Partially T-cell-depleted allogeneic stem-cell transplantation for first-line treatment of multiple myeloma: a prospective evaluation of patients treated in the phase III study HOVON 24 MM

Allogeneic hematopoietic stem cell transplantation in patients with multiple myeloma

Aim. To analyze the effectiveness of allogeneic hematopoietic stem cell transplantation (allo-HSCT) from a related HLA-identical donor in patients with multiple myeloma (MM). Materials and methods. From 2013 to 2018, the study included 8 patients (6 men, 2 women) aged from 27 to 55 years (median 39 years) with MM who underwent allo-HSCT from a related HLA-identical donor (7 patients after auto-HSCT, in 1 case without previous auto-transplantation). All patients required 2 or more lines of induction therapy, while the achieved antitumor effect was unstable. Before allo-HSCT, complete and very good partial remission was determined in isolated cases, in 4 patients the response was regarded as partial remission, stabilization in 1 observation, progression in 1 patient. All patients underwent reduced intensity conditioning (fludarabine 30 mg/m2 6 days + busulfan 4 mg/kg 2 days). Immunosuppressive therapy included the administration of antithymocyte globulin and post-transplant cyclophosphamide. Results. Severe acute GVHD (grade 34) was observed in 3 (37.5%) cases, which resulted in death in 1 case. A stable antitumor response was achieved in 5 (62.5%) patients, complete remission lasts for 2986 months after allo-HSCT. Specific therapy for these patients is not carried out. The 7-year progression-free survival rate was 75%, the 7-year overall survival rate was 84%, with a median follow-up of 65 months. The transplant-related mortality was 12.5%. Conclusion. Allo-HSCT is considered as an alternative method of therapy for young patients with aggressive MM. Allo-HSCT in MM in some cases leads to long-term immunological control of the tumor.

Allogeneic Hematopoietic Transplantation for Multiple Myeloma in the New Drugs Era: A Platform to Cure

Allogeneic hematopoietic cell transplantation (alloHCT) represents a treatment option for multiple myeloma (MM) patients. As shown in several studies, alloHCT is highly effective, but it is hampered by a high toxicity, mainly related to the graft-versus-host disease (GVHD), a complex immunological reaction ascribable to the donor’s immune system. The morbidity and mortality associated with GVHD can weaken the benefits of this procedure. On the other side, the high therapeutic potential of alloHCT is also related to the donor’s immune system, through immunological activity known as the graft-versus-myeloma effect. Clinical research over the past two decades has sought to enhance the favorable part of this balance, along with the reduction in treatment-related toxicity. Frontline alloHCT showed promising results and a potential for a cure in the past. Currently, thanks to the improved results of first-line therapies and the availability of effective second- or third-line salvage therapies, alloHCT is reserved for selected high-risk patients and is considered a clinical option. For donor lymphocyte infusion, bortezomib or lenalidomide have been used as consolidation or maintenance therapies post-transplant—none has become standard of care. For those patients who relapse, the best treatment should be evaluated considering the patient’s clinical status and the previous lines of therapy. The use of newer drugs, such as monoclonal antibodies or other immunotherapies in the post-transplant setting, deserves further investigation. However, acceptable toxicity and a synergic effect with the newer immune system could be hopefully expected.

Response to Novel Drugs before and after Allogeneic Stem Cell Transplantation in Patients with Relapsed Multiple Myeloma

Multiple myeloma (MM) remains as an incurable disease and, although allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative approach, most patients ultimately relapse, and their treatment remains challenging. Because allo-HSCT can modify not only the biology of the disease, but also the immune system and the microenvironment, it can potentially enhance the response to rescue therapies. Information on the efficacy and safety of novel drugs in patients relapsing after allo-HSCT is lacking, however. The objectives of this study were to evaluate the efficacy and toxicity of rescue therapies in patients with MM who relapsed after allo-HSCT, as well as to compare their efficacy before and after allo-HSCT. This retrospective multicenter study included 126 consecutive patients with MM who underwent allo-HSCT between 2000 and 2013 at 8 Spanish centers. All patients engrafted. The incidence of grade II-IV acute graft-versus-host disease (GVHD) was 47%, and nonrelapse mortality within the first 100 days post-transplantation was 13%. After a median follow-up of 92 months, overall survival (OS) was 51% at 2 years and 43% at 5 years. The median progression-free survival after allo-HSCT was 7 months, whereas the median OS after relapse was 33 months. Patients relapsing in the first 6 months after transplantation had a dismal prognosis compared with those who relapsed later (median OS, 11 months versus 120 months; P < .001). The absence of chronic GVHD was associated with reduced OS after relapse (hazard ratio, 3.44; P < .001). Most patients responded to rescue therapies, including proteasome inhibitors (PIs; 62%) and immunomodulatory drugs (IMiDs; 77%), with a good toxicity profile. An in-depth evaluation, including the type and intensity of PI- and IMiD-based combinations used before and after allo-HSCT, showed that the overall response rate and duration of response after allo-HSCT were similar to those seen in the pretransplantation period. Patients with MM who relapse after allo-HSCT should be considered candidates for therapy with new drugs, which can achieve similar response rates with similar durability as seen in the pretransplantation period. This pattern does not follow the usual course of the disease outside the transplantation setting, where response rates and time to progression decreases with each consecutive line of treatment.

Utilization of hematopoietic stem cell transplantation for the treatment of multiple myeloma: a Mayo Stratification of Myeloma and Risk-Adapted Therapy (mSMART) consensus statement

Over the last two decades, the utilization of various novel therapies in the upfront or salvage settings has continued to improve survival outcomes for patients with Multiple Myeloma (MM). Thus, the conventional role for hematopoietic stem cell transplantation (HSCT) in MM either in the form of an autologous stem cell transplant (ASCT) or an allogeneic stem cell transplant (Allo-SCT) warrants re-evaluation, given the aforementioned clinical advances. Here, we present a consensus statement of our multidisciplinary group of over 30 Mayo Clinic physicians with a special interest in the care of patients with MM and provide evidence-based recommendations on the use of HSCT in MM. We specifically address topics that include the role and timing of an ASCT for MM in the era of novel agents, eligibility for an ASCT, post-ASCT consolidation, and maintenance options, and finally the utility of an upfront tandem ASCT, salvage second ASCT, and an allo-SCT in MM.

Immunotherapy in myeloma: how far have we come?

The treatment of multiple myeloma (MM) has evolved substantially over the past decades, leading to a significantly improved outcome of MM patients. The introduction of high-dose therapy, especially, and autologous stem cell transplantation, as well as the development of new drugs, such as immunomodulatory drugs (IMiDs) and proteasome inhibitors have contributed to the improvement in survival. However, eventually most MM patients relapse, which indicates that there is a need for new agents and novel treatment strategies. Importantly, the long-term survival in a subset of MM patients after allogeneic stem cell transplantation illustrates the potential of immunotherapy in MM, but allogeneic stem cell transplantation is also associated with a high rate of treatment-related mortality. Recently, a better insight into several immune-evasion mechanisms, which contribute to tumor progression, has resulted in the development of active and well-tolerated novel forms of immunotherapy. These immunotherapeutic agents can be used as monotherapy, or, even more successfully, in combination with other established anti-MM agents to further improve depth and duration of response by preventing the outgrowth of resistant clones. This review will discuss the mechanisms used by MM cells to evade the immune system, and also provide an overview of currently approved immunotherapeutic drugs, such as IMiDs (e.g. lenalidomide and pomalidomide) and monoclonal antibodies that target cell surface antigens present on the MM cell (e.g. elotuzumab and daratumumab), as well as novel immunotherapies (e.g. chimeric antigen receptor T-cells, bispecific antibodies and checkpoint inhibitors) currently in clinical development in MM.

Allograft for Myeloma: Examining Pieces of the Jigsaw Puzzle

Multiple myeloma (MM) cure remains elusive despite the availability of newer anti-myeloma agents. Patients with high-risk disease often suffer from early relapse and short survival. Allogeneic hematopoietic cell transplantation (allo-HCT) is an “immune-based” therapy that has the potential to offer long-term remission in a subgroup of patients, at the expense of high rates of transplant-related morbidity and mortality. Donor lymphocyte infusion (DLI) upon disease relapse after allo-HCT is able to generate an anti-myeloma response suggestive of a graft-versus-myeloma effect. Allo-HCT provides a robust platform for additional immune-based therapy upon relapse including DLI and, maintenance with immunomodulatory drugs and immunosuppressive therapy. There have been conflicting findings from randomized prospective trials questioning the role of allo-HCT. However, to this date, allo-HCT remains the only potential curable treatment for MM and its therapeutic role needs to be better defined especially for patients with high-risk disease. This review examines different aspects of this treatment and summarizes ongoing attempts at improving its therapeutic index.

Allogeneic Hematopoietic Cell Transplantation for Myeloma: When and in Whom Does It Work

The growing list of available therapies for patients with multiple myeloma has resulted in tremendously high response rates and prolonged survival. However, the cure remains elusive. A continued effort at developing strategies to utilize all available treatment modalities in the most effective manner is needed. Allogeneic hematopoietic cell transplantation (allo-HCT) is a robust platform, associated with high response rates, and provides a unique foundation on which immune therapies and novel agents can be employed to improve clinical outcomes. Patients with high-risk myeloma and those relapsing after novel agent-based therapies or early after an autologous HCT should be considered for allo-HCT, ideally in a clinical trial setting. Results from several ongoing studies are expected to provide important information that will help determine the place of allo-HCT in the myeloma treatment algorithm.

Stem Cell Transplantation for Multiple Myeloma

BACKGROUND

Multiple myeloma (MM) is the second most common hematologic malignancy, affecting approximately 14,000 new patients in the United State per year. The median overall survival is 5 years, and cure is a realistic goal for only a small minority of patients.

METHODS

A review of the literature was conducted that focused on treatment strategies for MM involving administration of high doses of chemotherapy followed by autologous or allogeneic hematopoietic stem cell transplant.

RESULTS

For over three decades, the standard treatment for MM has been a regimen of melphalan and prednisone (MP). Complete responses (CRs) have been rare, and 50% of patients have had disease that was resistant to treatment with MP. Attempts have been made to improve the outcome of MM by administering other combinations of standard doses of chemotherapy, but these treatments are equivalent in terms of overall survival. For patients who are candidates, high-dose therapy followed by autologous stem cell transplantation results in higher CR rates and improved long-term survival compared to treatment with standard doses of chemotherapy alone. While this strategy represents an advance in the treatment of MM, evidence-based reviews indicate that there are a number of issues to consider regarding the induction therapy, the collection of stem cells, and the timing, type, and number of high-dose therapies to use in this type of treatment strategy.

CONCLUSIONS

Advances have been made in autologous transplantation, allogeneic transplantation, anti-MM agents, and immunotherapy for MM. Combining these different strategies to achieve synergistic responses is an exciting possibility.

Allogeneic Blood or Marrow Transplantation with Post-Transplantation Cyclophosphamide as Graft-versus-Host Disease Prophylaxis in Multiple Myeloma

Allogeneic blood or marrow transplantation (alloBMT) may lead to long-term disease control in patients with multiple myeloma (MM). However, historically, the use of alloBMT in MM has been limited by its high nonrelapse mortality (NRM) rates, primarily from graft-versus-host disease (GVHD). We previously demonstrated that post-transplantation cyclophosphamide (PTCy) decreases the toxicities of both acute and chronic GVHD after alloBMT. Here, we examine the impact of PTCy in patients with MM undergoing alloBMT at Johns Hopkins Hospital. From 2003 to 2011, 39 patients with MM underwent bone marrow or peripheral blood alloBMT from HLA-matched related/unrelated or haploidentical related donors after either myeloablative or nonmyeloablative conditioning. Post-transplantation GVHD prophylaxis consisted of cyclophosphamide (50 mg/kg) on days +3 and +4 with or without mycophenolate mofetil and tacrolimus. Engraftment was detected in 95% of patients, with neutrophil and platelet recovery at a median of 15 and 16 days, respectively. The cumulative incidences of acute grades 2 to 4 and grades 3 and 4 GVHD were .41 and .08, respectively, and no cases of grade 4 acute GVHD were observed. The cumulative incidence of chronic GVHD was .13. One patient succumbed to NRM. All cases of chronic GVHD involved extensive disease and 60% of these patients received systemic therapy with complete resolution. After alloBMT, the overall response rate was 62% with complete, very good partial, and partial response rates of 26%, 21%, and 15%, respectively. The median progression-free survival was 12 months and was associated with the depth of response but not cytogenetic risk. The estimated cumulative incidence of relapse was .46 (95% confidence interval [CI], .3 to .62) at 1 year and .56 (95% CI, .41 to .72) at 2 years. At last follow-up, 23% of patients remain without evidence of disease at a median follow-up of 10.3 years after alloBMT. The median overall survival was 4.4 years and the 5-year and 10-year overall survival probabilities were 49% (95% CI, 35% to 67%) and 43% (95% CI, 29% to 62%), respectively. The use of PTCy after alloBMT for MM is feasible and results in low NRM and GVHD rates. The safety of this approach may allow the development of novel post-transplantation maintenance strategies to improve long-term disease control.

Hematopoietic Stem Cell Transplantation in Multiple Myeloma: A Retrospective Study of the Société Française de Greffe de Moelle et de Thérapie Cellulaire (SFGM-TC)

Because the indication of allograft (allogeneic stem cell transplantation [alloSCT]) for multiple myeloma (MM) has widened in recent years, thanks to the development of reduced-intensity conditionings (RIC), it is still unclear if myeloablative conditioning (MAC) remains appropriate. This study compares retrospectively outcomes of patients undergoing either RIC or MAC regimens for MM. Based on the SFGM-TC registry, we included 446 MM patients receiving alloSCT between 1999 and 2009 for whom a minimal data set was available. Median follow-up for the entire cohort was 33.6 months (range, 0 to 164.5). RIC and MAC populations were different regarding age (53.5 versus 47.1 years, respectively), number of prior autologous (auto)SCTs (93.2% versus 79.6% had at least 2 autoSCTs), and stem cell source (90.2% versus 61.2% received peripheral blood). For RIC and MAC populations the nonrelapse mortality at 2 years was 24.6% and 22.4%, respectively, progression-free survival 35.5% and 51.1%, and overall survival 59.5% and 66.7% (not significant). These outcomes were not affected by conditioning intensity either on univariate or multivariate analysis. Despite some limitations in the study design, these results indicate that MAC should remain a valuable option in alloSCT for MM, especially for young and less-treated patient with no comorbidity. The constant progress in induction treatments of MM and supportive care after alloSCT could improve these results in the near future.

Allogeneic hematopoietic SCT in multiple myeloma: long-term results from a single institution

The role of allogeneic hematopoietic SCT (allo-HCT) in multiple myeloma (MM) remains controversial. A total of 58 patients received an allo-HCT (25 of them with myeloablative conditioning-allo-MAC-and 33 with reduced-intensity conditioning-allo-RIC) at our institution over a 28-year period. The CR rate for allo-MAC was 36%. The incidence of grade III-IV acute GVHD (aGVHD) and chronic GVHD (cGVHD) was 28% and 39%, respectively The TRM at any time was 60% and the main causes of death were aGVHD or infectious complications not directly related to GVHD. The estimated PFS and OS at 15 years were 8% and 15%, respectively. The CR rate with allo-RIC was 45%. The incidence of grade III-IV aGVHD and cGVHD were 24% and 41%, respectively. The TRM at any time was 33% and was mainly related to aGVHD. The estimated PFS and OS at 5 years were 22% and 38%, respectively. Despite its high TRM, a proportion of patients with high-risk myeloma (early relapse and newly diagnosed ultrahigh risk) may obtain long-term disease control with allo-HCT. New approaches aimed at decreasing the incidence of aGVHD, and consequently to decrease the TRM, are needed.

Role of allogeneic stem cell transplantation in multiple myeloma

Multiple myeloma is currently incurable using standard treatment regimens. While the introduction of high-dose chemotherapy with autologous stem cell rescue has been shown to increase overall survival when compared with chemotherapy alone, this strategy is palliative. Allogeneic stem cell transplantation provides the potential for long-term disease-free survival in a small proportion of patients, although its application has been limited by procedure-related mortality, reflecting the intensive myeloablative conditioning given. Recently, reduced intensity conditioning regimens have been developed in an attempt to reduce toxicity whilst preserving the allogeneic graft-versus-myeloma effect, therefore maintaining the potential for disease eradication. This review aims to examine the current position of allogeneic transplantation in the management of myeloma.

Death of frontline allo-SCT in myeloma

In this issue of Blood, Lokhorst et al report the results of a donor versus no-donor comparison trial, which unambiguously establishes that reduced intensity conditioning allogeneic stem cell transplantation (RIC allo-SCT) should not be offered as part of frontline therapy in multiple myeloma (MM).1

An assessment of the external validity of mapping QLQ-C30 to EQ-5D preferences

BACKGROUND

Although cancer-specific Health-related Quality-of-Life measures are commonly included in randomized clinical trials or other prospective non-randomized clinical studies, it is rare that preference-based instruments are used, which allow the calculation of a Utility weight suitable for estimating Quality-adjusted Life-Years gained.

OBJECTIVE

To test the external validity of a previously published mapping algorithm to transform the EORTC QLQ-C30 questionnaire responses into EQ-5D-derived utilities by predicting EQ-5D utilities from QLQ-C30 scores.

STUDY DESIGN AND METHODS

Comparative retrospective data analysis of four multicentre, prospective clinical trials in Breast, Multiple Myeloma, Non-Hodgkin Lymphoma and Non-Small-Cell Lung cancer patients with, respectively, 219, 172, 132 and 172 patients. Regression analysis of individual pairs of EQ-5D and QLQ-C30 scores.

RESULTS

Although the internal predictive power of a previously published mapping equation was high, its external validity when tested on a set of unrelated external data sets in other cancers proved to underestimate both the mean and variance of the mapped EQ-5D utilities. Furthermore, it appears that the relationship between QLQ-C30 scores and EQ-5D values is not stable across the different data sets.

CONCLUSIONS

Validation of the proposed algorithm in other external clinical data sets should be encouraged as well as the application of other more complex mapping methods to enhance accuracy of mapping. In the meanwhile, direct mapping from QLQ-C30 profiles to EQ-5D utilities using published algorithms should be performed with reservations.

Predictors of prolonged survival after allogeneic hematopoietic stem cell transplantation for multiple myeloma

A total of 149 patients with multiple myeloma (MM) who received allogeneic hematopoietic stem cell transplantation (allo-HCT) with myeloablative (MAC; n = 38) or reduced-intensity conditioning (RIC; n = 110) regimens at MD Anderson Cancer Center were evaluated. Of the total, 120 (81%) patients had relapsed or had refractory disease. Median age of MM patients was 50 (28-70) years with a followup time of 28.5 (3-164) months. The 100-day and 5-year treatment related mortality (TRM) rates were 17% and 47%, respectively. TRM was significantly lower with RIC regimens (13%) vs. 29% for MAC at 100 days (P = 0.012). The cumulative incidence of Grade II-IV acute graft-versus-host disease (GVHD) was 35% and chronic GVHD was 46%. PFS and OS at 5 years were 15% and 21%, respectively. In multivariate analysis, allo-HCT for primary remission consolidation was associated with longer PFS (HR 0.35; 95% CI, 0.18-0.67) and OS (HR 0.29; 95% CI 0.15-0.55), while absence of high-risk cytogenetics was associated with longer PFS only (HR 0.59; 95% CI 0.37-0.95). We observe that TRM has decreased with the use of RIC regimens, and long-term disease control can be expected in a subset of MM patients undergoing allo-HCT. Further studies should be conducted in carefully designed clinical trials in this patient population.

Evolving role of high dose stem cell therapy in multiple myeloma

Conventional chemotherapy has been used in the treatment of multiple myeloma. However the development of autologous stem cell transplant represented a major advance in its therapy. Complete response (CR) rates to the tune of 40-45% were seen and this translated into improvements in progression-free survival and also overall survival in some studies. As a result the autologous stem cell transplants (ASCT) is the standard of care in eligible patients and can be carried out with low treatment-related mortality. Allogenic transplant carries the potential for cure but the high mortality associated with the myeloablative transplant has made it unpopular. Reduced Intensity Stem Cell Transplants (RIST) have been tried with varying success but with a high degree of morbidity as compared to the ASCT. Introduction of newer agents like thalidomide, lenalidomide, bortezomib and liposomal doxorubicin into the induction regimens has resulted in higher CR and very good partial response rates (VGPR) as well as improvement in ease of administration. These drugs have also proved useful in patients with adverse cytogenetics. Recent trials suggest that this has translated into improvements in response rates post-ASCT. There is a suggestion that patients achieving CR/nCR or VGPR after induction therapy should be placed on maintenance and ASCT then could be used as a treatment strategy at relapse. All these trends however await confirmation from further trials. Tandem transplants have been used to augment the results obtained with ASCT and have demonstrated their utility in patients who achieved only a partial response or stable disease in response to the first transplant as well as patients with adverse cytogenetics. Incorporation of bortezomib along with melphalan into the conditioning regimen has also been tried. RIST following ASCT has been tried with varying success but does not offer any major advantage over ASCT and is associated with higher morbidity. It is hoped that recent advances in therapy will contribute greatly to improved survival.

International Myeloma Working Group Consensus Statement Regarding the Current Status of Allogeneic Stem-Cell Transplantation for Multiple Myeloma

Purpose

To define consensus statement regarding allogeneic stem-cell transplantation (Allo-SCT) as a treatment option for multiple myeloma (MM) on behalf of International Myeloma Working Group.

Patients and Methods

In this review, results from prospective and retrospective studies of Allo-SCT in MM are summarized.

Results

Although the introduction of reduced-intensity conditioning (RIC) has lowered the high treatment-related mortality associated with myeloablative conditioning, convincing evidence is lacking that Allo-RIC improves the survival compared with autologous stem-cell transplantation.

Conclusion

New strategies are necessary to make Allo-SCT safer and more effective for patients with MM. Until this is achieved, Allo-RIC in myeloma should only be recommended in the context of clinical trials.

Hematopoietic stem cell transplantation for multiple myeloma beyond 2010

Autologous stem cell transplantation (ASCT) is considered the gold standard in the frontline therapy of younger patients with multiple myeloma because it results in higher complete remission (CR) rates and longer event-free survival than conventional chemotherapy. The greatest benefit from ASCT is obtained in patients achieving CR after transplantation, the likelihood of CR being associated with the M-protein size at the time of transplantation. The incorporation of novel agents results in higher pre- and posttransplantation CR rates. Induction with bortezomib-containing regimens is encouraging in patients with poor-risk cytogenetics. However, longer follow-up is required to assess the impact of this increased CR on long-term survival. The results of posttransplantation consolidation/maintenance with new drugs are encouraging. All this indicates that, in the era of novel agents, high-dose therapy should be optimized rather than replaced. Because of its high transplantation-related mortality, myeloablative allografting has been generally replaced by reduced-intensity conditioning (reduced intensity conditioning allogeneic transplantation). The best results are achieved after a debulky ASCT, with a progression-free survival plateau of 25% to 30% beyond 6 years from reduced intensity conditioning allogeneic transplantation. The development of novel reduced-intensity preparative regimens and peri- and posttransplantation strategies aimed at minimizing graft-versus-host disease, and enhancing the graft-versus-myeloma effect are key issues.

Autologous-allogeneic tandem stem cell transplantation in patients with multiple myeloma

The decrease in treatment-related mortality by using reduced intensity conditioning and the well-proven immunological effect of the graft to multiple myeloma cells has increased the interest in using allogeneic stem cell transplantation in patients with multiple myeloma. The concept of a cytoreductive autograft followed by a dose-reduced allogeneic stem cell transplantation appears to be the most promising approach. Preliminary reports of several groups observed a treatment-related mortality at 1 year ranged from 0-17%. The rate of acute graft-vs.-host disease (GvHD) grade II-IV ranged from 32-44% and of chronic GvHD from 28-64%. The overall response rates for all studies ranged from 68-83%, including a high rate of complete remissions of 52-83%. The overall survival at 2 or 3 years was between 62% and 78%, and the progression-free survival between 54% and 56%. Despite the high rate of complete remissions after autologous-allogeneic tandem transplantation observed in nearly all trials, the relapse rate is quite considerable and exceeded nearly 40% at 2 years. Therefore, the reduced allogeneic treatment approach in patients with multiple myeloma has still to be improved and further preclinical and clinical research is focused on two major issues: (i) to further reduce treatment-related mortality and (ii) to enhance the remission status after transplantation, via adoptive immunotherapy inducing molecular remission and enhancing the cure rate of this approach.

Role of allogeneic stem cell transplantation in multiple myeloma

High-dose chemotherapy with autologous stem cell rescue has been regarded as the standard of care for young newly diagnosed myeloma patients. Moreover, the development of new agents with potent anti-tumor activity has further improved survival. However, relapse is a continuous risk primarily due to the inability of current therapies to eradicate all myeloma cells. Allografting is the only potentially curative treatment at least for a subset of multiple myeloma patients due to its well documented graft-versus-myeloma effects. Given the high transplant mortality of the high-dose myeloablative conditionings used until recently, allografting has for a long time been limited to younger relapsed/refractory patients. These limitations have been reduced significantly by the use of reduced-intensity conditionings. Although results of recent trials are encouraging, the subset of patients who may benefit most from an allograft remains to be determined. An overview of the clinical outcomes obtained with allografting and possible future developments are reported.

Emerging therapies for multiple myeloma

Multiple myeloma (MM) is a clonal plasma cell malignancy clinically characterized by osteolytic lesions, immunodeficiency, and renal disease. There are an estimated 750,000 people diagnosed with MM worldwide, with a median overall survival of 3 - 5 years. Besides chromosomal aberrations, translocations, and mutations in essential growth and tumor-suppressor genes, accumulating data strongly highlight the pathophysiologic role of the bone marrow (BM) microenvironment in MM pathogenesis. Based on this knowledge, several novel agents have been identified, and treatment options in MM have fundamentally changed during the last decade. Thalidomide, bortezomib, and lenalidomide have been incorporated into conventional cytotoxic and transplantation regimens, first in relapsed and refractory and now also in newly diagnosed MM. Despite these significant advances, there remains an urgent need for more efficacious and tolerable drugs. Indeed, a plethora of preclinical agents awaits translation from the bench to the bedside. This article reviews the scientific rationale of new therapy regimens and newly identified therapeutic agents - small molecules as well as therapeutic antibodies - that hold promise to further improve outcome in MM.

Role of stem cell transplantation

Hematopoietic stem cell transplantation (SCT) was introduced in the treatment of multiple myeloma in the 1980s. In the autologous setting, the use of peripheral blood stem cells instead of bone marrow has markedly improved feasibility. In fit patients who have normal renal function and are younger than 65 years of age, randomized studies have shown the superiority of autologous stem cell transplantation (ASCT) compared with conventional chemotherapy. ASCT is now considered the standard of care in this population of patients. It is currently challenged, however, by the introduction of novel agents, such as thalidomide, bortezomib, and lenalidomide. The role of allogenic SCT remains controversial, even with reduced intensity conditionings. Prospective studies still are needed to evaluate the impact of both autologous and allogeneic SCT in this new era.

The allogeneic dilemma

The place of allogeneic SCT in the management of multiple myeloma remains controversial. Although it may induce long-term clinical and molecular remissions, the very high transplant-related toxicity after a myeloablative preparative regimen has limited its role to younger patients as first-line treatment option. Even with this limited indication, toxic death rate related to infections and GVHD is considered too high and this strategy has been almost abandoned. Reduced intensity conditioning (RIC) regimens look promising, as the transplant-related mortality is low even with matched unrelated donors and can be considered for older patients up to the age of 65 years. However when used in patients with a high tumor burden or with chemo-resistant disease, the immunologic effect of the graft is not sufficient to avoid relapses. Therefore, RIC allotransplantation is currently used after tumor mass reduction with high-dose therapy followed by autologous SCT. A recently published Italian study shows that this strategy induces better event-free survival than double autologous SCT due to a reduced relapse rate. The questions raised by this encouraging result are discussed in this paper.

Mini-Midi-Maxi? How to harness the graft-versus-myeloma effect and target molecular remission after allogeneic stem cell transplantation

Allogeneic stem cell transplantation in multiple myeloma after standard myeloablative conditioning induces a high rate of complete remissions, but long-term freedom from disease is achieved in 30-40% of the cases only. The therapeutic effect of allogeneic stem cell transplantation is due to cytotoxicity of high-dose chemotherapy and immune-mediated graft-versus-myeloma effect by donor T cells. Retrospective studies clearly suggest that both (a) reducing the intensity of high-dose chemotherapy by using reduced-intensity or non-myeloablative conditioning regimen or (b) reducing the immunotherapy of donor T cells by using T-cell depletion result in lower treatment-related morbidity and mortality, but also in higher rate of relapse. Therefore, this review will focus on potential strategies of how treatment-related morbidity and mortality might be kept low without an increased risk of relapse and how remission status after transplantation can be enhanced by using the newly established donor immunosystems after allografting as a platform for post-transplant treatment strategies with new drugs (thalidomide, lenalidomide, bortezomib) or immunotherapy (donor lymphocyte infusion, vaccination, tumor-specific T cells) in order to achieve remission on a molecular level, which seems to be a 'conditio sine qua non' to cure myeloma patients.

Multiple myeloma patients receiving pre-emptive donor lymphocyte infusion after partial T-cell-depleted allogeneic stem cell transplantation show a long progression-free survival

The purpose of this study was to determine the role of pre-emptive donor lymphocyte infusion (pDLI) after partial T-cell-depleted allogeneic SCT in patients with multiple myeloma (MM). A cohort of 24 MM patients was treated with partial T-cell-depleted myeloablative SCT between December 1997 and April 2002. These patients were intended to receive pDLI after SCT. The overall response rate after SCT was 83% (20 of 24 patients) with 10 patients (42%) in complete remission (CR). Transplant-related mortality within 1 year after SCT was 29%. Thirteen patients (54%) received pDLI and four patients in partial remission reached CR. GVHD>grade I after pDLI developed in 4 out of 13 patients (30%). Four patients received therapeutic DLI, without preceding pDLI. Eleven patients (46%) are alive, with a median follow-up of 67 months (range, 48-100 months). Seven of these patients (29%) are in continuous CR (CCR), which was confirmed by a negative patient-specific IgH PCR in four patients. All seven patients in CCR received pDLI. Although myeloablative SCT in MM induces high toxicity, we show that the concept of T-cell depletion followed by pDLI is promising and needs to be investigated in a reduced-intensity conditioning setting.

Patterns of survival in multiple myeloma: a population-based study of patients diagnosed in Sweden from 1973 to 2003

PURPOSE

To define patterns of survival among all multiple myeloma (MM) patients diagnosed in Sweden during a 30-year period.

PATIENTS AND METHODS

A total of 14,381 MM patients (7,643 males; 6,738 females) were diagnosed in Sweden from 1973 to 2003 (median age, 69.9 years; range 19 to 101 years). Patients were categorized into six age categories and four calendar periods (1973 to 1979, 1980 to 1986, 1987 to 1993, and 1994 to 2003). We computed relative survival ratios (RSRs) as measures of patient survival.

RESULTS

One-year survival improved (P < .001) over time in all age groups and RSRs were 0.73, 0.78, 0.80, and 0.82 for the four calendar periods; however, improvement in 5-year (P < .001) and 10-year (P < .001) RSR was restricted to patients younger than 70 years and younger than 60 years, respectively. For the first time, in analyses restricted to MM patients diagnosed at age younger than 60 years, we found a 29% (P < .001) reduced 10-year mortality in the last calendar period (1994 to 2003) compared with the preceding calendar period (1987 to 1993). Females with MM had a 3% (P = .024) lower excess mortality than males.

CONCLUSION

One-year MM survival has increased for all age groups during the last decades; 5-year and 10-year MM survival has increased in younger patients (younger than 60 to 70 years). High-dose melphalan with subsequent autologous stem-cell transplantation, thalidomide, and a continuous improvement in supportive care measures are probably the most important factors contributing to this finding. New effective agents with a more favorable toxicity profile are needed to improve survival further, particularly in the elderly.

Stem cell transplantation in multiple myeloma

Multiple myeloma (MM) is one of the key hematologic malignancies in which the impact of dose intensity has been demonstrated. Consequently, in 2005, MM was the most common disease for which autologous stem cell transplantation (ASCT) was indicated both in Europe and in the U.S. However, ASCT is not curative, and most patients relapse within a median of 3 years. Novel agents such as thalidomide (Thalidomid), bortezomib (Velcade), or lenalidomide (Revlimid) have been introduced to improve high-dose therapy, and promising results have been reported. Conversely, results from myeloablative allogeneic stem cell transplantation remain disappointing due to high transplantation-related mortality, justifying the exploration of strategies such as reduced-intensity conditioning, which have been shown to be feasible but for which proof of efficacy requires continued study.

Prognostic factors for donor lymphocyte infusions following non-myeloablative allogeneic stem cell transplantation in multiple myeloma

In this retrospective study, we evaluated donor lymphocyte infusions given for relapsed (n=48) or persistent (n=15) myeloma following non-myeloablative allogeneic stem cell transplantation (Allo-SCT). Twenty-four of 63 patients (38.1%) responded: 12 patients (19.0%) with a partial response (PR) and 12 patients (19.0%) with a complete response (CR). Overall survival after donor lymphocyte infusions (DLI) was 23.6 months (1.0-50.7+). Median overall survival for non-responding patients was 23.6 months and has not been reached for the patients responding to DLI. In responders, progression-free survival after DLI was 27.8 months (1.2-46.2+). Patients with a PR had a median progression-free survival of 7.0 months, whereas patients with a CR to DLI had a median progression-free survival of 27.8 months. Major toxicities were acute graft-versus-host disease (GVHD) (38.1%) and chronic GVHD (42.9%). Seven patients (11.1%) died from treatment-related mortality. The only significant prognostic factors for response to DLI were the occurrence of acute and chronic GVHD. There was a trend towards significance for time between transplantation and DLI, and response. Donor lymphocyte infusion following non-myeloablative Allo-SCT is a valuable strategy for relapsed or persistent disease.

Allogeneic haematopoietic cell transplantation for multiple myeloma: reducing transplant-related mortality while harnessing the graft-versus-myeloma effect

Allogeneic haematopoietic cell transplantation (allo-HCT) provides effective therapy for patients with various haematological malignancies. In multiple myeloma (MM) this approach can induce response rates in 35-75% of patients. However, the outcome is hampered by high rates of treatment-related mortality (TRM). Reduced intensity conditioning to lower TRM has been successfully applied. The fact that previous clinical reports have documented graft-versus-myeloma (GVM) activity without graft-versus-host disease (GVHD) suggests that at least two distinct immunocompetent cell populations mediating GVHD and/or GVM may exist. Further characterization of effectors after allo-HCT and their targets may help to clarify the immune response that mediates the GVM effect. This review considers the clinical results with myeloablative and reduced intensity conditioning prior to allo-HCT for MM, with emphasis on attempts to prevent GVHD while preserving the GVM effect. Strategies including donor lymphocyte infusions as part of the allogeneic protocol and antigenic targets for GVM effect are reviewed.

Myeloablative allogeneic stem cell transplantation for advanced stage multiple myeloma: very long-term follow up of a single center experience

We aimed to review the long-term outcome of myeloablative allogeneic stem cell transplantation (SCT) performed for multiple myeloma (MM) at our institution. Records of all patients who received standard myeloablative allogeneic SCT for MM were retrospectively reviewed. Overall survival (OS), progression-free survival (PFS), and event-free survival (EFS) were calculated using the Kaplan-Meier method. In total 37 transplants had been performed. Median follow up post-SCT was 108 months (range: 33-148). The majority of patients suffered advanced stage disease and/or had received multiple prior therapies prior to SCT. Transplant-related mortality (TRM) at 100 days was 32%. Grades 2-4 acute graft-vs.-host disease (GVHD) occurred in 18 patients (49%), and extensive stage chronic GVHD in seven (28%) of 25 patients surviving greater than day 100. Median OS, PFS, and EFS were 28 months, 66 months and 13 months, respectively, with 5 year OS, PFS, and EFS 40%, 54% and 24%. Our results suggest that allogeneic SCT, even when performed in advanced stage, heavily pretreated MM, still results in long-term EFS in a significant minority of patients. Efforts should continue on alternative allogeneic SCT approaches to reduce the high early TRM rate associated with myeloablative conditioning.

Prospective comparison of autologous stem cell transplantation followed by dose-reduced allograft (IFM99-03 trial) with tandem autologous stem cell transplantation (IFM99-04 trial) in high-risk de novo multiple myeloma

The Intergroupe Francophone du Myélome (IFM) initiated 2 trials in 1999 to study patients with high-risk (β2-microglobulin level greater than 3 mg/L and chromosome 13 deletion at diagnosis) de novo multiple myeloma. In both protocols, the induction regimen consisted of vincristine, doxorubicin, and dexamethasone (VAD) followed by first autologous stem cell transplantation (ASCT) prepared by melphalan 200 mg/m2. Patients with an HLA-identical sibling donor were subsequently treated with dose-reduced allogeneic stem cell transplantation (IFM99-03 trial), and patients without an HLA-identical sibling donor were randomly assigned to undergo second ASCT prepared by melphalan 220 mg/m2 and 160 mg dexamethasone with or without anti–IL-6 monoclonal antibody (IFM99-04 protocol). Two hundred eighty-four patients—65 in the IFM99-03 trial and 219 in the IFM99-04 trial—were prospectively treated and received at least one course of VAD. On an intent-to-treat basis, overall survival (OS) and event-free survival (EFS) did not differ significantly in the studies (medians 35 and 25 months in the IFM99-03 trial vs 41 and 30 months in the IFM99-04 trial, respectively). With a median follow-up time of 24 months, the EFS of the 166 patients randomly assigned in the tandem ASCT protocol was similar to the EFS of the 46 patients who underwent the entire IFM99-03 program (median, 35 vs 31.7 months), with a trend for a better OS in patients treated with tandem ASCT (median, 47.2 vs 35 months; P = .07). In patients with high-risk de novo MM, the combination of ASCT followed by dose-reduced allogeneic transplantation was not superior to tandem dose–intensified, melphalan-based ASCT.

Stem-cell transplantation in multiple myeloma

In patient with newly diagnosed multiple myeloma (MM), randomized studies have shown that autologous stem-cell transplantation (ASCT) is superior to conventional chemotherapy, and ASCT is now standard care, at least for younger patients. The best conditioning regimen is melphalan 200 mg/m2, and the best stem-cell source is unselected peripheral progenitor cells. Recent results of the IFM94 trial show that double ASCT is superior to single ASCT, at least in patients who do not achieve a 90% response after one transplant. By combining biologic markers (beta2-microglobulin, albumin) and genetic markers (hypodiploidy, chromosome 13 deletion) it is possible to accurately predict prognosis after ASCT. The results of allogeneic SCT remain disappointing due to a high transplant mortality. Strategies combining ASCT and reduced-intensity allogeneic SCT are currently being studied.

Evolving Role of Stem Cell Transplantation in Multiple Myeloma

Autologous stem cell transplantation (ASCT) is currently considered the standard of care for younger patients with newly diagnosed multiple myeloma based on 3 randomized trials that have shown it is superior to conventional chemotherapy. However, the introduction of novel agents like thalidomide, bortezomib, or lenalidomide may improve the results of standard-dose therapy. For instance, in combination, melphalan/prednisone/thalidomide yields complete response rates comparable with those achieved with ASCT. Different strategies have been proposed to improve the results of ASCT. A randomized trial has shown that tandem ASCT is superior to single ASCT in terms of event-free survival (EFS) and overall survival. Four other randomized trials have produced results in favor of tandem ASCT. However, the benefit remains marginal and patients with poor initial characteristics still have poor outcomes. Further intensification has been tested with encouraging results in patients with high b2-microglobulin levels and chromosome 13 deletion. "Total Therapy II" with intensified induction and post-ASCT chemotherapy also appears to improve outcomes. Another possibility is the use of novel agents in combination with ASCT as part of induction therapy or as maintenance therapy after ASCT. Preliminary results of a French Intergroup study show a significant prolongation of EFS in patients receiving maintenance therapy with thalidomide. Results achieved with allogeneic stem cell transplantation remain disappointing. Although initial results of ASCT followed by reduced-intensity allogeneic stem cell transplantation were promising, with more follow-up, relapses and chronic graft-versus-host disease have limited the enthusiasm. Allogeneic stem cell transplantation should be proposed only in the context of a clinical trial.

Malignant transformation in polyneuropathy associated with monoclonal gammopathy

Objective: To assess the frequency of hematologic malignancies at diagnosis and to determine the incidence and predictors of malignant transformation during follow-up in patients with polyneuropathy associated with monoclonal gammopathy.

Methods: Potential predictors of malignant transformation from medical history, hematologic, neurologic, and laboratory examination performed each 6 months were evaluated by univariable and multivariable Cox proportional hazard analysis.

Results: Of 193 patients with polyneuropathy associated with monoclonal gammopathy, 17 patients had a hematologic malignancy at diagnosis. The incidence rate of malignant transformation in 176 patients without a malignancy at diagnosis was 2.7/100 patient years. Weight loss, progression of the polyneuropathy, unexplained fever or night sweats, and M-protein level were independent predictors.

Conclusions: Since hematologic malignancies occur frequently in polyneuropathy associated with monoclonal gammopathy, the authors suggest that all patients should be screened at diagnosis and subsequently during follow-up if malignant transformation is suspected.

Stem cell transplantation in multiple myeloma (0, 1, or 2)

PURPOSE OF REVIEW

Autologous stem cell transplantation is now considered the standard of care in patients with multiple myeloma up to 65 years of age. Therefore, two questions have been recently addressed by cooperative groups: should autologous stem cell transplantation be offered to older patients, and is it possible to improve the results of autologous stem cell transplantation, especially with double autologous stem cell transplantation? The results of allogeneic transplantation remain disappointing, with a high transplant-related mortality rate, increasing the need to explore new strategies such as reduced-intensity conditioning.

RECENT FINDINGS

A randomized Italian study confirms that two courses of intermediate-dose melphalan supported by autologous stem cell transplantation is superior to standard melphalan-prednisone even in patients aged 65 to 70. The Intergroupe Francophone du Myelome 94 (IFM94) trial shows that double transplantation is superior to single transplantation, at least in patients with less than 90% reduction of their M-component after one transplant. Several studies have addressed the issue of prognostic factors in the context of autologous stem cell transplantation. A prospective Dutch trial confirms poor results with T cell-depleted allogeneic transplantation prepared by a standard myeloablative regimen. The Seattle group, on the other hand, reports encouraging preliminary data with tandem auto/mini-allotransplantation.

SUMMARY

The available results of randomized studies are in favor of tandem autologous transplantation. In the near future, ongoing studies will clarify the role of novel agents (thalidomide and its analogs, bortezomib) in the context of autologous stem cell transplantation and the place of tandem auto/mini-allotransplantation compared with tandem autologous transplantation.

A class II-restricted cytotoxic T-cell clone recognizes a human minor histocompatibility antigen with a restricted tissue distribution

Following a human leucocyte antigen (HLA)-identical allogeneic stem cell transplantation (allo-SCT), minor histocompatibility antigens (mHags) play an important role in the induction of graft-versus-leukaemia (GvL) and graft-versus-myeloma (GvM). Many mHags show ubiquitous tissue expression and are associated with GvL and graft-versus-host disease. Here we describe a cytotoxic CD4(+) T lymphocyte line and a cytotoxic, CD4(+) T cell clone (CTC), 3AB11, which recognized a tissue-restricted mHag. This CTC was isolated from a multiple myeloma patient with clinical GvM following an HLA-matched allo-SCT. CTC 3AB11 was activated in a HLA-DP*0401 restricted fashion and the antigen was expressed by 27% of HLA-DP*0401 positive Epstein-Barr virus (EBV)-transformed B-cell lines (EBV-B). Tissue distribution analysis of antigen 3AB11 showed it to be expressed by patient-derived EBV-transformed B cell lines (EBVp), the myeloma plasma cell-line UM9 and monocytes. It was weakly expressed by peripheral blood-derived phytohaemagglutinin-induced T-cell blasts and absent on CD40L stimulated peripheral B (CD40L B) cells and stromal cells. The relatively high prevalence of the HLA class II-restricted 3AB11 antigen, together with its apparent haematopoietic-restricted expression, makes it an antigen of interest for cellular immunotherapy.