Interferon versus interferon plus prednisone remission maintenance therapy for multiple myeloma: a Southwest Oncology Group Study

Maintenance Strategies Post-Autologous Stem Cell Transplantation for Newly Diagnosed Multiple Myeloma

Multiple myeloma, the second most common hematological malignancy worldwide, has demonstrated dramatic improvements in outcome in the last decade. In newly diagnosed patients, induction chemotherapy followed by autologous stem cell transplantation (ASCT) is the standard of care. After ASCT, the majority of patients experience disease remission but, despite recent therapeutic developments, most will eventually relapse. In this review we consider clinical aspects of maintenance therapies that can be used post-ASCT to prolong remission duration. We discuss the evidence for the effectiveness of each of these drugs as a maintenance therapy, alongside other benefits and drawbacks to their use, for example, route of administration and potential toxicities. We discuss questions which remain unanswered around the optimal use of currently available maintenance therapies and review newer agents being considered for use as maintenance such as emerging immunotherapies.

Impact of post-transplantation maintenance therapy on health-related quality of life in patients with multiple myeloma: data from the Connect® MM Registry

Maintenance therapy after autologous stem cell transplantation (ASCT) is recommended for use in multiple myeloma (MM); however, more data are needed on its impact on health-related quality of life (HRQoL). Presented here is an analysis of HRQoL in a Connect MM registry cohort of patients who received ASCT ± maintenance therapy. The Connect MM Registry is one of the earliest and largest, active, observational, prospective US registry of patients with symptomatic newly diagnosed MM. Patients completed the Functional Assessment of Cancer Therapy-MM (FACT-MM) version 4, EuroQol-5D (EQ-5D) questionnaire, and Brief Pain Inventory (BPI) at study entry and quarterly thereafter until death or study discontinuation. Patients in three groups were analyzed: any maintenance therapy (n = 244), lenalidomide-only maintenance therapy (n = 169), and no maintenance therapy (n = 137); any maintenance and lenalidomide-only maintenance groups were not mutually exclusive. There were no significant differences in change from pre-ASCT baseline between any maintenance (P = 0.60) and lenalidomide-only maintenance (P = 0.72) versus no maintenance for the FACT-MM total score. There were also no significant differences in change from pre-ASCT baseline between any maintenance and lenalidomide-only maintenance versus no maintenance for EQ-5D overall index, BPI, FACT-MM Trial Outcomes Index, and myeloma subscale scores. In all three groups, FACT-MM, EQ-5D Index, and BPI scores improved after ASCT; FACT-MM and BPI scores deteriorated at disease progression. These data suggest that post-ASCT any maintenance or lenalidomide-only maintenance does not negatively impact patients' HRQoL. Additional research is needed to verify these findings.

Consolidation and Maintenance Therapies for Newly Diagnosed Multiple Myeloma in the Era of Novel Agents

Advances in therapy in multiple myeloma have resulted in significant improvements in patient outcomes; however, relapse remains problematic. Strategies to improve outcomes following autologous stem cell transplantation (ASCT) include consolidation to intensify therapy and improve depth of response and maintenance therapy to achieve long-term disease control. Immunomodulatory drugs (IMiDs), including thalidomide and lenalidomide, are appealing as maintenance therapy given their oral administration; however, the cumulative toxicities of thalidomide have limited its efficacy in maintenance therapy. Maintenance lenalidomide is better tolerated, and multiple studies have demonstrated an improvement in progression-free survival (PFS), but its impact on overall survival (OS) remains controversial. Additional concerns regarding the risk of second primary malignancies and significant cost of long-term lenalidomide therapy have also been raised. Proteasome inhibitors, particularly, bortezomib have also been incorporated in consolidation and maintenance regimens alone or in combination with an IMiD. Preliminary studies have suggested bortezomib maintenance may benefit patients with adverse cytogenetics, including t(4;14) and deletion 17p. Determination of the optimal consolidation and maintenance regimen and duration of therapy post-transplantation is a focus of several ongoing randomized studies.

Maintenance therapy in multiple myeloma

Despite recent advances, multiple myeloma remains an incurable disease. Induction therapy followed by autologous transplantation has become the standard of care. The idea of maintenance therapy in multiple myeloma is not new. Starting with chemotherapy in 1975, to interferon in 1998, to novel agents recently, a multitude of agents have been explored in patients with multiple myeloma. In spite of the novel agents, multiple myeloma continues to be an incurable disease with the progression-free survival after autologous transplant rarely exceeding 3 years. The goal of using maintenance therapy has been to improve the outcomes following autologous transplantation by increasing the progression-free survival, deepening remissions and perhaps increasing overall survival. It has been shown that patients with a stringent complete response (CR) have a better outcome [Kapoor et al. 2013]. It is becoming increasingly common to check minimal residual disease (MRD) as a means of assessing depth of response. It has also been shown that patients with no MRD have not only a better progression-free survival but also a better overall survival compared with patients who are MRD positive. This makes it even more important to find agents for maintenance therapy, which can further deepen and maintain responses. Here, we present a comprehensive review of the agents studied as maintenance for multiple myeloma and their efficacy, both in terms of overall survival, progression-free survival and toxicity.

Sustained disease control in transplant-ineligible patients: the role of continuous therapy

Many patients with multiple myeloma (MM) are elderly (aged >65 years) or unfit, and therefore ineligible for stem-cell transplantation. The novel agents thalidomide, bortezomib, and lenalidomide have shown improved outcomes in these patients. This article discusses the role of continuous therapy in improving patient outcomes and how novel agents with better tolerability profiles could lead to a change in the treatment paradigm. According to the proposed concept, treatment of transplant-ineligible patients with MM should include achievement of high-quality responses with effective induction combination regimens, as well as maintenance of the response with long-term therapy for optimal sustained efficacy.

Evolving therapeutic paradigms for multiple myeloma: back to the future

Multiple myeloma (MM) is an ancient disease, but until the alkylating agent melphalan was found to have anti-myeloma properties in the 1950s there was virtually no effective therapy. By the late 1960s, extended dosing with melphalan and prednisone tripled survival from diagnosis and became the standard of care for newly diagnosed MM. "Maintenance therapy" to prolong survival through sustained disease control following induction chemotherapy was sought by 1970, but early strategies were ineffective and toxic. Subsequent applications of high-dose therapy (HDT)/autologous stem cell transplant (ASCT) changed the treatment paradigm for MM from extended dosing to an intensive strategy designed to eradicate the malignant cells in a single course of treatment. Although HDT-ASCT resulted in prolonged duration of remission and improved survival, the vast majority of patients still relapsed. Interferon (IFN) and glucocorticoid maintenance therapies demonstrated marginal improvements in outcomes but significant adverse effects. Novel agents introduced over the last decade have prolonged survival when given for maintenance following HDT-ASCT, but have also challenged the HDT-ASCT paradigm by achieving comparable remission rates when used alone as extended frontline therapy. This article reviews the evolution of therapeutic strategies for MM and discusses future questions facing MM investigators.

Secondary primary malignancies in multiple myeloma: an old NEMESIS revisited

The treatment of myeloma has undergone extraordinary improvements in the past half century. These advances have been accompanied by a concern for secondary primary malignancies (SPMs). It has been known for decades that extended therapy with alkylating chemotherapy agents, such as melphalan, carries an increased risk of therapy-related myelodysplastic syndrome and/or acute myeloid leukemia (t-MDS/AML), with a cumulative risk as high as 10–15%. High-dose chemotherapy with autologous stem cell support became widely accepted for myeloma in the 1990s. Despite the use of high doses of melphalan, the risk of t-MDS/AML with this procedure is estimated to be less than 5%, with much of this risk attributable to pretransplant therapy. Recently, lenalidomide has come under scrutiny for its possible association with SPMs. It is too soon to declare a causal relationship at this time, but there appears to be an increased number of SPMs in reports from several studies using lenalidomide maintenance. Current studies should be amended and future studies planned to better define the risk of SPMs and the risk factors and mechanisms for its development. Patients should be educated regarding this potential concern but the current use of lenalidomide should not generally be altered until further data are available.

Melphalan-prednisolone and vincristine-doxorubicin-dexamethasone chemotherapy followed by prednisolone/interferon maintenance therapy for multiple myeloma: Japan Clinical Oncology Group Study, JCOG0112

A multicenter phase III study for untreated multiple myeloma was conducted to investigate a switch-induction chemotherapy with melphalan-prednisolone and vincristine-doxorubicin-dexamethasone followed by randomization on maintenance therapy for patients achieving plateau. Between November 2002 and November 2005, 34 patients were registered. The study was closed early because of poor accrual. Thirty-three eligible patients, with a median age of 65 years (range: 47-77 years) were analyzed for the secondary purpose. For induction therapy, 16 patients were treated with vincristine-doxorubicin-dexamethasone and 17 with melphalan-prednisolone initially. In eight cases, induction therapy was switched because of a poor response. Both regimens were well tolerated, but neutropenia, anorexia, constipation and infection with neutropenia were more frequent for vincristine-doxorubicin-dexamethasone. Best response rates were 44% (95% confidence interval, 20-70) and 47% (95% confidence interval, 23-72), respectively, for vincristine-doxorubicin-dexamethasone and melphalan-prednisolone. Vincristine-doxorubicin-dexamethasone/melphalan-prednisolone switch-induction therapy might be feasible and effective for Japanese patients with multiple myeloma.

Total Therapy 3 for multiple myeloma: prognostic implications of cumulative dosing and premature discontinuation of VTD maintenance components, bortezomib, thalidomide, and dexamethasone, relevant to all phases of therapy

The impact of cumulative dosing and premature drug discontinuation (PMDD) of bortezomib (V), thalidomide (T), and dexamethasone (D) on overall survival (OS), event-free survival (EFS), time to next therapy, and post-relapse survival in Total Therapy 3 were examined, using time-dependent methodology, relevant to induction, peritransplantation, consolidation, and maintenance phases. Univariately, OS and EFS were longer in case higher doses were used of all agents during induction, consolidation (except T), and maintenance (except V and T). The favorable OS and EFS impact of D induction dosing provided the rationale for examining the expression of glucocorticoid receptor NR3C1, top-tertile levels of which significantly prolonged OS and EFS and rendered outcomes independent of D and T dosing, whereas T and D, but not V, dosing was critical to outcome improvement in the bottom-tertile NR3C1 setting. PMDD of V was an independent highly adverse feature for OS (hazard ratio = 6.44; P < .001), whereas PMDD of both T and D independently imparted shorter time to next therapy. The absence of adverse effects on postrelapse survival of dosing of any VTD components and indeed a benefit from V supports the use up-front of all active agents in a dose-dense and dose-intense fashion, as practiced in Total Therapy 3, toward maximizing myeloma survival.

The evolution and impact of therapy in multiple myeloma

Multiple myeloma is a clonal B-cell malignancy characterized by aberrant expression of plasma cells within the bone marrow, and is associated with the well known clinical manifestations anemia, bone disease, renal dysfunction, hypercalcemia, and recurrent infections. For many years, melphalan and prednisone represented the standard of care in multiple myeloma therapy, with stem cell transplantation reserved for selected patients. Treatment of the disease has evolved rapidly over the past decade, however, with the development and utilization of thalidomide, lenalidomide, and bortezomib. As a result of these developments, clinical outcomes have improved significantly. This review highlights important historic landmarks as well as more recent events that have played an important role in the evolution of myeloma therapy.

Relevant prognostic features of multiple myeloma and the new International Staging System

The new International Staging System should be reported in all future studies of multiple myeloma. However, the system fails to account for recent research findings pertaining to mechanisms of disease progression. This review describes development of the International Staging System and details prognostic factors that may further our understanding of the biology of multiple myeloma.

Phase II study of interleukin-12 for treatment of plateau phase multiple myeloma (E1A96): a trial of the Eastern Cooperative Oncology Group

The Eastern Cooperative Oncology Group (ECOG) conducted a phase II trial of interleukin-12 (IL-12) for plateau phase multiple myeloma. Patients were initially treated with IL-12 250 ng/kg I.V. daily for 5 days every 3 weeks. The trial was modified due to toxicity after the first 16 patients. IL-12 was given 300 ng/kg subcutaneously twice weekly for 24 weeks. Of 48 eligible patients, there were 4 objective responses (8.3%), all CR. The median survival and progression-free survival were 42.8 and 11.4 months. Unacceptable grade 3 or 4 non-hematologic toxicity (31% with IL-12 subcutaneously and 63% with IL-12 intravenously) was observed.

Maintenance therapy in multiple myeloma

Therapeutic advances in the treatment of multiple myeloma have significantly improved remission duration and overall survival (OS). These strategies have included the use of immunotherapy (interferon), novel agents (bortezomib, thalidomide, and lenalidomide), corticosteroids, and chemotherapy. While novel agents have had a major impact on response rates with initial therapy, most patients with multiple myeloma will eventually relapse. In the setting of minimal residual disease following standard dose or high-dose therapy, a number of different 'maintenance' strategies have emerged to prolong the duration of initial or subsequent remissions. The impact of these strategies on OS and event-free survival (EFS) is critically important, as the use of ineffective maintenance therapy adds the burden of additional cost, morbidity, and may reduce quality of life. Truly successful maintenance therapy will be effective in the setting of minimal residual disease, and will improve not only EFS, but also OS. This review summarizes the currently available data in the maintenance setting for multiple myeloma, and will discuss potential future trials to further address this important issue.

Treatment of newly diagnosed multiple myeloma based on Mayo Stratification of Myeloma and Risk-adapted Therapy (mSMART): consensus statement

Multiple myeloma is a neoplastic plasma cell dyscrasia that on a yearly basis affects nearly 17,000 individuals and kills more than 11,000. Although no cure exists, many effective treatments are available that prolong survival and improve the quality of life of patients with this disease. The purpose of this consensus is to offer a simplified, evidence-based algorithm of decision making for patients with newly diagnosed myeloma. In cases in which evidence is lacking, our team of 18 Mayo Clinic myeloma experts reached a consensus on what therapy could generally be recommended. The focal point of our strategy revolves around risk stratification. Although a multitude of risk factors have been identified throughout the years, including age, tumor burden, renal function, lactate dehydrogenase, beta2-microglobulin, and serum albumin, our group has now recognized and endorsed a genetic stratification and patient functional status for treatment.

Maintenance therapy for multiple myeloma with particular emphasis on thalidomide

Treatment standards are changing as a result of new findings in the therapy of multiple myeloma. So far, prednisone, dexamethasone and interferon-a have mainly been used as maintenance therapy after achieving remission or stable disease. At present, thalidomide is being considered as a new therapeutic option in several studies investigating maintenance therapy. As a result of the dose dependence of adverse effects such as neuropathy, constipation, sedation/vertigo and bradycardia, individual adjustment of the thalidomide dose is recommended. Only isolated cases of thrombosis occurred in the maintenance phase of therapy, and discontinuation of therapy is generally not necessary. While important study results on the efficacy of thalidomide following conventional chemotherapy are still awaited, it is the best documented drug so far for maintenance therapy following autologous stem cell transplantation. An upgrade of the response was seen in 22-73% of patients, as well as a significant prolongation of progression-free survival. For the first time, maintenance therapy with thalidomide showed a significant improvement in overall survival in a phase III study published recently. The tolerability of thalidomide could be further improved by including the option of intermittent administration of the drug.

Continuous prednisolone versus conventional prednisolone with VMCP-interferon-alpha2b as first-line chemotherapy in elderly patients with multiple myeloma

We report on a randomised trial that aimed to compare the efficacy of continued daily prednisolone treatment during the entire induction phase, with prednisolone given for 2 weeks of each cycle in combination with VMCP (vincristine, melphalan, cyclophosphamide, prednisolone)-interferon-alpha 2b (IFN-alpha 2b) treatment in 299 previously untreated elderly patients (median age: 67 years) with multiple myeloma. After completion of induction treatment patients were randomised to IFN-alpha 2b with or without prednisolone, thrice weekly. Response rate was 62% in the continuous and 60% in the control arm (intent to treat analysis, P=0.81). Progression-free survival [median: 20 months vs. 19 months; hazard ratio (HR): 0.99, 95% confidence interval (CI): 0.74-1.33, P=0.97] and overall survival (median: 34 months vs. 37 months; HR: 1.16, 95% CI: 0.85-1.59, P=0.35) were similar in both groups. Reduced performance status (Eastern Cooperative Oncology Group, grades 2-4) was the predominant risk factor for poor survival followed by age >65 years, high beta2-microglobulin, and impaired renal function. There was more grades 3-4 dyspnoea and cardiac impairment and grades 1-2 hyperglycaemia, but less nausea, emesis and anaemia in patients on continuous prednisolone therapy. In conclusion, continuing prednisolone treatment during the entire duration of the induction phase with VMCP-IFN-alpha 2b did not improve outcome.

Sequential, cycling maintenance therapy for post transplant multiple myeloma

High-dose chemotherapy with autologous stem cell transplantation in patients with newly diagnosed multiple myeloma can prolong survival but is not curative. Maintenance therapy post transplant may prolong the disease-free interval and impact overall survival. We have conducted a phase II pilot study of 28 post transplant myeloma patients treated with a sequential, cycling maintenance regimen. The regimen was designed to include a variety of active myeloma agents chosen for ease of administration to enhance patient compliance and scheduled sequentially to minimize toxicity. The 12-month cycling schedule included dexamethasone (months 1-3); melphalan and prednisone (months 4, 5); cyclophosphamide and prednisone (months 6, 7); alpha-interferon (months 8-10); followed by a drug holiday (months 11, 12). The regimen was generally well tolerated with five patients developing reversible grade III-IV toxicity (diabetes-induced hyperglycemia in four, neutropenia in one). There was one toxic death on study due to non-neutropenic pneumonia and sepsis. Median event-free survival from transplant was 36.9 months (95% CI 23.6 - upper limit not yet reached) with median overall survival not yet reached at a median follow-up of 44 months. This concept of cycling, sequential maintenance with various agents, perhaps including newer biological, targeted agents, warrants further investigation in multiple myeloma.

Pilot study of 13cis-retinoic acid+dexamethasone+alpha interferon as maintenance therapy following high-dose chemotherapy and autologous stem cell transplant for multiple myeloma

Interleukin 6 (IL-6) is a major growth factor for myeloma cells and retinoids have been shown to inhibit expression of the interleukin 6 receptor (IL-6R). We performed a pilot study to assess the efficacy and tolerability of 13cis retinoic acid (13cRA) and dexamethasone (Dex), when added to interferon alpha (IFNalpha) as maintenance therapy post autologous stem cell transplantation. Between 90 and 120 days post stem cell transplantation, 33 patients were started on 13cRA 1 mg/kg p.o. daily for 14 days and Dex 40 mg p.o daily for 5 days every month. 13cRA was dose escalated by 0.5 mg/kg/month to 2 mg/kg. Seventeen patients had a persistent paraprotein post transplant. Overall, a response to therapy was observed in 11/17 (64%), with a complete response in 4/17 (23.5%) and a partial response (>/=50% paraprotein decline) in 7/17 (41%). With a median follow-up of 34.8 months, 22/33 (66%) demonstrated disease progression and 11/33 (33%) died. The median progression-free survival from diagnosis was 34.7 months. Although a decline in paraprotein was frequently observed on triple therapy, many patients discontinued therapy due to the side-effects of the IFNalpha. Future trials should be designed using 13cRA and Dex alone.

Phase III study of ranimustine, cyclophosphamide, vincristine, melphalan, and prednisolone (MCNU-COP/MP) versus modified COP/MP in multiple myeloma: a Japan clinical oncology group study, JCOG 9301

To investigate whether combination chemotherapy with vincristine, cyclophosphamide, prednisolone, and melphalan (COP/ MP) with the addition of ranimustine (MCNU) (MCNU-COP/MP) is superior to the slightly modified COP/MP (mCOP/MP) regimen in multiple myeloma (MM), a multicenter randomized study was performed. Two hundred ten patients with newly diagnosed, overt MM not treated with chemotherapy were enrolled from 32 institutions of the Lymphoma Study Group of the Japan Clinical Oncology Group and were randomized to receive either MCNU-COP/MP or mCOP/MP. The response rate (RR) to mCOP/MP was 43.7% (95% confidence interval [CI], 33.9%-53.8%] and to MCNU-COP/MP was 56.1% (95% CI, 46.1%-65.7%) (P = .097). The progression-free survival (PFS) was significantly longer for patients treated with MCNU-COP/MP than for patients treated with mCOP/MP (median, 23.0 months [95% CI, 18.9-25.8] versus 15.8 months [95% CI, 14.1-19.4]) (P = .014). However, no significant difference in overall survival rate (OS) was observed between the groups (median, 49.9 months [95% CI, 40.4-59.1] versus 44.0 months [95%, CI, 32.8-59.8]) (P = .75). Grades 3 and 4 hematological toxicities were more frequently observed with MCNU-COP/MP than with mCOP/MP, but the incidence of grades 3 and 4 nonhematological toxicities was low in both groups. In conclusion, MCNU-COP/MP in comparison with mCOP/MP improved RR and PFS in overt MM; however, this outcome did not contribute to prolonging OS, indicating that addition of MCNU to mCOP/MP has no benefit on survival.

Therapy strategies for multiple myeloma: current status

Multiple myeloma (MM) is characterized by infiltration of bone marrow with a clone of neoplastic plasma cells. Impaired hematopoiesis and reduced production of functional immunoglobulins, as well as the induction of pathognomonic osteolytic lesions primarily contribute to the morbidity of patients with MM. Conventional chemotherapy is the treatment of choice for older patients, whereas those under 60 years benefit significantly from high-dose therapy followed by stem-cell rescue. The use of tandem transplantation, developed to further escalate the conditioning dose, has achieved additional improvement in survival. Interferon-alpha and glucocorticoids are effective as maintenance measures in MM but remain controversial because of their associated high costs and considerable toxicity. The resurrection of an old drug, thalidomide, for the therapy of MM and the development of potent immunomodulatory derivatives are highly promising new treatments that target MM cell-host interactions and the bone-marrow microenvironment, as well as the myeloma cell itself. The importance of the use of bisphosphonates for the prevention or amelioration of skeletal complications and hypercalcemia is well established. New generations of bisphosphonates show potent antitumor activity, again emphasising the importance of targeting the microenvironment of the plasma-cell clone.

A new staging system for multiple myeloma patients based on the Southwest Oncology Group (SWOG) experience

We aimed to develop and evaluate a staging system for multiple myeloma (MM) based on easily obtained laboratory measures. The Durie-Salmon stage is most commonly used and is an effective system of patient stratification for clinical trial research. However, the criteria are complex and many laboratory parameters are required to properly stage patients. In this analysis, we focused on two common measures with prognostic importance in MM: serum beta2 microglobulin (beta2m) and serum albumin. Pre-study data on 1555 previously untreated MM patients enrolled on four recent South-west Oncology Group (SWOG) phase III trials were used in the analysis. Staging models were developed and validated using regression tree methods for survival outcomes. SWOG stages were defined as: stage 1, beta2m < 2.5 mg/l (14% of patients, median overall survival of 55 months); stage 2, 2.5 </= beta2m < 5.5 (43% of patients, median overall survival of 40 months); stage 3, beta2m >/= 5.5 and albumin >/= 30 g/l (32% of patients, median overall survival of 24 months); and stage 4, beta2m >/= 5.5 and albumin < 30 g/l (11% of patients and median overall survival of 16 months). This staging scheme was also predictive of event-free survival, first-year mortality and long-term (>/= 5 years) event-free survival. We conclude that although the SWOG stage does not represent a new prognostic marker for MM (cytogenetics, FISH), it could provide a simple alternative to the Durie-Salmon stage for patients with previously untreated MM. Additional evaluation in other MM patient populations is needed to confirm results.

A review of the cytokine network in multiple myeloma: diagnostic, prognostic, and therapeutic implications

Because many studies have focused on growth factors in multiple myeloma, the study of the cytokine network appears to be useful for this purpose. Interleukin-6 (IL-6) and IL-2 with their soluble receptors (IL-3, IL-4, IL-10, and IL-11) have been examined. Plasma cells may produce IL-6 by an autocrine mechanism whereas a paracrine mechanism is believed to be involved in the production of IL-6 by bone marrow stromal cells through an interaction between adhesion molecules present on myeloma plasma cells and their respective receptors that are present on bone marrow stromal cells. In addition, control over production of IL-6 may be exerted by other ILs such as IL-1beta and IL-10. Among target cells, the growth of normal and myeloma plasma cells is supported by IL-6, which also induces the differentiation of myeloma plasmablastic cells into mature plasma cells. This last action also is shared by IL-3, IL-4, and, most likely, IL-8. Evaluation of the serum level of IL-6, C reactive protein, soluble IL-6 receptor (sIL-6R), and soluble IL-2 receptor (sIL-2R), together with the activity exerted by IL-3 and IL-4 on some cellular subsets, may constitute an additional element in the differential diagnosis of borderline cases. However, the concomitant evaluation of all immunologic parameters could be more useful than the value of a single IL. Serum levels of IL-6, sIL-6R, sIL-2R, and the expression of membrane-bound IL-2 receptors, both on bone marrow plasma cells and on peripheral blood mononuclear cells, are correlated with disease activity and disease stage. In addition, IL-6 and sIL-6R serum levels are believed to be correlated with the duration of disease-free survival because a high serum level at the time of diagnosis is believed to be correlated with a short duration of survival. However, some laboratory parameters may express the same prognostic value as high beta(2) microglobulin and lactate dehydrogenase (LDH) serum levels together with a high plasma cell labeling index are correlated with disease activity. Furthermore, if the evaluation is performed at the time of diagnosis, high values of these parameters are correlated with a short disease-free survival. A correlation between laboratory parameters and the serum level of several cytokines was demonstrated. Hence, the real advantage of the prognostic evaluation of cytokines is reserved for patients who do not exhibit uniform results with regard to beta(2) microglobulin and LDH serum levels, or, better, for borderline cases. With regard to the differential diagnosis, all immunologic parameters should be evaluated concomitantly rather than separately to confer a real prognostic value to results. Furthermore, a particular relation was found between a high sIL-6R serum level and a poor response to chemotherapy, therefore suggesting the possibility of identifying in advance a subset of patients with a high risk of treatment failure, as has already been demonstrated in other hematologic malignancies.Finally, the majority of studies indicate that interferons are used mainly in the immunotherapy for multiple myeloma, whereas many clinical trials should still be required for the evaluation of the effectiveness of anti-I-L6 antibodies or antiidiotypic vaccines in reference to the eligible patients for these particular therapies.

[Interferons and hematology]

BACKGROUND

IFN alpha are cytokines used for a number of years in the treatment of certain hemopathies, i.e. of a myeloid and lymphoid etiology. IFN alpha are a family of polypeptides produced by eukaryote cells in response to various stimulant agents. The first trials using this cytokine in humans were carried out by H. Strander in the years 1965-1970. IFN alpha contain anti-viral, anti-proliferative and immunomodulatory properties. The access of clinicians to IFN alpha molecules, in addition to elements produced by genetic engineering for approximately the past 20 years, has permitted a number of therapeutic trials to be carried out. In hematology the clinical interest of IFN alpha was primarily in chronic myeloid and lymphoid proliferating syndromes. Certain indications have to date been well demonstrated. However, the impact of IFN alpha on therapeutic care of certain hemopathies as compared to conventional treatment remains controversial. At the same time, the frequency of side effects from treatment with IFN alpha and its cost should be taken into consideration.

CURRENT POSITION AND MAJOR POINTS

The therapeutic trials carried out over the past ten years have proven the interest of IFN alpha in, essentially, two diseases: on one hand chronic myeloid leukemia with the acquisition of cytogenetic remission and on the other malignant non-Hodgkin's follicular type lymphoma. However, as regards other hemopathies the place of IFN alpha remains debatable.

PERSPECTIVES

The future of IFN alpha use in the treatment of hemopathies appears to be linked to its association with new treatments, an association, however, where its efficacy and superiority should be demonstrated. This is the case in chronic myeloid leukemia where IFN alpha could be associated with aracytine or the inhibitors of tyrosine kinase. Also, in the treatment of malignant non-Hodgkin's lymphomas as well as the studies concerning the association between IFN alpha and monoclonal antibodies, in particular antibody anti-CD 20.

Management of multiple myeloma

There has been no improvement in the treatment of multiple myeloma (MM) during the last decades and two meta-analyses of randomized trials recorded no significant survival benefit for combination chemotherapy compared to the classic melphalan-prednisone combination. However the past 15 years has seen several innovative strategies which have dramatically modified the management of MM. In younger patients, high-dose therapy with autologous stem cell transplantation is considered to be superior to conventional chemotherapy and is used as part of front-line therapy. A number of issues have been addressed in recent trials in order to improve the results of autologous transplantation (source of stem cells, conditioning regimen, impact of double transplants, maintenance therapy). Bisphosphonates reduce the incidence of skeletal-related events and improve the quality of life. Recombinant erythropoietin reduces red blood cell transfusion need and improves the quality of life. Thalidomide has been introduced more recently. Phase II studies with thalidomide alone or combined with dexamethasone have shown impressive response rates and this drug is currently being evaluated as part of front-line therapy. Finally, analysis of prognostic factors such as beta 2 microglobulin and cytogenetics define subgroups of patients with a completely different outcome and help the process of selecting therapeutics strategies.

Current therapy for multiple myeloma

Multiple myeloma is an incurable plasma cell malignancy that accounts for 10% of all hematologic cancers. For decades the mainstay of therapy has been the use of melphalan and prednisone; with this regimen, the median survival is approximately 3 years. Recently, important advances were made that have substantially altered the manner in which patients with myeloma are treated. Newly diagnosed patients with good performance status are now treated with autologous stem cell transplantation, resulting in improved survival. Because of the increasing use of transplantation as initial therapy, several therapeutic issues have emerged: the role of tandem transplantation, early vs delayed transplantation, and the role of allogeneic transplantation. The pronounced activity of thalidomide in patients with refractory myeloma represents another important advance. This has prompted the study of several novel agents in the treatment of myeloma, at least 2 of which appear promising. Supportive care measures also have improved, including the use of bisphosphonates to prevent osteolytic lesions. The purpose of this review is to summarize recent advances and provide an evidence-based approach to the treatment of multiple myeloma.

Newly diagnosed multiple myeloma

Melphalan combined with prednisone (MP) has been accepted as the standard therapy for previously untreated multiple myeloma (MM) because most studies demonstrate only a modest survival benefit of combination chemotherapy regimens when compared with MP. There have been modest gains with more intensive myeloablative regimens in combination with blood stem cell support, particularly for patients with early primary refractory disease who subsequently achieve partial remission, and for the approximately 25% to 35% of patients achieving complete remission. To preserve the ability to adequately collect stem cells, the use of alkylating agents, such as melphalan, should be limited in the previously untreated patient with myeloma (including those older than 65 years of age) who is a candidate for myeloablative therapy. Pulse dexamethasone-containing regimens provide rapid responses and may be considered the first regimens of choice. Although vincristine/doxorubicin/dexamethasone (VAD) produces responses in approximately 50% to 70% of patients with previously untreated multiple myeloma, use early in the disease has not improved survival. Outside of a specific study protocol, this regimen may be best reserved for patients with refractory (particularly relapsing) disease. Notable exceptions include patients with renal failure or plasma cell leukemia in whom the rapid responses provided by VAD may avoid potentially permanent, serious complications. Recently, new agents with novel mechanisms of action (ie, thalidomide, immunomodulatory drugs, proteosome inhibitors) have demonstrated activity in resistant myeloma. Because these agents are likely to show activity alone or in combination, newly diagnosed patients and previously untreated patients should be considered for clinical trials. Thalidomide/dexamethasone has already produced response rates of 65% to 75% in previously untreated patients. Its ease of administration along with stem cell preservation are likely to make this, followed by myeloablative therapy with stem cell support, the treatment of choice for untreated myeloma as confirmatory studies are completed.

Maintenance therapy with alternate-day prednisone improves survival in multiple myeloma patients

The role of maintenance therapy in multiple myeloma is controversial. Recent studies have shown an improvement in both progression-free and overall survival for patients receiving maintenance treatment with a combination of interferon and glucocorticoids, compared with interferon alone. The role of glucocorticoids alone as maintenance therapy has not been previously addressed. We compared alternate-day, oral prednisone at 2 different dose levels (10 mg versus 50 mg) for remission maintenance among previously untreated myeloma patients following a response to induction with standard-dose vincristine, doxorubicin, and dexamethasone with prednisone (VAD-P) or VAD-P plus quinine (VAD-P/Q). There were 250 eligible patients registered on Southwest Oncology Group study 9210 and randomized to receive VAD-P or VAD-P/Q. There were 125 patients achieving at least a 25% tumor reduction following induction therapy who were randomized to either physiologic (10 mg) or pharmacologic (50 mg) doses of alternate-day, oral prednisone until disease progression. At the time of study entry, patient characteristics were similar in VAD-P and VAD-P/Q patients and in the 2 arms randomized to maintenance therapy. After a median follow-up of 53 months, there was no difference in either progression-free or overall survival between the 2 induction regimens. However, from the time of maintenance randomization, both progression-free (14 versus 5 months; P =.003) and overall survival (37 versus 26 months; P =.05) were significantly improved in patients receiving 50 mg as compared with 10 mg alternate-day prednisone. There was no difference in treatment-related adverse events between the groups. Thus, 50 mg, oral, alternate-day prednisone is effective maintenance treatment for multiple myeloma patients who achieve a response to induction chemotherapy. (Blood. 2002;99:3163-3168)

Interleukin-6 and the network of several cytokines in multiple myeloma: an overview of clinical and experimental data

Study of the network of cytokines has helped identify cell growth factors in multiple myeloma. Plasma cells themselves may produce autocrine interleukin 6 (IL-6) while IL-6 production by bone marrow stromal cells may operate a paracrine mechanism. Involvement of IL-6 in multiple myeloma is indicated by its ability to induce the differentiation of myeloma plasmablasts into mature malignant plasma cells. Differential diagnosis between multiple myeloma and monoclonal gammopathies of undetermined significance (MGUS) is generally based on clinical and laboratory parameters. Nevertheless, evaluation of the serum level of IL-6, C reactive protein, soluble IL-6 receptor, soluble IL-2 receptor together with the activity exerted by IL-3 and IL-4 on some cellular subsets constitutes an additional element in the differential diagnosis of border-line cases. Serum levels of IL-6, soluble IL-6 receptor (sIL-6R), soluble interleukin-2 receptor (sIL-2R) and the expression of membrane-bound IL-2 receptors, both on bone marrow plasma cells and on peripheral blood mononuclear cells are correlated with disease activity and disease stage. In addition, IL-6 and sIL-6R serum levels correlate with the duration of survival, as high values at the time of diagnosis correlate with short duration of survival.

Monoclonal antibody identifies a distinctive epitope expressed by human multiple myeloma cells

Employing a technology called differential immunization for antigen and antibody discovery (DIAAD), we aimed to generate monoclonal antibodies (mAbs) specific to human multiple myeloma (MM) cells. The fundamental principles of DIAAD rely on the induction of high zone tolerance to the "wild type" (normal) antigen. followed by immunization with the modified (diseased) antigen. Because chronic myelogenic leukemia (CML) cells are derived from a lineage closely related to MM, we immunized mice by contrasting a pool of MM cells with CML cells. Monoclonal antibody VAC69 reacted exclusively with MM cells, identifying a membrane molecule composed of a single-chain glycoprotein with a molecular weight of 78-120 kd. This antigen exhibited narrow tissue specificity and was not found on human cancers such as prostate, breast, or cervical carcinoma; leukemia; or lymphoma, nor was it seen on normal human peripheral lymphocytes or on Epstein-Barr virus-transformed B-cell lines. By immunohistochemistry, mAb VAC69 showed no binding to antigens expressed on normal human ovary, breast, prostate, lung or colon tissue, nor did it bind to human breast or prostate cancer. Conversely, mAb VAC69 bound strongly to human MM, although showing only slight binding to histiocytes or inflamed cells in human lymph nodes and human tumors of the colon, lung, and ovary. Monoclonal antibody VAC69 also triggered cancer-specific cytotoxicity in vitro (in the presence of complement) as well as in vivo using a sever combined immunodeficiency model transplanted with human MM. Further studies showed the ability of mAb VAC69 to be specifically internalized by human MM cells, indicating its potential use for therapeutic intervention in MM by delivering drugs into cancer cells.

Standard-dose therapy for multiple myeloma: The Southwest Oncology Group experience

We summarize the Southwest Oncology Group (SWOG) experience with standard therapy for multiple myeloma by reviewing and updating data from seven consecutive SWOG trials. Some modest progress has been made since the introduction of melphalan and prednisone (MP) for induction therapy, using regimens that involve vincristine and doxorubicin, and which save alkylating agents for possible later high-dose therapy. For maintenance, it appears that prednisone plays a useful role. We demonstrate the use of the data collected in these trials with a proposed new staging system.

Randomized trial of alpha-interferon or dexamethasone as maintenance treatment for multiple myeloma

In order to assess the role of alpha-interferon or dexamethasone as maintenance therapy for multiple myeloma, 172 consecutive, previously untreated patients with disease of low or intermediate tumor mass received primary therapy with oral melphalan and intermittent, high-dose dexamethasone (MD), repeated monthly. Within 5 months, 84 responding patients were assigned at random to maintenance treatment with alpha-interferon (3 mU s.c. 3 x weekly) or dexamethasone (20 mg/m2 p.o. each morning for 4 days) repeated monthly until relapse. Upon relapse, MD was resumed for 2 cycles and second responses were maintained with 4-day courses of melphalan-dexamethasone until second relapse. Initial response was achieved in 88 patients (51%) after a median 0.7 month and no more than 3 courses of MD, a frequency of response similar to that observed previously with dexamethasone alone. There were identical median remissions of 10 months with interferon or dexamethasone, both maintenance regimens being associated with infrequent, mild, and reversible side effects. Significantly more patients responded again to resumption of MD after disease relapse to interferon (82%) than to dexamethasone (44%) (P = 0.001). The median remission from randomization to melphalan-resistant second relapse was 32 months for patients maintained initially on interferon compared to 19 months for those on dexamethasone (P = 0.01). These findings supported an advantage for interferon in remission maintenance by increasing the frequency of tumor recontrol with later treatment that included dexamethasone.

Viewpoint on the impact of interferon in the treatment of multiple myeloma: benefit for a small proportion of patients?

Interferon-alpha (IFN-alpha) generally inhibits myeloma cell growth. However, a growth stimulatory effect for myeloma cells has also been reported. In patients with untreated multiple myeloma (MM) IFN-alpha, used as a single agent, produced an objective response rate ranging from 10 to 25%. In previously untreated patients: (1) the time to response is short, (2) the median duration of response is similar to the duration of response observed in patients given chemotherapy, and (3) the patients who are more likely to benefit are those with IgA myeloma type. Concerning the results of IFN-alpha given as a single agent in relapsing and resistant MM, they are poor, with a response rate ranging between 10-20%. The combination of high-dose glucocorticoids and IFN-alpha for relapsing/resistant patients produced controversial results. Some studies showed an increased response rate and/or longer survival with chemotherapy plus IFN-alpha versus chemotherapy alone in previously untreated patients. In contrast, most reports did not show a significant increase in response rate or survival benefit by adding IFN-alpha to the initial chemotherapy. Perhaps the most encouraging role for IFN in MM is as maintenance therapy in patients responding to first line treatment (ie conventional chemotherapy followed or not by high-dose intensification/autotransplantation). In spite of that, several reports failed to show longer response duration. The majority of studies have shown a modest but significant prolongation in response duration in favour of the IFN arm. However, most of these studies have failed to show a significant survival advantage with IFN maintenance. A meta-analysis, by the Myeloma Trialists' Collaborative Group in Oxford, based on the individual data from 4012 patients included in 24 randomized trials (induction and/or maintenance) has shown that IFN produced a moderate improvement in relapse-free survival and a minor improvement in overall survival. In summary, the only role of IFN in MM is as maintenance treatment after a response is achieved. However, looking at the published data, it seems that the vast majority of patients do not benefit from IFN maintenance, while a small proportion of them, in the range of 5-10%, obtain a significant prolongation in event-free survival and overall survival. Unfortunately, there are no predictive factors that can identify the patients who are likely to benefit from IFN maintenance.

Idiotype Vaccination in Human Myeloma: Generation of Tumor-Specific Immune Responses After High-Dose Chemotherapy

Igs contain unique portions, collectively termed idiotypes (Id), that can be recognized by the immune system. Id expressed by tumor cells in B-cell malignancies can be regarded as tumor-specific antigens and a target for vaccine immunotherapy. We have started a vaccination trial in multiple myeloma (MM) using Id-specific proteins conjugated to keyhole limpet hemocyanin (KLH) as immunogens and low doses of subcutaneous granulocyte-macrophage colony-stimulating factor (GM-CSF) or interleukin-2 (IL-2) as immunoadjuvants. Twelve patients who had previously been treated with high-dose chemotherapy followed by peripheral blood progenitor cell (PBPC) transplantation entered this study from August 1995 to January 1998. All patients were in first remission at the time of vaccination. They received subcutaneous injections of Id vaccines and immunoadjuvants in an outpatient setting. The generation of Id-specific T-cell proliferative responses was documented in 2 patients, whereas a positive Id-specific delayed-type hypersensitivity (DTH) reaction was observed in 8 of the 10 patients studied. DTH specificity was confirmed in 1 patient by investigating the reactivity to synthetic peptides derived from the VDJ sequence of the tumor-specific Ig heavy chain. None of the patients generated soluble immune responses to Id, whereas the generation of soluble and cellular immune responses to KLH was observed in 100% and 80%, respectively. Eleven patients completed the treatment, whereas 1 patient failed to finish owing to progression of disease. Freedom from disease progression (FFDP), measured from the date of first Id/KLH injection to the date of first treatment after vaccination or last follow-up, ranged from 9 to 36 months. These data indicate that the immune competence status of MM patients is still susceptible to specific immunization after high-dose chemotherapy and PBPC transplantation. It remains to be determined whether generation of Id-specific immune responses can reduce the relapse rate of patients with minimal residual disease.

Idiotype Vaccination in Human Myeloma: Generation of Tumor-Specific Immune Responses After High-Dose Chemotherapy

Igs contain unique portions, collectively termed idiotypes (Id), that can be recognized by the immune system. Id expressed by tumor cells in B-cell malignancies can be regarded as tumor-specific antigens and a target for vaccine immunotherapy. We have started a vaccination trial in multiple myeloma (MM) using Id-specific proteins conjugated to keyhole limpet hemocyanin (KLH) as immunogens and low doses of subcutaneous granulocyte-macrophage colony-stimulating factor (GM-CSF) or interleukin-2 (IL-2) as immunoadjuvants. Twelve patients who had previously been treated with high-dose chemotherapy followed by peripheral blood progenitor cell (PBPC) transplantation entered this study from August 1995 to January 1998. All patients were in first remission at the time of vaccination. They received subcutaneous injections of Id vaccines and immunoadjuvants in an outpatient setting. The generation of Id-specific T-cell proliferative responses was documented in 2 patients, whereas a positive Id-specific delayed-type hypersensitivity (DTH) reaction was observed in 8 of the 10 patients studied. DTH specificity was confirmed in 1 patient by investigating the reactivity to synthetic peptides derived from the VDJ sequence of the tumor-specific Ig heavy chain. None of the patients generated soluble immune responses to Id, whereas the generation of soluble and cellular immune responses to KLH was observed in 100% and 80%, respectively. Eleven patients completed the treatment, whereas 1 patient failed to finish owing to progression of disease. Freedom from disease progression (FFDP), measured from the date of first Id/KLH injection to the date of first treatment after vaccination or last follow-up, ranged from 9 to 36 months. These data indicate that the immune competence status of MM patients is still susceptible to specific immunization after high-dose chemotherapy and PBPC transplantation. It remains to be determined whether generation of Id-specific immune responses can reduce the relapse rate of patients with minimal residual disease.