Randomized trial of interferon maintenance in multiple myeloma: a study of the National Cancer Institute of Canada Clinical Trials Group

Safety of lenalidomide for maintenance treatment of patients with multiple myeloma following autologous stem cell transplantation

INTRODUCTION

Myeloma is the second most common hematological cancer, with 5800 cases per year diagnosed in the UK. Despite improved treatment it is still considered non-curable, although the median survival has increased from 3 to 8 years over the past 20 years. Treatment involves the use of induction therapy and consolidation with autologous stem cell transplant (ASCT) in patients deemed fit enough. Further attempts to improve outcomes include the use of maintenance therapy.

AREAS COVERED

This review details all trials in which lenalidomide has been used as maintenance following ASCT. PubMed searches included randomized control trials, observational cohort, reviews, and meta-analysis.

EXPERT OPINION

Lenalidomide is a well-tolerated, oral agent that is associated with increased overall and progression free survival when used as maintenance following ASCT. Its use in this setting is FDA and EMA approved and is standard of care in Europe and North America. The early link between lenalidomide and second hematological cancers appears to be associated with use in combination with melphalan. There is an increase in non-melanoma skin cancers and solid tumors in the elderly but this has minimal impact on mortality. Lenalidomide use as part of combination maintenance is underway and may further improve outcomes.

Clinical Efficacy of a Novel Therapeutic Principle, Anakoinosis

Classic tumor therapy, consisting of cytotoxic agents and/or targeted therapy, has not overcome therapeutic limitations like poor risk genetic parameters, genetic heterogeneity at different metastatic sites or the problem of undruggable targets. Here we summarize data and trials principally following a completely different treatment concept tackling systems biologic processes: the principle of communicative reprogramming of tumor tissues, i.e., anakoinosis (ancient greek for communication), aims at establishing novel communicative behavior of tumor tissue, the hosting organ and organism via re-modeling gene expression, thus recovering differentiation, and apoptosis competence leading to cancer control - in contrast to an immediate, "poisoning" with maximal tolerable doses of targeted or cytotoxic therapies. Therefore, we introduce the term "Master modulators" for drugs or drug combinations promoting evolutionary processes or regulating homeostatic pathways. These "master modulators" comprise a broad diversity of drugs, characterized by the capacity for reprogramming tumor tissues, i.e., transcriptional modulators, metronomic low-dose chemotherapy, epigenetically modifying agents, protein binding pro-anakoinotic drugs, such as COX-2 inhibitors, IMiDs etc., or for example differentiation inducing therapies. Data on 97 anakoinosis inducing schedules indicate a favorable toxicity profile: The combined administration of master modulators, frequently (with poor or no monoactivity) may even induce continuous complete remission in refractory metastatic neoplasia, irrespectively of the tumor type. That means recessive components of the tumor, successively developing during tumor ontogenesis, are accessible by regulatory active drug combinations in a therapeutically meaningful way. Drug selection is now dependent on situative systems characteristics, to less extent histology dependent. To sum up, anakoinosis represents a new substantive therapy principle besides novel targeted therapies.

Multiple Myeloma, Version 2.2016: Clinical Practice Guidelines in Oncology

Multiple myeloma (MM) is a malignant neoplasm of plasma cells that accumulate in bone marrow, leading to bone destruction and marrow failure. Recent statistics from the American Cancer Society indicate that the incidence of MM is increasing. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) included in this issue address management of patients with solitary plasmacytoma and newly diagnosed MM.

Multiple myeloma: an update of developments in targeted therapy

Multiple myeloma continues to be an incurable illness. Improvement in our understanding of the disease is leading to new therapeutic modalities and the definition of new targeted therapy. Several pathways have been identified as areas for targeted therapy, and this review will discuss key molecules in some detail. New agents and molecules with biologic modulator activity appear to be changing the natural history of the disease. Agents such as thalidomide or its analogs, arsenic trioxide or bortezomib, hold great promise; however, much is yet to be learned on how to integrate these agents into disease management.

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.

Lenalidomide plus melphalan without prednisone for previously untreated older patients with multiple myeloma: a phase II trial

BACKGROUND

We conducted a phase II trial that evaluated the tolerability and efficacy of combining lenalidomide with melphalan in previously untreated patients with multiple myeloma who were not candidates for autologous stem cell transplantation.

METHODS

After a run-in phase of 6 patients, we planned to conduct a randomized phase II selection-design trial that assessed 2 dose levels of lenalidomide, given days 1 to 21, combined with melphalan, given days 1 to 4, and every 28 days. Planned doses of melphalan were 9 mg/m(2)/d and respective doses of lenalidomide were 10 and 20 mg/d (M9L10 and M9L20). Coprimary endpoints were the frequency of dose-limiting Planned doses of melphalan were 9 mg/m(2)/d and respective doses of lenalidomide were 10 and 20 mg/d (M9L10 and M9L20). toxicities (DLT) and complete response (CR).

RESULTS

Four patients received M9L10; all experienced DLTs, which resulted in closure of this cohort. When using the same schedule, we then sequentially tested M6L10 (melphalan 6 mg/m(2) on days 1 to 4 and lenalidomide 10 mg/d on days 1 to 21 every 28 days) (6 patients), M4L15 (melphalan 4 mg/m(2) on days 1 to 4 and lenalidomide 15 mg/d on days 1 to 21 every 28 days) (6 patients), and M5L10 (melphalan 5 mg/m(2) days 1 to 4 and lenalidomide 10 mg/d days 1 to 21 every 28 days) (34 patients). In each cohort, the DLT endpoint was reached because of severe and prolonged hematologic toxicity. At the final dose level, M5L10, 20 of 27 patients experienced DLTs within their first 3 cycles; among 10 patients who received at least 6 cycles, none achieved a CR.

CONCLUSIONS

Combining lenalidomide plus melphalan without prednisone is associated with substantial hematologic toxicity that precludes cyclical administration of adequate drug doses.

The role of natural killer cells in immunity against multiple myeloma

Multiple myeloma (MM) is an essentially incurable malignancy associated with profound immune dysregulation. Despite the advent of novel therapies and improvements in survival over the last 10 years, death from progressive disease and infection remains a common outcome. Natural killer (NK) cells are CD56(+)CD3(-) large granular lymphocytes that constitute a key cellular subset of the innate immune system. For over 30 years, the relationship between NK cells and MM has been described in the clinical setting and characterized in the laboratory. Data suggest that NK cells may play a role in the immune response to MM; however, this effect is lost due to immunoevasive strategies utilized by MM. Nevertheless, progress in the understanding of the mechanisms perpetuating this effect have led to new opportunities to recover or augment NK cell function therapeutically in MM. In fact, the novel agents thalidomide, lenalidomide and bortezomib all confer anti-MM effects, in part, through enhancement of NK cell function. Currently, the development of therapies designed specifically to increase NK cell cytotoxicity against MM is under way. The present review summarizes the current understanding of the NK cell versus MM effect and characterizes therapeutic interventions that exert anti-MM efficacy via NK cell function against the disease.

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.

[New therapeutic strategies for multiple myeloma. Efficacy and cost-effectiveness analyses]

The objective of the present article is the review of the most important therapeutic innovations in the treatment of multiple myeloma in terms of efficacy and cost-effectiveness. Besides autologous transplant with peripheral-blood stem-cell, thalidomide establishes as one of the most powerful therapeutic tools in induction and maintenance treatment and together with lenalidomide and bortezomib as therapy for relapsing/refractory multiple myeloma. Considering, the last named situation thalidomide can be an adequate therapeutical option in combination with dexamethasone. Under a strictly pharmacoeconomic point of view, lenalidomide and bortezomib seem to be additional alternatives in patients previously treated with thalidomide.

Clinically relevant end points and new drug approvals for myeloma

This manuscript summarizes the recommendations of the American Society of Hematology/US Food and Drug Administration Workshop on Clinical Endpoints in Multiple Myeloma, which brought together clinical investigators in multiple myeloma, the United States Food and Drug Administration, pharmaceutical companies, patient advocates and other concerned scientists and physicians to provide guidance, consensus and consistency in the definition of clinically relevant end points to expedite new drug approvals for multiple myeloma in the appropriate trial design settings. This manuscript will therefore be a most valuable resource to provide the framework for the design of appropriate clinical trial strategies for more rapid new drug approval in myeloma.

An open, randomized, controlled, phase II, single centre, two-period cross-over study to compare the quality of life and toxicity experienced on PEG interferon with interferon-α2b in patients with multiple myeloma maintained on a steady dose of interferon-α2b

PURPOSE

To compare the effects of pegylated interferon-alpha2b (P-IFN) and interferon-alpha2b (IFN) on quality of life (QoL) and toxicity in patients with multiple myeloma maintained on a steady dose of IFN.

PATIENTS AND METHODS

Consenting, eligible myeloma patients on IFN maintenance therapy for at least 6 weeks were randomly (1:1) allocated to receive P-IFN for 3 months followed by IFN for 3 months, or to continue with IFN for 3 months followed by P-IFN for 3 months (cross-over design). Patients were assessed for toxicity and QoL. Dose of P-IFN was equivalent to IFN.

RESULTS

The study enrolled 60 patients. At enrollment, 35 patients were in complete remission, 20 in partial remission and 5 were minimal responders. P-IFN was associated with significantly better global QoL score (mean difference 8.4; P = 0.0002). There was a significant improvement in functional scales--physical (P = 0.03), emotional (P = 0.04), social (P = 0.0008) with P-IFN. Fatigue (P = 0.0003), pain (P = 0.02) and appetite loss (P = 0.003) symptom scales were less in patients while on P-IFN. There were no statistically significant differences between treatment arms in QoL as measured by QLQ-MY24.

CONCLUSION

These data suggest that patients on P-IFN have a better QoL. Dose escalation studies are warranted to investigate potential impact on survival.

Complete remission of multiple myeloma after autoimmune hemolytic anemia: possible association with interferon-alpha

A patient with multiple myeloma (MM) was being maintained on human recombinant interferon-alpha (INF-alpha) after VAD and autologous bone marrow transplantation (pretreated with melphalan). An episode of immune thrombocytopenia and (Coombs positive) autoimmune hemolytic anemia (AIHA) was noted while on maintenance INF-alpha, which remitted when it was withdrawn. Following this event, he achieved a state of stable disease that persists (more than 3 years) with no specific myeloma treatment. This sequence of events suggests a relationship between an immunological reaction induced by INF-alpha and the prolonged phase of stable disease.

Pharmacotherapy of multiple myeloma

Multiple myeloma is a malignant process of the plasma cell. There is no cure for this disease and at present the focus is to manage the disease as a chronic process to achieve a good quality of life. Hopefully, with the advancement in the understanding of the pathophysiology of the disease, target therapy should allow for the control of multiple myeloma, its prevention, and/or the reversal of organ damage; therefore prolonging survival. Proteasome inhibitors and immune modulators are the first of new therapies that target the malignant plasma cell microenvironment. In this review, different aspects of these agents are discussed.

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.

Role of liposomal anthracyclines in the treatment of multiple myeloma

Patients with multiple myeloma (MM) typically respond to initial chemotherapy, but almost all patients relapse with a median survival of approximately 5 years. Combining vincristine and conventional doxorubicin with oral dexamethasone (VAD) or reduced-dose dexamethasone (VAd) provides rapid response in many patients, but its use is limited by toxicity concerns and the inconvenience of continuous infusions in each cycle. Use of pegylated liposomal doxorubicin (Doxil/Caelyx [PLD]) and vincristine intravenous injection with oral dexamethasone (DVD) or reduced-dose dexamethasone (DVd) is safe and effective for the management of newly diagnosed or relapsed/refractory MM. Controlled trials showed that DVD/DVd is at least as effective as VAD/VAd for the treatment of MM, but DVd is associated with less neutropenia and alopecia in addition to requiring fewer days in the hospital or clinic for drug administration. DVd therapy has also been reported to be associated with an antiangiogenic effect not observed with VAD. Another liposomal anthracycline, liposomal daunorubicin (DaunoXome [DNX]), has been investigated in MM and preliminary data suggest that it is safe and effective, but studies comparing it with other regimens have not been reported. Early results from ongoing trials suggest that adding thalidomide, bortezomib, or other immune modulators to PLD-based chemotherapy may improve efficacy.

Phase 2 study of arsenic trioxide in patients with relapsed or refractory multiple myeloma

Despite aggressive and innovative therapy, patients with multiple myeloma (MM) invariably relapse and die of their disease. New options for non-cytotoxic salvage therapy and additional therapeutic strategies are needed. Arsenic trioxide, an antitumour agent with a multifaceted mechanism of action, induces apoptosis in vitro in MM cell lines and freshly isolated cells from MM patients and, in preliminary studies, displayed clinical activity in patients with late-stage MM. A phase 2, multicentre, open-label study of arsenic trioxide was conducted in 24 MM patients; eight had relapsed and 16 were refractory to prior therapy. Patients received arsenic trioxide 0.25 mg/kg/d for 5 d/week during the first 2 weeks of each 4-week cycle. Sixteen patients had grade 3 or 4 neutropenia and one required antibiotics. Reductions (25% or more) in serum M-protein levels occurred in eight of 24 (33%) patients. An additional six (25%) patients had stable disease. The median time to response was 67.5 d, with a median duration of response of 130 d. Arsenic trioxide therapy lowered serum creatinine levels in two patients with high baseline values. These data indicate that arsenic trioxide is active and reasonably well tolerated as a single-agent salvage therapy, even in patients with late-stage, relapsed and refractory MM.

Interferons: mechanisms of action and clinical applications

PURPOSE OF REVIEW

Interferons are pleiotropic cytokines that exhibit important biologic activities, including antiviral, antitumor, and immunomodulatory effects. These cytokines have found important applications in clinical medicine, including the treatment of certain malignancies. The purpose of this review is to provide an update on basic and clinical research in the interferon field.

RECENT FINDINGS

Significant advances have recently occurred in the field of type I interferon signal transduction. It is well known that the interferons transduce signals via activation of multiple signaling cascades, involving Jak kinases, signal transducer and activator of transcription proteins, Map kinases, and IRS and Crk proteins. Recent evidence indicates that the p38 Map kinase pathway plays an important role in type I interferon signaling in malignant cells and that its function is required for type I interferon-dependent gene transcription and generation of the antiproliferative of type I interferons. In clinical oncology, interferon-alpha remains an active and useful agent in the treatment of several malignant disorders, and efforts are underway to improve its efficacy by using different schedules and combinations with other agents.

SUMMARY

This review summarizes the mechanisms of signal transduction of interferons and the emerging new concepts in this area. An update on the clinical applications of interferons in oncology is also provided, and potential translational applications, reflecting recent advances in the field, are discussed.

A Phase I-II trial of polyethylene glycol-conjugated L-asparaginase in patients with multiple myeloma

BACKGROUND

Multiple myeloma remains an incurable disease. New agents are needed to improve therapy for patients with this disease. Previous investigators evaluated in vitro sensitivity of myeloma cells to polyethylene glycol-conjugated L-asparaginase (PEG-L-asparaginase) using the human tumor clonogenic assay. Of the 19 myeloma samples evaluated, 63% were inhibited at 0.075 IU/mL, and 74% were inhibited at 0.75 IU/mL. PEG-L-asparaginase is a form of Escherichia coli-derived L-asparaginase that is bound covalently to polyethylene glycol. Compared with the native form, it has a longer half-life and is less likely to cause allergic reactions.

METHODS

The authors conducted a Phase I-II trial using PEG-L-asparaginase as a single agent in patients with recurrent and/or refractory multiple myeloma.

RESULTS

Twenty-two patients received a median of two doses of PEG-L-asparaginase. In the 17 patients who are evaluable for response, a complete response was observed in one patient after four doses, and stable disease was observed in eight patients. Progression of disease was the reason for termination from study in the remaining eight patients. The median survival was 31.7 months, with four patients who were alive at 72 months after the start of therapy. Grade 3-4 toxicity was noted by the PEG-L-asparaginase 2000 mg/m(2) level. Severe allergic reactions were noted only at the highest dose level.

CONCLUSIONS

Current data suggest that the maximal tolerated dose for single agent PEG-L-asparaginase in relapse/refractory multiple myeloma patients is 1000 mg/m(2) every 4 weeks. We could not identify any correlation between dose, plasma level and response. In this advanced group of patients we noted stable disease and/or response in 52% of evaluable patients. PEG-L-asparaginase has lower tolerance when used in the standard dosage as a single agent in this group of patients. We therefore recommend further studying of PEG-L-asparaginase dose of 1000 mg/m(2) on alternate weeks with steroids and/or other immune modulators.

Management of renal dysfunction in multiple myeloma

Multiple myeloma is frequently associated with renal dysfunction. In addition, it has been shown that the presence of renal failure indicates a higher tumor burden and consequently more aggressive disease. Patients who are diagnosed with renal insufficiency should be aggressively treated because reversal of renal insufficiency results in survival outcomes similar to patients who have normal renal function at diagnosis. However, the presence of renal impairment could add significantly to the morbidity of these patients and make it difficult to tolerate aggressive treatment regimens. Therefore, the treatment approach to this group of patients should include a thorough understanding of the feasibility and outcomes of the various antimyeloma treatments that are available, including newer options such as thalidomide. We recommend the following sequence of treatment in newly diagnosed patients with multiple myeloma with renal insufficiency (creatinine > 2 mg/dL): correction of hypercalcemia with full-dose bisphosphonates in patients with hypercalcemia, induction therapy that may be initiated before correction of hypercalcemia with bolus VAD (vincristine 2 mg, doxorubicin 40 mg/m(2), dexamethasone 40 mg on days 1-4, 9-12, and 17-20), and stem cell collection (cyclophosphamide 2.5-3 g/m(2)) with high-dose melphalan (140-150 mg/m(2)) with autologous stem cell transplant. Dialysis support should be considered whenever necessary for all newly diagnosed patients if renal function does not improve with aggressive initial therapy. For patients who develop renal insufficiency later in the course of the disease, therapeutic options need to be tailored to the patient's treatment history, disease status, and performance status.

In multiple myeloma, t(4;14)(p16;q32) is an adverse prognostic factor irrespective of FGFR3 expression

This study analyzed the frequency and clinical significance of t(4;14)(p16;q32) in multiple myeloma (MM) among 208 patients with MM and 52 patients with monoclonal gammopathy of undetermined significance (MGUS); diagnosed between 1994 and 2001. Patients with the translocation were identified using reverse transcription-polymerase chain reaction (RT-PCR) to detect hybrid immunoglobulin heavy chain (IgH)-MMSET transcripts from the der(4) chromosome. We found 31 (14.9%) t(4;14)(+) MM patients and 1 (1.9%) t(4;14)(+) MGUS patient. IgH-MMSET hybrid transcripts were detected in bone marrow (BM) and blood. Breakpoint analysis revealed that 67.7% of t(4;14)(+) patients expressed hybrid transcripts potentially encoding full-length MMSET, whereas the remainder lacked one or more amino terminal exons. Expression of fibroblast growth factor receptor 3 (FGFR3), presumptively dysregulated on der(14), was detected by RT-PCR in only 23 of 31 (74%) patients with t(4;14)(+) MM. Patients lacking FGFR3 expression also lacked detectable der(14) products. Longitudinal analysis of 53 MM patients with multiple BM and blood samples showed that, over time, BM from t(4;14)(+) patients remained positive and that t(4;14)(-) patients did not acquire the translocation. IgH-MMSET hybrid transcripts and FGFR3 transcripts disappeared from blood during response to therapy. No correlation was observed between the occurrence of t(4;14) and known prognostic indicators. However, we find the t(4;14) translocation predicts for poor survival (P =.006; median, 644 days vs 1288 days; hazard ratio [HR], 2.0), even in FGFR3 nonexpressors (P =.003). The presence of t(4;14) is also predictive of poor response to first-line chemotherapy (P =.05). These results indicate a significant clinical impact of the t(4;14) translocation in MM that is independent of FGFR3 expression.

Maintenance with pamidronate following first-line MP or VAD therapy in multiple myeloma

We investigated the anti-tumor effect of pamidronate after obtaining a decrease of serum monoclonal immunoglobulin (Ig) level by conventional chemotherapy in patients with multiple myeloma (MM) in order to evaluate whether the drug is useful as maintenance therapy for MM. Eight patients with MM received 60 mg/d pamidronate every third week for 6-18 months without chemotherapeutic agents or corticosteroids after the treatment with melphalan and prednisolone, or vincristine, adriamycin and prednisolone. Serum Ig and beta2-microglobulin (b2MG) levels were maintained at the levels obtained after the termination of chemotherapy in six and four out of eight patients, respectively. Hemoglobin levels were maintained at, or increased to more than, the levels observed at the end of chemotherapy in six patients. Decreased plasma cells in the bone marrow after the chemotherapy were evident in five patients. Two patients were categorized as non-responders, because Ig and b2MG increased and anemia progressed after treatment with the drug. Despite the very small numbers, the results suggest that pamidronate may have anti-tumor activity and be useful for treatment after the conventional chemotherapy in some cases of MM.

Cost-effectiveness of a transplantation strategy compared to melphalan and prednisone in younger patients with multiple myeloma

High dose chemotherapy with autologous stem cell transplantation (ASCT) improves outcomes in patients 65 years of age or less with multiple myeloma. Survival and costs in a cohort of 16 patients who received melphalan and prednisone as part of a clinical trial were compared with those of 36 patients referred to our centre for consideration of ASCT. In the transplant group, survival and costs were extrapolated to match the period of observation in the melphalan and prednisone group. Patient-specific and average costs were calculated from the perspective of the Ontario Ministry of Health. Costs and survival were varied by 50% in the sensitivity analysis. Transplantation improved life expectancy by 19.3 months with a cost difference of 30,517 Canadian dollars. The incremental cost-effectiveness of transplantation compared with melphalan and prednisone was 25,710 Canadian dollars per life-year gained when additional pamidronate and follow-up costs were considered. Discounting costs and survival at 3 and 5% did not result in important differences. The sensitivity analysis resulted in best and worse case scenarios for transplantation compared with melphalan and prednisone of 13,049 dollars and 63,954 dollars per life-year gained respectively. In comparison with melphalan and prednisone, ASCT appears to be cost-effective in patients 65 years old or younger with myeloma.

A Phase II trial of pegylated liposomal doxorubicin, vincristine, and reduced-dose dexamethasone combination therapy in newly diagnosed multiple myeloma patients

BACKGROUND

Patients with multiple myeloma (MM) have increased bone marrow angiogenesis, a low plasma cell labeling index, and multidrug resistance (the primary cause of chemotherapy failure). MM patients receiving the vincristine, doxorubicin, and dexamethasone (VAD) regimen develop resistance and cardiac and steroid toxicity. Pegylated liposomal doxorubicin (Doxil/CAELYX) could potentially extend the duration of malignant plasma cell exposure to therapeutic levels of doxorubicin. This Phase II study evaluates combination pegylated liposomal doxorubicin, vincristine, and reduced-dose dexamethasone in MM patients.

METHODS

Thirty-three newly diagnosed patients with MM received intravenous pegylated liposomal doxorubicin (40 mg/m(2)), vincristine (2.0 mg, Day 1), and oral or intravenous dexamethasone (40 mg per day for 4 days) every 4 weeks for six or more cycles and/or for two cycles after the best response.

RESULTS

The overall response rate was 88%: 4 (12%) patients achieved a complete response, 18 (55%) a major response, and 7 (21%) a minor response. Three patients (9%) had stable and one (3%) had progressive disease. The median time to progression was 23.1 months, with 2-year and 3-year progression-free survival rates of 42% and 23%, respectively. The patient survival rate at 3 years was 67%. No patients discontinued treatment due to adverse events. Myelosuppression was manageable. The most common toxicities were Grade 3 palmar-plantar erythrodysesthesia, mucositis, and neutropenia. Only one patient experienced cardiotoxicity.

CONCLUSIONS

Substituting pegylated liposomal doxorubicin for doxorubicin in the VAD regimen and reducing the dose of dexamethasone in patients with MM improve the safety profile and convenience of the treatment regimen without compromising efficacy.

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.

Protein kinase ERK contributes to differential responsiveness of human myeloma cell lines to IFNalpha

BACKGROUND: Despite IFNalpha has been used extensively in the treatment of multiple myeloma (MM), there are also several reports suggesting that IFNalpha may aggravate isease in some MM patients. That means the effect of IFNalpha on the growth of myeloma cells in vivo may be different. In this study, we selected two human myeloma cell lines that vary remarkably in response to IFNalpha and focused on elucidating the mechanism of differential IFNalpha responsiveness. RESULTS: Sko-007 is a myeloma cell line whose growth is arrested by IFNalpha; however, IFNalpha promoted the proliferation of the other myeloma cell line U266. We observed that the growth-stimulation effect of IFNalpha on U266 cells did not result from up-regulation of the IL-6 receptors on cell surface; while IFNalpha treatment on Sko-007 cells significantly reduced gp130 expression. Moreover, the transcription factors STAT3 and STAT1, which are involved in the JAK/STAT signal transduction pathway, can be activated in both IFNalpha-stimulated and -inhibited myeloma cell lines; while the activation of the protein kinase ERK, which is involved in the Ras/MAPK signal transduction pathway, can be down-regulated in IFNalpha-arrested Sko-007 cells and up-regulated in IFNalpha-stimulated U266 cells. In addition, both IFNalpha-induced growth-stimulation effect and the up-regulated activation of ERK in U266 cells were efficiently inhibited by PD98059, the specific inhibitor of MAPK/ERK kinase (MEK). CONCLUSION: Myeloma cells responsiveness to IFNalpha is heterogeneous and the activation state of ERK in the Ras/MAPK signalling pathway mainly contributed to this difference.

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)

Treatment of myeloma: recent developments

Melphalan was the first described treatment for patients with multiple myeloma in the 1960s and is still being used in clinical practice. However, the use of melphalan in combination with prednisone resulted in a median survival of only 2-3 years. Therefore, the dose of melphalan has been intensified since then (140-200 mg/m(2)). In order to diminish treatment-related morbidity and mortality due to severe myelosuppression induced by these regimens, high-dose melphalan is currently supported with autologous stem cells. Indications for high-dose therapy and the role of further intensification by performing second or allogeneic transplantations are discussed. Furthermore, new therapeutic modalities, such as inhibitors of angiogenesis, also showing direct antiproliferative, cytokine-related and immunomodulatory effects on plasma cells (thalidomide and its newer derivatives), inhibitors of the transcription factor NF-kappa B (proteasome inhibitors) and immunotherapy are described.

Relapsed multiple myeloma

The treatment of relapsed multiple myeloma remains a challenge for clinicians. Most salvage therapies result in transient responses, with median survival from relapse ranging from 6 to 18 months. No randomized trials comparing salvage therapies have been performed. In the absence of a "gold standard" salvage therapy, relapsed patients should be considered for clinical trials. In light of the recent observation that thalidomide alone brings about a 30% to 35% response rate with manageable toxicities, this is the most promising single agent available to treat relapsed disease. The maximum effective dose appears to be 400 mg/d; virtually all responses are evident within 2 months of starting therapy. Combination therapy of thalidomide with pulse dexamethasone or other chemotherapeutic agents has shown promise in pilot trials. Even with thalidomide-responsive disease, the response duration is brief, ranging from 3 to 6 months. Therefore, the authors recommend that patients under the age of 78 years who have acceptable physiologic organ function, chemotherapy-sensitive disease, third-party financial coverage, and adequate hematopoietic stem cells be considered for high-dose therapy with autologous hematopoietic stem cell transplant. High-dose therapy with hematopoietic stem cell transplant provides the highest response rate, response duration, and survival compared with historical controls treated with conventional therapy. Patients under the age of 70 years who have human leukocyte antigen-compatible donors should be considered for immune-based therapy using nonmyeloablative preparative regimens with allogeneic hematopoietic stem cell transplant.

Thalidomide in the treatment of multiple myeloma

Thalidomide--banned from clinical use in the 1960s because of severe teratogenicity--is now back in clinical practice as an effective agent in the treatment of relapsed and refractory multiple myeloma. Several clinical trials have determined that thalidomide is active in 25-35% of patients with relapsed myeloma. The role of thalidomide in early-stage myeloma is being actively investigated. Thalidomide has antiangiogenic and immunomodulatory properties and is an effective inhibitor of TNF-alpha. However, the mechanism of its action in myeloma remains unclear. Major toxicities of thalidomide include constipation, sedation, skin rash, fatigue and peripheral neuropathy. This paper summarizes the current status of thalidomide in multiple myeloma.

Interferon as therapy for multiple myeloma: an individual patient data overview of 24 randomized trials and 4012 patients

Many randomized trials have evaluated alpha-interferon as myeloma therapy, some suggesting a benefit and others not. Most were too small to give reliable answers, so a systematic overview has been performed to provide a more reliable estimate of the effect of interferon. The main end-points were response rates (induction trials), progression-free survival (PFS) and overall survival (OS). Individual patient data were supplied for 24 trials involving 4012 patients, 12 induction trials (2469 patients) and 12 maintenance trials (1543 patients). In induction, response rates were slightly better with interferon (57.5% versus 53.1%, P = 0.01). PFS was better with interferon (33% versus 24% at 3 years, P < 0.00001), an effect seen in both induction (P = 0.0003) and maintenance (P < 0.00001) trials. Median time to progression was increased by about 6 months in both settings. OS was somewhat better with interferon (53% versus 49% at 3 years, P = 0.01) with median survival increased by about 4 months. This benefit was restricted to the smaller trials. The effect of interferon was not significantly related to the dose or duration of interferon or to patients' characteristics. PFS was improved with interferon, but the survival benefit, if any, was small and needs balancing against cost and toxicity.

Management of patients with multiple myeloma: emphasizing the role of high-dose therapy

Treatment for multiple myeloma should not be given until the patient is symptomatic or at risk for the occurrence of complications of the disease. If the patient is younger than 70 years, the physician should seriously consider an autologous peripheral blood stem cell transplant. Most physicians initially administer vincristine/doxorubicin/dexamethasone (VAD) for 3 to 4 months and then collect the stem cells before exposure to alkylating agents. Following stem cell collection, one may proceed with high-dose chemotherapy and then infusion of the stem cells, or one can administer alkylating agents until a plateau is reached and delay transplantation until progressive disease occurs. There is no difference in overall survival between early and late transplantation, but the former avoids the cost and inconvenience of alkylating agent therapy. Double or tandem autologous stem cell transplants may produce better results, but the evidence is not strong. Almost all patients have a relapse after an autologous stem cell transplant, so efforts are being made to prolong the response with a2-interferon or dendritic cell therapy. Allogeneic bone marrow transplantation is feasible for only 5%-10% of patients, but the mortality is high and it is curative in only a small fraction of patients. Treatment with melphalan and prednisone results in an objective response in 50%-60% of patients. Combinations of alkylating agents produce a higher response rate, but there is no survival benefit. Thalidomide produces an objective response in about one third of patients with refractory disease. It currently is being studied in conjunction with dexamethasone for conventional initial therapy.

Interferon in multiple myeloma--summary of treatment results and clinical implications

Even though interferon (IFN) has been used in myeloma treatment for more than two decades, its efficacy is still controversial. Meta-analysis of randomized trials is based either on individual patient data or on published data. We performed meta-analyses on published and reported data using, in addition to the standard method, three independent methods of evaluating Kaplan-Meier curves. Thirty randomized trials on IFN induction or maintenance treatment were meta-analyzed. Combined IFN-chemotherapy induction treatment resulted in significant increases of repsonse rates (6.6%), as well as median relapse-free (4.8 months) and overall survival (3.1 months). IFN maintenance treatment prolonged median relapse-free survival by 4.4 months, median overall survival by 7.9 months. Drug costs of IFN per 1-year survival gain were US$ 42,236.19 for induction therapy and US$ 18,114.95 for maintenance treatment. To conclude, our results a are in accordance with those obtained from individual patient data by the Myeloma Trialists' Collaborative Group. Because of the consistent, though limited, improved trial outcomes, IFN treatment should be suggested to all myeloma patients who might benefit from it.

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.

Interferon-alpha treatment in multiple myeloma: meta-analysis of 30 randomised trials among 3948 patients

BACKGROUND

After two decades of interferon (IFN) treatment in myeloma patients and many randomised clinical trials, no definite proof of its benefits exists. This meta-analysis of all available relevant published data tests the differences between IFN and control arms in a large patient population and addresses the issue of cost-effectiveness.

PATIENTS AND METHODS

Meta-analysis was performed on 17 trials among 2333 patients who received IFN-chemotherapy induction treatment or chemotherapy alone and on 13 trials among 1615 patients on IFN maintenance therapy or without treatment. Response rates and parameters of published Kaplan Meier relapse-free and overall survival curves were analysed.

RESULTS

Patients in IFN arms showed significantly better results in all investigated parameters: IFN-chemotherapy induction treatment yielded 6.6% higher response rates (2P < 0.002) as well as 4.8-month and 3.1-month prolongations of relapse-free (P < 0.01) and overall survival (P < 0.01), respectively. Interferon maintenance therapy lead to 4.4-month (P < 0.01) and 7.0-month (P < 0.01) prolongations of relapse-free and overall survival, respectively. Meta-analysis of all IFN trials combined resulted in 4.6-month and 3.7-month IFN-related gains in relapse-free and overall survival, respectively. As early as 6 and 12 months after the start of IFN treatment, percentages of cumulative relapse-free and overall survival were always significantly higher in IFN trial arms. IFN drug expenses for a one-year survival gain, as determined from AUCs of best-fitted Gompertz functions of IFN and control survival curves, were estimated to be US$42,482.28 for induction therapy and US$18,968.16 for maintenance treatment.

CONCLUSIONS

Significantly superior outcomes were consistently found in IFN trial arms by meta-analysis of published data. These results are in accordance with a concomittantly conducted meta-analysis on individual patient data but were much easier to accrue. Taking all our results into account. i.e., the consistently significant, although limited, improvement of clinical outcomes and its acceptable cost-effectiveness, IFN treatment of patients with multiple myeloma seems worthwhile to be considered.

A review of angiogenesis and antiangiogenic therapy with thalidomide in multiple myeloma

Angiogenesis is the formation of new blood vessels and occurs physiologically during embryonal growth, wound healing and during the menstrual cycle. It is essential for the proliferation and metastases of most malignant neoplasms. Recent evidence suggests that angiogenesis is increased in multiple myeloma and has prognostic value in the disease. Angiogenic cytokines such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor are expressed by myeloma cells and appear to play a role in the increased angiogenesis seen in myeloma. In addition, VEGF may serve as a paracrine growth factor for myeloma cells. Based on the increased angiogenesis observed in myeloma, thalidomide has been studied as antiangiogenic therapy. Although its mechanism of action in myeloma is still unclear, thalidomide appears to be active in 25-30% of patients with refractory myeloma. Major toxicities include constipation, sedation, skin rash, fatigue, and peripheral neuropathy. Studies are ongoing to determine its role as initial treatment for myeloma. This paper reviews the available data on angiogenesis in myeloma, and summarizes the role of thalidomide therapy in this disease. The pharmacology and toxicity of thalidomide are also discussed.

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.

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.

Therapeutic options in the treatment of multiple myeloma: pharmacoeconomic and quality-of-life considerations

A review of current treatment options in multiple myeloma is presented, including data on health-related quality of life and pharmacoeconomics. For induction chemotherapy, no combination of cytostatic drugs has been shown to be consistently superior to the simple cyclic oral treatment with melphalan and prednisone that has been available for 30 years. The total resource consumption and direct costs per patient treated with melphalan and prednisone is approximately $US10,000 (1995 values). As median survival is prolonged from less than a year in untreated patients to 30 to 36 months, this treatment must be considered cost effective. Interferon-alpha has a modest effect on progression-free and overall survival when added to chemotherapy regimens. However, the high cost and toxicity of this drug results in an unfavourable cost-utility ratio, estimated to be between $US50,000 to $US100,000 per quality-adjusted life-year gained. Clinical trials suggest that high dose chemotherapy followed by autologous stem cell support administered to patients who have achieved disease stabilisation or objective response to conventional induction chemotherapy, prolongs median survival by about 1.5 years. Preliminary cost-utility analyses suggest a cost per life-year gained of $US30,000 to $US40,000. Further potential improvements of this therapeutic modality are under way. Several bisphosphonates have been tested for the ability to prevent the skeletal complications of multiple myeloma. Monthly infusions of pamidronate have been shown in 1 randomised trial to significantly reduce the rate of skeletal complications. Unfortunately, the rapid and widespread acceptance of this therapy seems to preclude further prospective, placebo-controlled trials with cost-utility evaluation.

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.

[Standard treatment of multiple myeloma]

INTRODUCTION

About 50% of patients with multiple myeloma are older than 65 years and are not eligible for high-dose therapy, which has proved to be more efficacious than standard-dose chemotherapy in young patients.

CURRENT KNOWLEDGE AND KEY POINTS

Apart from high-dose therapy, no clear therapeutic advance has been achieved in the past 20 years, and melphalan-prednisone combinations remain reference treatments for many patients with multiple myeloma. Despite a great number of clinical trials, the use of interferon alpha is still controversial. The role of high-dose dexamethasone has been recently established and we are currently comparing dexamethasone alone, melphalan-dexamethasone and dexamethasone-interferon alpha treatments in a multicenter randomized trial (IFM 95-01). Bisphosphonates have also emerged as an efficacious and well tolerated adjuvant treatment. Optimal use of recently released bisphosphonates at various stages of the disease will possibly lead to a clear therapeutic advantage.

FUTURE PROSPECTS AND PROJECTS

Other drugs, such as erythropoietin or interferon gamma require further evaluation. The recent implication of metalloproteinases in multiple myeloma and the efficacy of metalloproteinase inhibitors in animal models and phase I/II clinical studies in solid tumors provide a strong rationale for the clinical evaluation of these agents in multiple myeloma.

Current drug therapy for multiple myeloma

Recent years have witnessed tremendous advances in the molecular pathogenesis and management of multiple myeloma. Standard chemotherapy (melphalan and prednisone; MP) has been the mainstay of treatment of multiple myeloma for about 3 decades. However, it is no longer considered the 'gold standard', particularly for those patients who will subsequently undergo intensive chemotherapy with autologous or allogeneic peripheral blood stem cell (PBSC) or bone marrow transplantation (BMT), or for patients with refractory myeloma. A variety of induction combination chemotherapy regimens have been developed, some of which have demonstrated an improved response rate and duration and a superior 5-year survival rate when compared with standard chemotherapy. The early use of high dose chemotherapy with autologous PBSC support or BMT has significantly increased the complete remission rate, and has prolonged event-free sur vival and overall survival. Allogeneic bone marrow or PBSC transplantation may be a good option for selected patients with poor prognostic features. The role of interferon-alpha in multiple myeloma is still inconclusive despite many years of clinical evaluation. The clinical application of chemosensitising agents that can inhibit P-glycoprotein (P-gp) expression and function, and particularly the development of more potent P-gp modulators such as valspodar (PSC 833) and elacridar (GF120918) has made it possible to reverse multidrug resistance in some refractory patients and to enhance the efficacy of chemotherapeutic agents. Immunotherapeutic approaches to purging of autologous bone marrow or PBSC, or as adjuvant therapy for minimal residual disease, show great promise. Finally, a number of new therapies specifically designed to treat many of the complications of multiple myeloma are improving clinical outcomes and quality of life for these patients.

Novel biologic approaches to hematologic malignancies

Biologic agents have made a major impact on the treatment of hematologic malignancies and will continue to play a major role as we better understand their function in normal and malignant cell regulation. The examples provided in this chapter are a brief introduction to the potential of these agents. Many have yet to be used in conjunction with current cytotoxic therapy in these diseases, and perhaps combinations will prove even more successful. This possibility provides substantial ground for further investigation and therapy.