Treatment of multiple myeloma: a randomized study of three different regimens

Complications of myeloma therapy

The advent of new therapies for multiple myeloma brings new hope for patients but also new side effects. Emerging information about the risks of supportive care therapies, including long-term, high-intensity bisphosphonate use and erythropoiesis-stimulating agents, is examined. As the number of drugs in the myeloma armamentarium grows, so does the list of possible side effects and interactions. With current progress, not only are there more complications to consider but patients are also living longer and the risk for delayed complications is becoming more relevant. The author provides perspective about the risks for the most active and commonly used single-agent and combination myeloma therapies.

Melphalan and Prednisone (MP) Regimen for Multiple Myeloma

The increasing complexity of cancer chemotherapy makes it mandatory that pharmacists be familiar with these highly toxic agents. This column focuses on the commercially available and investigational agents used to treat malignant diseases and reviews issues related to the preparation, dispensing, and administration of cancer chemotherapy.

Intravenous melphalan and dexamethasone followed by lymphoblastoid alpha interferon in higher risk multiple myeloma patients

Intermittent courses of melphalan and prednisone is still the standard chemotherapy for the initial treatment of multiple myeloma (MM) in patients who cannot undergo high-dose chemotherapy/radiotherapy with either allogeneic or autologous stem cell transplantation. However, the absorption of the drug from the gastrointestinal tract is highly variable from patient to patient and therefore, different plasma levels of the drug are reached in the blood of individual MM patients. In order to overcome this limitation we decided to use intermediate dose (15-30 mg/m2, day 1) intravenous melphalan in resistant or relapsing MM patients as well as in untreated patients not eligible for a more aggressive protocol. Moreover, considering the good results obtained by other investigators using dexamethasone alone or associated with interferon in the treatment of resistant or relapsing MM patients, dexamethasone (40 mg total dose, day 1) and the lymphoblastoid alpha interferon (3 MU, 3 times a week x 3 weeks, from day 8 to day 26 of each course) were added to intravenous melphalan. Courses were repeated every 5 weeks for a total of 6 cycles. We treated 62 MM patients obtaining a response (defined as reduction > 25% of the initial monoclonal component value associated with disappearance of the clinical symptoms) in 38 out 62 evaluable patients (61%) and stable disease (defined as a decrease of < 25% in the base-line serum monoclonal component level with disappearance of all symptoms present at diagnosis) in 9 (14.5%) more patients. The overall median response duration was 14 months and the overall median survival duration (from the time of inclusion in this protocol) for the 62 patients entered into the study was 34 months. No severe (Grade 3-4 of the WHO) hematological as well as non hematological toxicities were observed. This lack of severe toxicity allowed us to administer the drugs on an outpatient basis. In conclusion, the overall response and the low grade of toxicity in this category of patients are encouraging and suggest that this protocol is both effective and safe treatment for high risk MM patients.

Treatment of multiple myeloma in elderly patients. New developments

The median of survival among patients with multiple myeloma (MM) is about 30 months from the onset of treatment. Tumour burden and a range of other parameters, such as C-reactive protein levels, the plasma cell labelling index and beta2-microglobulin levels, can be used to assign patients to favourable and unfavourable prognostic groups. Conventional chemotherapy consists of melphalan and prednisone, and is as effective as moderately intensive cytotoxic drug regimens. Although second-line chemotherapy is initially effective, all patients eventually die. Maintenance therapy will interferon-alpha prolongs the plateau phase of the disease, but its effects on overall survival are minimal. One of the promising developments in the treatment of MM has been the introduction of high dosage chemotherapy, which can now be safely administered when stem cells are used for haematological recovery. Autologous bone marrow transplantation has been shown to produce a significant improvement in survival compared with conventional therapy. Several studies are under way that are examining the effects of multiple courses of high dosage chemotherapy together with peripheral stem cell support. Purging of autologous stem cell harvests will be performed in the near future to minimise contamination with myeloma cells. It is now feasible to use high dosage chemotherapy, with the support of granulocyte colony-stimulating factor-stimulated whole blood, in selected elderly patients. Besides the promising development of intensive therapy, a number of other treatment strategies have emerged, including treatment with monoclonal antibodies against interleukin-6 and multidrug resistance-modulating agents. Better supportive care can be provided for some patients by using epoetin (recombinant human erythropoietin), and the sequelae of lytic bone lesions can be ameliorated through the use of bisphosphonates.

Diagnosis, prognosis, and standard treatment of multiple myeloma

The diagnosis of multiple myeloma (MM) is often difficult; most patients present with asymptomatic gammopathy. The only findings that confirm a diagnosis of MM are an elevation in the M-component or extension of the lytic bone lesions that are the hallmark of the disease. Tests that delineate plasma cell biology, such as plasma cell proliferation rate, are helpful; magnetic resonance imaging can disclose bone marrow lesions leading to subsequent osteolytic disease. After the diagnosis of MM has been established and prognostic factors identified, the appropriate therapy can be determined. Melphalan and prednisone are no longer considered to be the "gold standard" of therapy. In fact, this approach is suitable for less than half of patients with myeloma. This article presents guidelines for standard treatment options and examines the efficacy of new high-dose chemotherapy approaches.

A prognostic index for multiple myeloma

The current prognostic systems have failed to identify multiple myeloma (MM) patients who require aggressive therapy. These staging systems do not reliably distinguish patients with different prognoses. This paper explores the possibility of improving the prognostic forecast in MM by considering some clinical characteristics at diagnosis together with response to first-line chemotherapy. A total of 231 patients were prospectively randomised in a multicentre trial to no therapy vs melphalan + prednisone (MP) for stage I, MP in stage II, and MP vs peptichemio, vincristine and prednisone for stage III. The clinical features of these groups were evaluated for prognostic variables predictive of overall survival by means of univariate and multivariate analysis. The independently significant variables were incorporated into a model that identified three groups of patients with different risks of death and different overall survival. Three variables retained statistical significance: the staging system proposed by the British Medical Research Council, a composite parameter integrating the percentage of bone marrow plasma cells with cytological features of the infiltrating elements (plasma cell vs plasmablast), and response to 6 months of first-line chemotherapy. These three variables led the proposal of a scoring system able to identify three different risk classes (with median overall survival of 52, 28 and 13 months respectively) and to estimate individual patient prognosis more flexibly. The proposed risk classes, drawn from both diagnostic and therapeutic parameters, are thought to be a clinical and investigational instrument for separating MM patients into comparable groups, for selecting the best available therapy and for evaluating response with respect to the disease of each new patient.

No correlation between response and survival in patients with multiple myeloma treated with vincristine, melphalan, cyclophosphamide, and prednisone

A vincristine, melphalan, cyclophosphamide, and prednisone (VMCP) multi-drug regimen was used in 85 previously untreated patients with multiple myeloma (MM) (symptomatic Durie Stages II and III) until they became refractory. The prognostic significance of various pretreatment characteristics was evaluated in terms of therapeutic response (according to Southwest Oncology Group [SWOG] and Chronic Leukemia-Myeloma Task Force [TF] criteria) and survival. Therapeutic responses, obtained in 31.2% (SWOG) and 68.7% (TF) of patients, had a significant inverse correlation with myeloma cell mass, serum calcium, and bone status. Median survival time of Stage II and Stage III patients was 39 and 34 months, respectively. Serum B2 microglobulin greater than or equal to 6 micrograms/ml was the only variable correlating unfavorably with survival duration after multi-variate analysis (increased risk = 2.79), although therapeutic response as a time-dependent variable had no effect on survival. These data suggest no correlation between response and survival, partially because of inadequate response assessment criteria and partially because no existing treatment is curative (although current therapeutic approaches may prevent death from complications).

Alpha-2a-interferon/melphalan/prednisone versus melphalan/prednisone in previously untreated patients with multiple myeloma

Alpha-2a-interferon (IFN) has demonstrable activity in advance and refractory multiple myeloma (MM), because of the in vitro synergism between IFNs and cytotoxic agents we report the preliminary results of a therapeutic trial of 50 patients with MM. Twenty-eight patients were randomized to receive melphalan plus prednisone (MP) and 22 were randomized to receive IFN plus MP (IFN-MP). Criteria for response, progression and relapse were those of the Southwestern Oncology Group. 95% of the patients receiving IFN-MP responded to therapy as opposed to 68% of the patients receiving MP (P less than 0.05). Response was independent of M-component immunoglobulin class but in stage III it was higher in the IFN-MP group than in the MP group (P less than 0.05). The combination IFN-MP was well tolerated without unusual or unexpected toxic effects. The response duration time was longer in the IFN-MP group than in the MP group (P less than 0.025). The median survival was 80 weeks in the MP group and in the IFN-MP group the 93% of patients were still alive after 90 weeks (P less than 0.025). Our results show that the use of the IFN as an adjuvant to MP improves the percentage of responders, the response duration time and the median survival of untreated patients with MM.

A randomized multicentric study comparing alternating combination chemotherapy (VCMP/VBAP) and melphalan-prednisone in multiple myeloma

Between January 1985 and December 1988, 386 patients with multiple myeloma were randomized to receive either MP or combination chemotherapy based on alternating cycles of VCMP and VBAP. The major prognostic parameters did not differ significantly between both treatment groups. A significantly higher proportion of objective responses was observed with combination chemotherapy as compared to MP (47.8 vs 32.2, P = 0.01). The median survival for all patients was 33.5 months. So far no significant differences were found when comparing the survival curves from both groups of patients. However, the median survival of MP-treated patients is 26.8 months, whereas the median survival of patients receiving VCMP/VBAP has not yet been reached. The definitive analysis must await the evaluation of all patients entered into the study and a longer follow-up time.

Myeloma

Myeloma is a malignancy of plasma cells that are terminally differentiated B-lymphocytes. The clinical spectrum varies from the incidental discovery of a pathologically raised monoclonal immunoglobulin on routine electrophoresis in asymptomatic patients to widespread skeletal involvement with incapacitating bone pain. Symptoms may result from a solitary tumor mass, described as an extramedullary plasmacytoma, in virtually any part of the body. Metabolic abnormalities commonly include hypercalcemia, elevated plasma urate levels, or the development of amyloidosis, all of which may disturb renal function. High paraprotein levels cause hyperviscosity, resulting in generalized debility and varying degrees of disturbed mental function. The natural history is determined by the mass of the tumor coupled with its unique biologic features. Median survival of unselected patients, without effective treatment but once symptoms are evident, is approximately 7 months; this period can be significantly prolonged with appropriate therapy. As a first step, urgent medical management is often necessary, centering on rehydration, correction of hyperviscosity, and reversal of metabolic defects, each of which may improve renal function. Over the longer term, specific antitumor drugs have extended median survival to approximately 30 months, and most regimens include a combination of melphalan and prednisone, with or without other cytotoxic drugs. Alternative forms of treatment include sequential hemibody irradiation, recombinant alpha interferon, and in suitably selected patients, high-dose chemoradiotherapy followed by bone marrow transplantation. The latter approaches offer promising management options and are currently the subject of evaluation in controlled clinical trials.

Initial treatment in multiple myeloma: no advantage of multidrug chemotherapy over melphalan-prednisone. The Myeloma Group of Western Sweden

From October 1983 until December 1986, 164 patients with multiple myeloma stage II-III were included in a prospective randomized multi-centre study comparing melphalan-prednisone (MP) with multidrug chemotherapy (MDC). The patients comprised 77% of all newly diagnosed myeloma stage II-III cases reported from 18 hospitals covering the entire Health Care Region of Western Sweden (1.5 million inhabitants). Patients randomized to MP (29 stage II and 55 stage III patients) were given oral melphalan and prednisone every 6 weeks. For patients randomized to MDC, stage II patients (n = 25) were given VMCP every 4 weeks and stage III patients (n = 53) VBAP and VMCP alternately every 4 weeks. For stage II patients, the response rate for MP compared to VMCP was 69 versus 56% and the median survival 46 versus 33 months. For stage III the response rate for MP compared to VBAP/VMCP was 58 versus 57% and the median survival 26 versus 24 months. No statistically significant differences were seen. The time to response and remission duration were also similar in both treatment arms. The dose intensity index (cumulative given/planned dose of myelosuppressive drugs) was greater than or equal to 0.8 in 89% of the MP patients and 81% of the MDC patients. Patients with index values less than 0.8 had the same response rate as patients with index greater than or equal to 0.8. This study has not demonstrated any advantage of MDC over traditional MP in multiple myeloma stage II-III.

Intermediate-dose (25 mg/m2) intravenous melphalan for patients with multiple myeloma in relapse or refractory to standard treatment

Intermediate-dose (25 mg/m2) intravenous melphalan has been evaluated in 34 multiple myeloma patients refractory to standard chemotherapies. The median time from diagnosis to entering of patients into the study was 27 months (range 7-71 months). A response was obtained in 12/34 patients (35%). 4 of 12 responding patients have relapsed and 2 of these have died; 8 responders have not relapsed and are still alive. The median duration of survival after 28 months of follow-up has not yet been reached in the group of patients responding to treatment. However, the overall median duration of survival for the 34 patients entered into the study was 8 months. The median duration of response was 16 months. Toxicity was limited to leukopenia, thrombocytopenia, nausea and vomiting. This lack of severe toxicity allowed us to administer the drug on an outpatient basis. The response rate and the low toxicity observed in this group of patients are encouraging and suggest that intermediate-dose intravenous melphalan is an effective and safe second line treatment for patients with multiple myeloma not responding to conventional treatment.

Induction and maintenance therapy in multiple myeloma: a multicenter trial of MP versus VCMP

In a prospective multicenter trial, 320 untreated myeloma patients of stage II and III were randomized for remission induction into two groups receiving six monthly courses of either MP or VCMP treatment. Response rates were equal in both groups: 72% remission, 21% no change, 7% progress for patients evaluable by TCM changes and 56% remission, 11% no change, 33% progress for BJ- and non-secretory myelomas. The overall survival rate was 60% after 4 years. An unexpected finding was the significantly longer survival of MP treated patients compared to the VCMP group. After successful remission induction, patients were randomized into one group receiving maintenance treatment using the induction scheme q 8 weeks, and another group without further chemotherapy. Although patients in the latter group relapsed significantly earlier, differences between both groups concerning acquired resistance to first line therapy or survival have not been noticed to date.