Melphalan, prednisone, thalidomide and defibrotide in relapsed/refractory multiple myeloma: results of a multicenter phase I/II trial.

BACKGROUND: Defibrotide is a novel orally bioavailable polydisperse oligonucleotide with anti-thrombotic and anti-adhesive effects. In SCID/NOD mice, defibrotide showed activity in human myeloma xenografts. This phase I/II study was conducted to identify the most appropriate dose of defibrotide in combination with melphalan, prednisone and thalidomide in patients with relapsed and relapsed/refractory multiple myeloma, and to determine its safety and tolerability as part of this regimen. DESIGN AND METHODS: This was a phase I/II, multicenter, dose-escalating, non-comparative, open label study. Oral melphalan was administered at a dose of 0.25 mg/kg on days 1-4, prednisone at a dose of 1.5 mg/kg also on days 1-4 and thalidomide at a dose of 50-100 mg/day continuously. Defibrotide was administered orally at three dose-levels: 2.4, 4.8 or 7.2 g on days 1-4 and 1.6, 3.2, or 4.8 g on days 5-35. RESULTS: Twenty-four patients with relapsed/refractory multiple myeloma were enrolled. No dose-limiting toxicity was observed. In all patients, the complete response plus very good partial response rate was 9%, and the partial response rate was 43%. The 1-year progression-free survival and 1-year overall survival rates were 34% and 90%, respectively. The most frequent grade 3-4 adverse events included neutropenia, thrombocytopenia, anemia and fatigue. Deep vein thrombosis was reported in only one patient. CONCLUSIONS: This combination of melphalan, prednisone and thalidomide together with defibrotide showed anti-tumor activity with a favorable tolerability. The maximum tolerated dose of defibrotide was identified as 7.2 g p.o. on days 1-4 followed by 4.8 g p.o. on days 5-35. Further trials are needed to confirm the role of this regimen and to evaluate the combination of defibrotide with new drugs.

The treatment of the elderly multiple myeloma patients.

Multiple myeloma (MM) is an incurable malignancy of the plasma cells. Most patients are diagnosed when they are older than 65 years. Therapeutic options include chemotherapy, using either established (e.g. melphalan) or newly available (e.g. thalidomide) drugs and high-dose treatment with stem-cell support (autologous as well as allogeneic). Recent research has focused on defining the target population for the different therapeutic approaches, taking into account pre-treatment characteristics of patients, particularly age, and aims to balance treatment benefit with potential adverse events. In this review we present the data available on the most recent trials dealing with the treatment of elderly MM patients.

Intermediate-dose melphalan (100 mg/m2)/bortezomib/thalidomide/dexamethasone and stem cell support in patients with refractory or relapsed myeloma.

BACKGROUND: Bortezomib and thalidomide have shown synergy with melphalan and dexamethasone. We used this 4-drug combination as conditioning before autologous hematopoietic cell infusions. PATIENTS AND METHODS: Twenty-six patients with advanced-stage myeloma were treated with melphalan 50 mg/m(2) and bortezomib 1.3 mg/m(2) on days -6 and -3 in association with thalidomide 200 mg and dexamethasone 20 mg on days -6 through -3, followed by hematopoietic cell support on day 0. RESULTS: Nonhematologic toxicities included pneumonia, febrile neutropenia, and peripheral neuropathy. All patients had undergone autologous transplantation at diagnosis, and 13 patients (50%) underwent an additional transplantation at relapse. Responses occurred in 17 of 26 patients (65%), including 1 complete remission, 3 near complete remissions (12%), and 2 very good partial remissions (8%). Response rate was higher than that induced by the previous line of treatment in 12 patients (46%). CONCLUSION: Melphalan/bortezomib/thalidomide/dexamethasone showed encouraging antimyeloma activity in patients with advanced-stage myeloma.

Oral melphalan at diagnosis hampers adequate collection of peripheral blood progenitor cells in multiple myeloma.

BACKGROUND AND OBJECTIVES: Since optimal collection of peripheral blood progenitor cells (PBPC) remains crucial for high-dose therapy in patients with multiple myeloma (MM) in relapse phase or refractory to chemotherapy, we evaluated several variables that may influence mobilization. DESIGN AND METHODS: Eighty-nine patients who underwent a standard mobilization procedure with cyclophosphamide (3 g/m2) and growth factors entered the study. A composite collection totalling at least 2x106 CD34+/kg was defined as a sufficient yield: 59 patients achieved an adequate collection. A reliable factor to predict adequate yields was prior therapy: an adequate collection was obtained in 92% of patients treated with conventional non-alkylating therapy (VAD-based regimens), in 56% treated with oral melphalan and in 23% who had received intravenous melphalan. RESULTS: The three groups were similar for most clinical features. After adjustment for several potential confounders, the probability of an adequate PBPC collection remained higher in the group treated with non-alkylating agents, with an odds ratio (OR) of 6.14 (95% confidence interval, CI=1.34, 28.13) and lower in those treated with intravenous melphalan (OR=0.08; CI=0.01-0.61), when compared to the group treated with oral melphalan. Among the other prognostic factors (stage, percentage of bone marrow plasma cells, b2-microglobulin, labeling index, isotype, monoclonal component, Bence-Jones proteinuria) evaluated at diagnosis, there was no clear association with progenitor cell yield. INTERPRETATION AND CONCLUSIONS: In conclusion, patients who are potential candidates for high-dose therapy with PBPC support should not receive conventional alkylating therapy, even orally. Alternatively, progenitor cells should be collected early in the course of MM.

Intermediate-dose melphalan improves survival of myeloma patients aged 50 to 70: results of a randomized controlled trial.

High-dose therapy is an effective standard treatment for multiple myeloma patients. Evidence that intermediate-dose therapy improves survival is limited. At diagnosis, about 70% of patients are older than 65. Intermediate-dose regimen is very well tolerated in older patients. In a multicenter study, 194 patients were randomized to receive at diagnosis either conventional chemotherapy (6 courses of oral melphalan and prednisone [MP]) or intermediate-dose therapy (2 courses of melphalan at 100 mg/m(2) [MEL100]) with stem cell support. Response rate was higher after MEL100. Near-complete remission (nCR) was 6% after MP and 25% after MEL100 (P = .0002). At 3 years, MEL100 increased event-free survival (EFS) from 16% to 37% and overall survival (OS) from 62% to 77% (P < .001). Similar results were observed in patients aged 65 to 70: nCR was 8% after MP and 25% after MEL100 (P = .05); at 3 years, MEL100 improved EFS from 18% to 31% (P = .01) and OS from 58% to 73% (P = .01). Patients aged 65 to 70 had a median OS of 37.2 months (MP) versus 58 months (MEL100). Intermediate-dose melphalan improves response rate, EFS, and OS in myeloma patients, specifically in those aged 65 to 70. It constitutes a more effective first-line regimen than standard treatment for elderly patients.