/Kg in >75 years pts; prednisone 1.5 mg/Kg for 4 days; CPR: cyclophosphamide orally 50 mg/day for 21 days in pts 65-75 years old and 50 mg every other day (eod) in >75 years pts; lenalidomide 25 mg/day for 21 days; prednisone 25 mg every other day. Rd: lenalidomide 25 mg/day for 21 days; dexamethasone 40 mg on days 1,8,15 and 22 in pts 65-75 years old and 20 mg in those >75 years. After induction, patients were randomized to receive maintenance with lenalidomide alone (10 mg/day for 21 days) or with prednisone (25 mg eod on days 1-28), until disease progression. The primary endpoint was progression-free survival (PFS). Results Between October 2009 and October 2012, 659 pts were enrolled ( MPR/CPR:439 and Rd:220), and 641 pts were evaluable (MPR/CPR:430 and Rd:211). Patient characteristics were well balanced in the 2 groups: median age was 73 years in both groups, 38% of pts were older than 75 years, 27% had ISS stage III in both groups, 21% of patients both in the MPR/CPR and in the Rd groups had unfavorable FISH profile [t(4;14) or t (14;16) or del17p]. After induction, the response rates were similar in the 2 groups: at least PR rate was 75% versus 79% (p=0.52) and CR rate was 9% versus 7% (p=0.35), in the MPR/CPR and Rd group, respectively. No significant difference in response rate were reported between two alkylating containing regimens. After a median follow-up of 21 months, the 2-year PFS was 55% in MPR/CPR and 49% in Rd (HR=0.86, 95% CI: 0.66-1.12, p=0.26), and 2-year OS was 84% in MPR/CPR and 80% in Rd (HR= 0.93, 95% CI: 0.60-1.41, p=0.71) At least one grade ≥3 hematological adverse event was reported in 51% with MPR/CPR and 29% with Rd (p<0.001), with a significant difference between the two alkylating agents (67% MPR and 31% CPR, p<0.001). At least one grade ≥3 extra-hematologic toxicities were similar in the two groups (31% with MPR/CPR and 28% with Rd, p=0.77). with no difference between two alkylating agents (31% both in MPR and CPR group). Second primary malignancies (SPM) were reported in 5 MPR patients (1 hematologic and 4 solid) in 1 CPR patient (hematologic) and in 2 Rd patients (both solid). Conclusion In a community-based population, triplet alkylating combinations did not lead to different PFS or OS clinical benefits over doublet therapy. Updated results will be presented at the meeting. Disclosures: Palumbo: Amgen: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Janssen Pharmaceuticals: Consultancy, Honoraria; Millenium: Consultancy, Honoraria; Onyx: Consultancy, Honoraria. Bringhen: Celgene: Honoraria. Giuliani: Celgene: Research Funding. Cavallo: Celgene: Honoraria; Celgene: Membership on an entity’s Board of Directors or advisory committees. Hajek: Celgene: Honoraria; Celgene: Consultancy. Boccadoro: Celgene: Consultancy, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Janssen-Cilag: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees.