Comparison Of Sequential Vs Alternating Administration Of Bortezomib, Melphalan and Prednisone (VMP) and Lenalidomide Plus Dexamethasone (Rd) In Elderly Patients With Newly Diagnosed Multiple Myeloma (MM) Patients: GEM2010MAS65 Trial

Background VMP and Rd are two of the most efficient and widely accepted regimens in the treatment of elderly newly diagnosed MM patients. In order to further improve the outcome of elderly patients, one possibility would be to use regimens including all these drugs simultaneously, but this may result into high toxicity. Alternatively, the use of these regimens (VMP and Rd) in a sequential or alternating scheme could improve the treatment of elderly patients. We hypothesized the alternating scheme would minimize the emergence of resistant clones, and would reduce the cumulative toxicity. In order to test this hypothesis we decided to compare VMP and RD in a sequential vs an alternating scheme. Patients and methods 241 patients were randomized to receive a sequential scheme consisting on 9 cycles of VMP followed by 9 cycles of Rd or the same regimens in an alternating approach (one cycle of VMP alternating with one Rd (half of the patients started by VMP and half by Rd) up to 18 cycles). VMP included the iv administration of bortezomib 1.3 mg/m2 twice weekly for 1 six-weeks cycle, followed by once weekly for 8 four-weeks cycles in combination with oral melphalan 9 mg/m2 and prednisone 60 mg/m2 once daily on days 1–4 of each cycle. Rd treatment consisted on lenalidomide 25 mg daily on days 1-21 plus dexamethasone 40 mg weekly. Results 121 patients were allocated to receive the sequential scheme and 120 the alternating regimen. Both arms were well balanced according to the baseline characteristics. 52% patients in the sequential arm and 55% in the alternating and had high risk cytogenetic abnormalities (t(4;14), t(14;16), del17p or 1q gains). After 9 cycles of treatment, in the sequential arm, 35 out of 66 (54%) achieved at least VGPR vs 51 out of 65 patients (78%) in the alternating arm (p=0.002), including sCR/CR rate of 28% vs 38% in the sequential and alternating arms, respectively (p=NS). Seven patients in each arm achieved immunophenotypic CR. Moreover, while four patients progressed in the sequential arm under treatment with VMP, no patients in the alternating scheme developed disease progression during the first 9 cycles, After a median follow up of 12 months, there was a trend for shorter TTP in the sequential as compared with the alternating scheme (18 m-TTP of 83% vs 89% (p=NS)). In terms of OS, 83% of patients in the sequential arm were alive at 18 m versus 93% in the alternating (p=NS). Patients who achieved sCR/CR had a significantly longer 18 m-TTP as compared with patients who didn’t achieve it in both sequential (100% vs 71%; p=0.006) and alternating arms (100% vs 79%; p=0.006) and this translated into a significant benefit in OS. No differences were observed in overall response rates and CR rates in standard and high risk patients. The 18 m-TTP was similar in standard and high risk groups in both sequential (86% vs 81%) and alternating arms (84% vs 94%), noting that 94% of patients receiving the alternating scheme were progression-free at 18 months. Regarding hematologic toxicity, the frequency of G3-4 neutropenia was slightly lower in the sequential than in the alternating arm (16% and 23%) and the same trend was observed for G3-4 thrombocytopenia (16% vs 20%). Concerning non-hematologic toxicity, 5% and 4% of the patients in the sequential and alternating arms developed G3-4 infections, respectively; the rate of G3-4 skin rash was 4% in the sequential and 3% in the alternating arm; 4% of patients in the sequential arm developed G3-4 peripheral neuropathy and 3% in the sequential arm. The rate of grade 3-4 thrombotic events was 2% in both arms. Nevertheless, the detailed evaluation of the toxicity will be done at the completion of the trial when all patients will have received the same amount of drugs in either a sequential or an alternating scheme (at the present time, 42 patients in the sequential arm were not yet at risk for the development of lenalidomide-related side effects). Conclusions The administration of melphalan, bortezomib, lenalidomide and steroids in elderly MM patients in a sequential or alternating scheme is feasible. Although longer follow-up is necessary, the alternating scheme may be superior in terms of response rate and outcome, as result of the early exposure of the plasma cell to different agents. Toxicity profile is acceptable. Aparently both schemes of therapy seems to overcome the poor prognosis of high risk cytogenetic. Disclosures: Mateos: Janssen, Celgene: Honoraria. Off Label Use: Lenalidomide plus dexamethasone is not approved for newly diagnosed MM patients. Ocio:Onyx: Consultancy, Research Funding; Novartis: Consultancy; Array Biopharma: Consultancy, Research Funding; Bristol Myers Squibb: Consultancy; Celgene: Consultancy, Research Funding. San Miguel:Janssen, Celgene: Membership on an entity’s Board of Directors or advisory committees.