Joth Jacobson

Virtually no progress has been made during more than 2 decades of clinical trials for multiple myeloma (MM) involving standard therapy (ST). Recent studies suggest that dose intensification requiring hematopoietic stem cell support results in higher complete response (CR) rates and extended disease control. "Total Therapy" (TT) consisting of noncross-resistant induction regimens, followed by a double autotransplant (AT) procedure, was administered to 123 untreated patients with symptomatic MM. Upon hematologic recovery, interferon (IFN) maintenance (3 million units [MU]/m2 subcutaneously thrice weekly) was given until disease recurrence/progression. Results were compared with the outcome of untreated patients receiving ST according to Southwest Oncology Group (SWOG) trials. One hundred sixteen pair mates were selected from both TT and among 1,123 patients to match for the major prognostic features. TT induced CR in 40% of all 123 patients (intent-to-treat). By 12 months, 7% had died, including 4% from treatment-related complications. With a median follow-up of 31 months, median durations of event-free survival (EFS) and overall survival (OS) are 49 and 62+ months, respectively. Abnormalities of chromosomes 11q and 13 were associated with inferior outcome, whereas CR within 6 months after induction was a favorable prognostic feature for both EFS and OS. In comparison to ST, TT induced higher PR rates (85% v 52%, P < .0001) (CR rates not available on SWOG trials) and extended EFS (49 v 22 months, P = .0001) and OS (62+ v 48 months, P = .01). Compared to ST, dose intensification with double AT markedly augments tumor cytoreduction, effecting not only higher CR rates but also significantly extending EFS and OS in previously untreated patients with MM.

Autologous peripheral blood stem cell (PBSC)-supported high-dose melphalan is now considered standard therapy for myeloma, at least for younger patients. The markedly reduced toxicity of allotransplants using nonmyeloablative regimens (mini-allotransplantations) may hold promise for more widely exploiting the well-documented graft-versus-myeloma (GVM) effect. New active drugs include immunomodulatory agents, such as thalidomide and CC-5013 (Revimid; Celgene, Warren, NJ), and the proteasome inhibitor, PS 341 (Velcade; Millenium, Cambridge, MA), all of which not only target myeloma cells directly but also exert an indirect effect by suppressing growth and survival signals elaborated by the bone marrow microenvironment's interaction with myeloma cells. Among the prognostic factors evaluated, cytogenetic abnormalities (CAs), which are present in one third of patients with newly diagnosed disease, identify a particularly poor prognosis subgroup with a median survival not exceeding 2 to 3 years. By contrast, in the absence of CAs, 4-year survival rates of 80% to 90% can be obtained with tandem autotransplantations. Fundamental and clinical research should, therefore, focus on the molecular and biologic mechanisms of treatment failure in the high-risk subgroup.

A group of 256 newly diagnosed myeloma patients were enrolled in a phase III study that included 4 monthly cycles of induction chemotherapy and tandem transplant. All patients were randomized to either receive or not receive thalidomide. A total of 221 patients (86%) received no prophylactic anticoagulation (cohort I); 35 patients received low dose coumadin (cohort II). The incidence of deep vein thrombosis (DVT) was significantly higher in the thalidomide arm hazard ratio: 4.5; P < 0.0001). As low dose coumadin (1 mg/d) failed to decrease thrombotic complications in 35 patients (cohort II), low molecular weight heparin (LMWH, enoxaparin 40 mg s.c. q.d.) was instituted as DVT prophylaxis in the thalidomide-treated patients (n = 68) of the subsequent cohort (n = 130, cohort III). This intervention eliminated the difference in DVT incidence between the two arms (thalidomide and no thalidomide). Within cohorts I and II, 36 patients, in whom thalidomide was discontinued after experiencing a thrombotic episode during chemotherapy, subsequently resumed the drug on full anticoagulation; with a median follow-up of 22 months, DVT recurred in four patients (11%). After completing induction and tandem transplantation, 55 patients were re-exposed to thalidomide and chemotherapy during consolidation treatment. Thrombotic complications were observed in 4%. Our experience, although not based on a randomized study, suggests that the excess frequency of thrombosis in patients treated with chemotherapy and thalidomide can be safely reduced by the prophylactic use of LMWH. The rate of DVT recurrence observed in our study upon thalidomide resumption was sufficiently low to allow its continuation in patients who may benefit from this therapeutic intervention.

PURPOSE: To improve outcome in previously treated patients (at least two cycles of standard therapy) with multiple myeloma, thalidomide was combined with cytotoxic chemotherapy as induction therapy. PATIENTS AND METHODS: The regimen consisted of 4-days of oral dexamethasone, daily thalidomide, and 4 days of continuous-infusion cisplatin, doxorubicin, cyclophosphamide, and etoposide (DTPACE). Response to two cycles of DTPACE for induction was evaluated in 236 patients. Before being treated with DTPACE, 148 patients (63%) had shown progressive disease while receiving standard chemotherapy, and 55 patients (23%) had chromosome 13 abnormalities. RESULTS: The partial remission rate (PR) after two cycles of DTPACE was 32%, with 16% attaining a complete remission (CR) or near-CR (nCR; defined as only immunofixation electrophoresis-positive). Patients with high lactate dehydrogenase (LDH; n = 98) showed a better response than those with normal LDH (n = 138): PR or better, 43% v 27% (P =.01); CR + nCR, 25% v 11% (P =.01). Patients with chromosome 13 abnormalities (n = 55) responded equally well as the other patients (n = 181): PR or better, 35% v 33% (P =.84); CR + nCR, 17% v 15% (P =.73). Patients who received 100% dose of DTPACE for two cycles (n = 115) achieved higher response rates than those with less than 100% dose (n = 121): PR or better, 49% v 17% (P <.0001); CR + nCR, 27% v 6% (P <.0001). CONCLUSION: Combination therapy of oral dexamethasone and thalidomide with infusional chemotherapy is effective as induction therapy before autotransplantation, especially in patients with high-risk features.