Unrelated stem cell transplantation in multiple myeloma after a reduced-intensity conditioning with pretransplantation antithymocyte globulin is highly effective with low transplantation-related mortality

Quadruple gene-engineered natural killer cells enable multi-antigen targeting for durable antitumor activity against multiple myeloma

Allogeneic natural killer (NK) cell adoptive transfer is a promising treatment for several cancers but is less effective for the treatment of multiple myeloma. In this study, we report on quadruple gene-engineered induced pluripotent stem cell (iPSC)-derived NK cells designed for mass production from a renewable source and for dual targeting against multiple myeloma through the introduction of an NK cell-optimized chimeric antigen receptor (CAR) specific for B cell maturation antigen (BCMA) and a high affinity, non-cleavable CD16 to augment antibody-dependent cellular cytotoxicity when combined with therapeutic anti-CD38 antibodies. Additionally, these cells express a membrane-bound interleukin-15 fusion molecule to enhance function and persistence along with knock out of CD38 to prevent antibody-mediated fratricide and enhance NK cell metabolic fitness. In various preclinical models, including xenogeneic adoptive transfer models, quadruple gene-engineered NK cells consistently demonstrate durable antitumor activity independent of exogenous cytokine support. Results presented here support clinical translation of this off-the-shelf strategy for effective treatment of multiple myeloma.

ASTCT Clinical Practice Recommendations for Transplantation and Cellular Therapies in Multiple Myeloma

Over the past decade, therapeutic options in multiple myeloma (MM) have changed dramatically. Given the unprecedented efficacy of novel agents, the role of hematopoietic cell transplantation (HCT) in MM remains under scrutiny. Rapid advances in myeloma immunotherapy including the recent approval of chimeric antigen receptor (CAR) T-cell therapy will impact the MM therapeutic landscape. The American Society for Transplantation and Cellular Therapy convened an expert panel to formulate clinical practice recommendations for role, timing, and sequencing of autologous (auto-HCT), allogeneic (allo-HCT) and CAR T-cell therapy for patients with newly diagnosed (NDMM) and relapsed/refractory MM (RRMM). The RAND-modified Delphi method was used to generate consensus statements. Twenty consensus statements were generated. The panel endorsed continued use of auto-HCT consolidation for patients with NDMM as a standard-of-care option, whereas in the front line allo-HCT and CAR-T were not recommended outside the setting of clinical trial. For patients not undergoing auto-HCT upfront, the panel recommended its use in first relapse. Lenalidomide as a single agent was recommended for maintenance especially for standard risk patients. In the RRMM setting, the panel recommended the use of CAR-T in patients with 4 or more prior lines of therapy. The panel encouraged allo-HCT in RRMM setting only in the context of clinical trial. The panel found RAND-modified Delphi methodology effective in providing a formal framework for developing consensus recommendations for the timing and sequence of cellular therapies for MM.

Role of Stem Cell Transplantation in Multiple Myeloma

Autologous stem cell transplantation (auto-SCT) has been the standard of care in eligible newly diagnosed multiple myeloma (MM) patients. Outcomes of patients with MM have improved significantly due to the advent of several novel drugs. Upfront use of these drugs in induction therapy has significantly increased the rate and depth of responses that have translated into longer remission and survival. This has now raised a debate regarding the role and relevance of auto-SCT in the management of myeloma. However, clinical trials have confirmed the utility of auto-SCT even in the era of novel drugs. Tandem auto-SCT followed by maintenance has shown a progression-free survival (PFS) benefit in high-risk MM, and hence can be considered in young and fit patients with high-risk disease. Auto-SCT has the advantages of resetting the bone marrow microenvironment, short-lived toxicity compared to the long-term physical and financial toxicities of continued chemotherapy in the absence of SCT, very low transplant-related mortality (TRM) in high volume centers, and providing longer disease-free survival when followed by maintenance therapy. Allogeneic SCT is one potentially curative option for MM, albeit with an increased risk of death due to high TRM. Strategies to modulate the graft-versus-host disease (GVHD) while maintaining or improving the graft-versus-myeloma (GVM) effect could place allogeneic SCT back in the treatment armamentarium of MM.

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.

Allogenic stem cell transplantation in multiple myeloma: dead or alive and kicking?

Multiple myeloma (MM) accounts for about 1.8% of all cancers and slightly over 17% of hematologic malignancies. Despite improvements in outcomes in recent years, currently, there is still no cure for this disease. Although allogeneic stem cell transplantation (Allo-SCT) is a potentially curative treatment, given the armamentarium of highly effective therapeutic options and a pipeline of novel agents, many opinion leaders sustain that there is no longer a role for this approach. Of note, several studies that did not include novel agents reported long-term molecular remissions, and possibly a cure, in a subset of patients after reduced-intensity conditioning/nonmyeloablative (RIC/NM) Allo-SCT. However, there are no current data supporting upfront Allo-SCT. Prospective trials combining the so-called "graft-versus-myeloma" effect and new drugs are an unmet medical need in high-risk patients. Early relapse after first-line treatment, which identifies patients with poor prognosis independently of other prognostic factors, could become a clinical indication.

Chimeric antigen receptor T cell therapy in multiple myeloma: promise and challenges

Despite a sea change in the therapeutic landscape, multiple myeloma (MM), a cancer of antibody producing plasma cells, remains incurable requiring continued intervention for disease control. In this context, chimeric antigen receptor (CAR) T cell therapy has emerged as a promising immunotherapeutic approach with unprecedented results in heavily treated relapsed and/or refractory MM patients. Although B cell maturation antigen (BCMA) is the current lead target for CAR-T cell therapy in MM, several other antigenic targets are also being investigated. Relapses, however, are inevitable in spite of the promising early responses, and may be mediated by antigenic modulation, poor persistence and "immunostat" in tumor microenvironment. Akin to multi-agent chemotherapy, multi-targeted CAR-T antigens and combinatorial approaches are underway to overcome the resistance mechanisms. Further, CAR-T specific toxicity concerns such as cytokine release syndrome and neurotoxicity, as well as manufacturing time lag are other key challenges. Allogeneic CAR that offers "off-the-shelf" options, and mRNA transfected CAR are being developed to mitigate the access and safety issues. In this review we provide the comprehensive review of the most current clinical trial data for CAR-T in myeloma, challenges associated with this therapy and discuss its future in myeloma therapeutics.

Long-term follow up of tandem autologous-allogeneic hematopoietic cell transplantation for multiple myeloma

We previously reported initial results in 102 multiple myeloma (MM) patients treated with sequential high-dose melphalan and autologous hematopoietic cell transplantation followed by 200 cGy total body irradiation with or without fludarabine 90 mg/m² and allogeneic hematopoietic cell transplantation. Here we present long-term clinical outcomes among the 102 initial patients and among 142 additional patients, with a median follow up of 8.3 (range 1.0-18.1) years. Donors included human leukocyte antigen identical siblings (n=179) and HLA-matched unrelated donors (n=65). A total of 209 patients (86%) received tandem autologous-allogeneic upfront, while thirty-five patients (14%) had failed a previous autologous hematopoietic cell transplantation before the planned autologous-allogeneic transplantation. Thirty-one patients received maintenance treatment at a median of 86 days (range, 61-150) after allogeneic transplantation. Five-year rates of overall survival (OS) and progression-free survival (PFS) were 54% and 31%, respectively. Ten-year OS and PFS were 41% and 19%, respectively. Overall non-relapse mortality was 2% at 100 days and 14% at five years. Patients with induction-refractory disease and those with high-risk biological features experienced shorter OS and PFS. A total of 152 patients experienced disease relapse and 117 of those received salvage treatment. Eighty-three of the 117 patients achieved a clinical response, and for those, the median duration of survival after relapse was 7.8 years. Moreover, a subset of patients who became negative for minimal residual disease (MRD) by flow cytometry experienced a significantly lower relapse rate as compared with MRD-positive patients (P=0.03). Our study showed that the graft-versus-myeloma effect after non-myeloablative allografting allowed long-term disease control in standard and high-risk patient subsets. Ultra-high-risk patients did not appear to benefit from tandem autologous/allogeneic hematopoietic cell transplantation because of early disease relapse. Incorporation of newer anti-MM agents into the initial induction treatments before tandem hematopoietic cell transplantation and during maintenance might improve outcomes of ultra-high-risk patients. Clinical trials included in this study are registered at: clinicaltrials.gov identifiers: 00075478, 00005799, 01251575, 00078858, 00105001, 00027820, 00089011, 00003196, 00006251, 00793572, 00054353, 00014235, 00003954.

Proceedings From the Fourth Haploidentical Stem Cell Transplantation Symposium (HAPLO2016), San Diego, California, December 1, 2016

The resurgence of haploidentical stem cell transplantation (HaploSCT) over the last decade is one of the most important advances in the field of hematopoietic stem cell transplantation (HSCT). The modified platforms of T cell depletion either ex vivo (CD34+ cell selection, "megadoses" of purified CD34+ cells, or selective depletion of T cells) or newer platforms of in vivo depletion of T cells, with either post-transplantation high-dose cyclophosphamide or intensified immune suppression, have contributed to better outcomes, with survival similar to that in HLA-matched donor transplantation. Further efforts are underway to control viral reactivation using modified T cells, improve immunologic reconstitution, and decrease the relapse rate post-transplantation using donor-derived cellular therapy products, such as genetically modified donor lymphocytes and natural killer cells. Improvements in treatment-related mortality have allowed the extension of haploidentical donor transplants to patients with hemoglobinopathies, such as thalassemia and sickle cell disease, and the possible development of platforms for immunotherapy in solid tumors. Moreover, combining HSCT from a related donor with solid organ transplantation could allow early tapering of immunosuppression in recipients of solid organ transplants and hopefully prevent organ rejection in this setting. This symposium summarizes some of the most important recent advances in HaploSCT and provides a glimpse in the future of fast growing field.

Haploidentical Allogeneic Hematopoietic Cell Transplantation for Multiple Myeloma Using Post-Transplantation Cyclophosphamide Graft-versus-Host Disease Prophylaxis

Allogeneic (allo) hematopoietic cell transplantation (HCT) currently represents the only potentially curative therapy for patients affected by multiple myeloma (MM). Up to 30% of patients in western countries do not have a matched donor. Haploidentical HCT (haplo-HCT) may be an option, but currently, there are little available data regarding this treatment. We analyzed survival outcomes of 30 heavily pretreated MM patients who received haplo-HCT with post-transplantation cyclophosphamide as graft-versus-host-disease (GVHD) prophylaxis. Median neutrophil and platelet engraftments at day +30 were 87% (95% confidence interval [CI], 66% to 95%) and 60% (95% CI, 40% to 75%), respectively. The cumulative incidences of relapse or progression of disease (PD) and nonrelapse mortality at 18 months were 42% (95% CI, 23% to 59%) and 10% (95% CI, 2% to 24%), respectively. The cumulative incidence of grade II to IV acute GVHD at day +100 was 29% (95% CI, 14% to 47%). The cumulative incidence of chronic GVHD at 18 months was 7% (95% CI, 1% to 21%). With a median follow-up in survivors of 25 months (range, 15 to 73 months), the 18-month progression-free survival (PFS) and overall survival (OS) were 33% (95% CI, 17% to 50%) and 63% (95% CI, 44% to 78%), respectively. No differences were observed between peripheral blood and bone marrow graft in terms of engraftment, GVHD, or PD incidence. Chemorefractory disease at transplantation was associated with a lower/reduced 18-month PFS (9% versus 47%, P = .01) and OS (45% versus 74%, P = .03). This was explained by a higher PD incidence (55% versus 33%, P = .05). In this multicenter study, we report encouraging results with haplo-HCT for patients with heavily pretreated MM.

Moving Beyond Autologous Transplantation in Multiple Myeloma: Consolidation, Maintenance, Allogeneic Transplant, and Immune Therapy

For multiple myeloma, introduction of novel agents as part of the front-line treatment followed by high-dose chemotherapy and autologous hematopoietic stem cell transplantation (ASCT) induces deep responses in a majority of patients with this disease. However, disease relapse is inevitable, and, with each relapse, the remission duration becomes shorter, ultimately leading to a refractory disease. Consolidation and maintenance strategy after ASCT is one route to provide sustained disease control and prevent repeated relapses. Though the consolidation strategy remains largely confined to clinical trials, significant data support the efficacy of consolidation in improving the depth of response and outcomes. There are also increasing rates of minimal residual disease-negativity with additional consolidation therapy. On the other hand, maintenance with novel agents post-transplant is well established and has been shown to improve both progression-free and overall survival. Evolving paradigms in maintenance include the use of newer proteasome inhibitors, immunotherapy maintenance, and patient-specific maintenance-a concept that utilizes minimal residual disease as the primary driver of decisions regarding starting or continuing maintenance therapy. The other approach to overcome residual disease is immune therapeutic strategies. The demonstration of myeloma-specific alloimmunity from allogeneic transplantation is well established. More sophisticated and promising immune approaches include adoptive cellular therapies, tumor vaccines, and immune checkpoint manipulations. In the future, personalized minimal residual disease-driven treatment strategies following ASCT will help overcome the residual disease, restore multiple myeloma-specific immunity, and achieve sustained disease control while minimizing the risk of overtreatment.

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.

Pushing the envelope-nonmyeloablative and reduced intensity preparative regimens for allogeneic hematopoietic transplantation

Allogeneic hematopoietic cell transplantation (HCT) was originally developed to allow delivery of myeloablative doses of chemotherapy and radiotherapy. With better understanding of disease pathophysiology, the graft vs malignancy (GVM) effect of allogeneic hematopoietic transplantation and toxicities associated with myeloablative conditioning (MAC) regimens, the focus shifted to developing less toxic conditioning regimens to reduce treatment-related morbidity without compromising survival. Although HCT with MAC is preferred to reduced intensity conditioning (RIC) for most patients ⩽60 years with AML/myelodysplastic syndrome and ALL, RIC and nonmyeloablative (NMA) regimens allow HCT for many otherwise ineligible patients. Reduced intensity preparative regimens have produced high rates of PFS for diagnoses, which are highly sensitive to GVM. Relapse of the malignancy is the major cause of treatment failure with RIC/NMA HCT. Incorporation of novel agents like bortezomib or lenalidomide, addition of cellular immunotherapy and use of targeted radiation therapies could further improve outcome. In this review, we discuss commonly used RIC/NMA regimens and promising novel regimens.

Multiple myeloma

Autologous stem cell transplant (ASCT) remains an integral part of the treatment strategy for many myeloma patients. The role of allogeneic stem cell transplant continues to be defined. There is increasing evidence that posttransplant maintenance therapy can significantly improve outcomes. It is predicted that with more routine use of cytogenetic and gene expression profiling in the future, we will be better able to identify those subgroups of patients who are expected to benefit most from early versus late versus no ASCT and those who will benefit from allogeneic stem cell transplant.

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.

Second transplants for multiple myeloma relapsing after a previous autotransplant-reduced-intensity allogeneic vs autologous transplantation

There is no standard therapy for multiple myeloma relapsing after an autotransplant. We compared the outcomes of a second autotransplant (N=137) with those of an allotransplant (N=152) after non-myeloablative or reduced-intensity conditioning (NST/RIC) in 289 subjects reported to the CIBMTR from 1995 to 2008. NST/RIC recipients were younger (median age 53 vs 56 years; P<0.001) and had a shorter time to progression after their first autotransplant. Non-relapse mortality at 1-year post transplant was higher in the NST/RIC cohort, 13% (95% confidence interval (CI), 8-19) vs 2% (95% CI, 1-5, P0.001). Three-year PFS and OS for the NST/RIC cohort were 6% (95% CI, 3-10%) and 20% (95% CI, 14-27%). Similar outcomes for the autotransplant cohort were 12% (95% CI, 7-19%, P=0.038) and 46% (95% CI, 37-55%, P=0.001). In multivariate analyses, risk of death was higher in NST/RIC recipients (hazard ratio (HR) 2.38 (95% CI, 1.79-3.16), P<0.001), those with Karnofsky performance score<90 (HR 1.96 (95% CI, 1.47-2.62), P<0.001) and transplant before 2004 (HR 1.77 (95% CI, 1.34-2.35) P0.001). In conclusion, NST/RIC was associated with higher TRM and lower survival than an autotransplant. As disease status was not available for most allotransplant recipients, it is not possible to determine which type of transplant is superior after autotransplant failure.

Impact of high-risk cytogenetics and achievement of molecular remission on long-term freedom from disease after autologous-allogeneic tandem transplantation in patients with multiple myeloma

Within a prospective protocol, the incidence and impact of achievement of molecular remission (mCR) and high-risk cytogenetics was investigated in 73 patients with multiple myeloma (MM) after autologous (auto)-allogeneic (allo) tandem stem cell transplantation (SCT). After induction chemotherapy, patients received melphalan 200 mg/m(2) before undergoing auto-SCT, followed 3 months later by melphalan 140 mg/m(2) and fludarabine 180 mg/m(2) before allo-SCT. Sixteen patients had high-risk cytogenetic features, defined by positive FISH for del(17p13) and/or t(4;14). Overall, 66% of the patients achieved CR or near-CR, and 41% achieved mCR, which was sustained negative (at least 4 consecutive samples negative) in 15 patients (21%), with no significant difference in incidence between the patients with high-risk cytogenetics and others (P = .70). After a median follow-up of 6 years, overall 5-year progression-free survival was 29%, with no significant difference between del 17p13/t(4;14)-harboring patients and others (24% versus 30%; P = .70). The 5-year progression-free survival differed substantially according to the achieved remission: 17% for partial remission, 41% for CR, 57% for mCR, and 85% for sustained mCR. These results suggest that auto-allo tandem SCT may overcome the negative prognostic effect of del(17p13) and/or t(4;14) and that achievement of molecular remission resulted in long-term freedom from disease.

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.

Advances in the autologous and allogeneic transplantation strategies for multiple myeloma

BACKGROUND

Multiple myeloma is largely an incurable malignant plasma cell neoplasm; however, the landscape of its treatment is rapidly changing.

METHODS

The recent literature on both autologous and allogeneic transplant approaches for multiple myeloma was reviewed.

RESULTS

High-dose chemotherapy followed by autologous hematopoietic cell transplantation (HCT) remains an integral component of upfront treatment strategy, and the incorporation of novel immunomodulators and proteasome inhibitor to induction regimens improves response rates and increases overall survivals. Bortezomib and lenalidomide-based combination chemotherapy regimens have become the standard induction myeloma therapy. When myeloma patients proceed to transplant after novel combination regimens, their response rates are further improved. Despite these recent major improvements, myeloma remains incurable and long-term survival appears elusive. Due in part to a potential graft-vs-myeloma effect, allogeneic HCT is a potentially curative transplant option. However, initial attempts have been hampered by the high transplant-related mortality. With a reduction of toxicity, allogeneic transplant approaches with reduced-intensity conditioning have been utilized, although they are subject to continued disease progression and relapse following transplantation. Recent research efforts have shifted to the use of a tandem autologous-allogeneic HCT approach. The long-term follow-up of this new strategy is awaited.

CONCLUSIONS

Recent advances in HCT have improved outcomes of patients with multiple myeloma. Ongoing research activity focuses on the strategies to improve outcomes of HCT by incorporation of tandem autologous-allogeneic transplantation schema, novel conditioning regimens, and the use of consolidation and maintenance therapy.

Significant oral graft-versus-host disease after allogeneic stem cell transplantation with the FLU/MEL conditioning regimen

Background

Oral graft-versus-host disease (GVHD) is a significant complication after allogeneic stem cell transplantation (SCT) and there is no consistent information about its characteristics in patients after reduced-intensity conditioning regimen FLU/MEL (fludarabine 120 mg/m² and melphalan 140mg/m²).

Material/Methods

This was a single-centre prospective observational study of patients after allogeneic SCT with FLU/MEL conditioning performed during the period 1/2005-12/2007. Characteristics of oral GVHD were observed in 71 patients. The observation was discontinued due to death, donor lymphocyte infusion (DLI) or new chemotherapy administration.

Results

In 10/2010, the median duration of the observation of the cohort of the patients was 13 (0.2–69) months, and 42 (35–69) months in the still-ongoing 20/71 (28%) patients. Oral acute GVHD had sporadic 7% incidence, whereas oral chronic GVHD was observed in 33% of patients and persisted with median duration of 188 (11–665) days. Clinical and histopathological features were similar in both acute and chronic oral GVHD and included mucosal lichenoid changes, erythema, ulcerations and pseudomembranes, satellite necrosis, apoptotic bodies and lichenoid interface inflammation.

Conclusions

It is necessary to consider complex clinical symptomatology and pathological correlations when classifying the oral GVHD, because local oral symptoms and histopathological features in both acute and chronic oral GVHD forms can be similar. Even though the oral chronic GVHD was mild in the majority of patients, it can be considered as clinically significant due to its incidence, duration and symptomatology. The FLU/MEL conditioning regimen should not be considered as low-risk protocol in this context.

Younger donor's age and upfront tandem are two independent prognostic factors for survival in multiple myeloma patients treated by tandem autologous-allogeneic stem cell transplantation: a retrospective study from the Société Française de Greffe de Moelle et de Thérapie Cellulaire (SFGM-TC)

BACKGROUND

How tandem autologous-allogeneic stem cell transplantation should be integrated in the treatment of multiple myeloma remains controversial. We examined the long-term outcome of patients with multiple myeloma managed with tandem autologous-allogeneic stem cell transplantation and present a prognostic factor analysis based on the experience of the Société Française de Greffe de Moelle et de Thérapie Cellulaire (SFGM-TC).

DESIGN AND METHODS

This French, retrospective, registry-based study included 146 patients who had undergone tandem autologous-allogeneic transplantation for multiple myeloma at 20 SFGM-TC centers between 1998 and 2010. The patients included in the study had fully completed the two steps of a planned tandem autologous-allogeneic transplantation. No treatment had to be administered between the autologous and allogeneic parts of the tandem procedure.

RESULTS

Seventy-seven patients (53%) underwent tandem autologous-allogeneic transplantation as part of upfront treatment, i.e. after a single line of treatment not including autologous transplantation. The median follow-up from the allogeneic transplant was 47.5 months (range, 1.2-132 months). At 4 years, the overall survival and event-free survival rates were 48% (95% CI 39-57 %) and 27% (95% CI 19-36), respectively. Eighteen patients (12%) experienced grade III-IV acute graft-versus-host disease and 43 patients (30%) had chronic graft-versus-host disease. The transplant-related mortality rate at 1 year was 15% (95% CI 10-22). Patients receiving tandem transplantation as upfront treatment had significantly improved event-free survival (36% versus 11%; P=0.005) and overall survival (56% versus 34%; P=0.02). Donor's age ≤ 50 years was associated with improved event-free survival (35% versus 16%; P=0.005) and overall survival (54% versus 41%; P=0.02). In the multivariable analysis, upfront tandem transplantation, donor's age ≤ 50 years and full chimerism were independent prognostic factors for better outcome.

CONCLUSIONS

We confirmed the feasibility of tandem autologour-allogeneic transplantation in heavily treated patients with multiple myeloma. We identified younger donor's age and upfront tandem transplantation as two independent prognostic factors for survival which could be further explored in prospective studies.

Allogeneic stem cell transplantation in multiple myeloma relapsed after autograft: a multicenter retrospective study based on donor availability

Allogeneic stem cell transplantation (allo-SCT) using reduced-intensity conditioning (RIC) is a feasible procedure in selected patients with relapsed multiple myeloma (MM), but its efficacy remains a matter of debate. The mortality and morbidity related to the procedure and the rather high relapse risk make the use of allo-SCT controversial. In addition, the availability of novel antimyeloma treatments, such as bortezomib and immunomodulatory agents, have made allo-SCT less appealing to clinicians. We investigated the role of RIC allo-SCT in patients with MM who relapsed after autologous stem cell transplantation and were then treated with a salvage therapy based on novel agents. This study was structured similarly to an intention-to-treat analysis and included only those patients who underwent HLA typing immediately after the relapse. Patients with a donor (donor group) and those without a suitable donor (no-donor group) were compared. A total of 169 consecutive patients were evaluated retrospectively in a multicenter study. Of these, 75 patients found a donor and 68 (91%) underwent RIC allo-SCT, including 24 from an HLA-identical sibling (35%) and 44 from an unrelated donor (65%). Seven patients with a donor did not undergo allo-SCT for progressive disease or concomitant severe comorbidities. The 2-year cumulative incidence of nonrelapse mortality was 22% in the donor group and 1% in the no-donor group (P < .0001). The 2-year progression-free survival (PFS) was 42% in the donor group and 18% in the no-donor group (P < .0001). The 2-year overall survival (OS) was 54% in the donor group and 53% in the no-donor group (P = .329). In multivariate analysis, lack of a donor was a significant unfavorable factor for PFS, but not for OS. Lack of chemosensitivity after salvage treatment and high-risk karyotype at diagnosis significantly shortened OS. In patients who underwent allo-SCT, the development of chronic graft-versus-host disease had a significant protective effect on OS. This study provides evidence for a significant PFS benefit of salvage treatment with novel drugs followed by RIC allo-SCT in patients with relapsed MM who have a suitable donor.

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.

Unrelated stem cell transplantation for patients with multiple myeloma

PURPOSE OF REVIEW

The role of allogeneic stem cell transplantation (SCT) in treatment of myeloma patients is still controversial. Meanwhile, the numbers of unrelated SCT for hematological diseases in Europe are higher than for human leukocyte antigen (HLA)-identical sibling transplantations, but in multiple myeloma only 39% of the allogeneic transplantations are performed from unrelated donors and only a minority were done within prospective clinical trials.

RECENT FINDINGS

The few published data of unrelated SCT in multiple myeloma reported a higher treatment-related mortality for standard myeloablative conditioning in comparison to reduced-intensity conditioning. Despite the heterogeneous patient selection in the trial, lower nonrelapse mortality and improved survival can be achieved by careful donor selection (10/10 HLA-alleles, male donor). Natural killer-alloreactivity might play a role, but conclusive data are lacking. Transplantation in more advanced or refractory patients is associated with an inferior outcome. The results of an unrelated SCT seem to be comparable to those of HLA-identical siblings, but a direct comparison is lacking so far.

SUMMARY

Unrelated SCT in multiple myeloma is feasible, but prospective clinical trials using unrelated stem cell donors are urgently needed to define the role of an unrelated SCT in multiple myeloma in the era of novel agents.

Clinical impact of chromosomal aberrations in multiple myeloma

Chromosomal aberrations are frequently found in multiple myeloma cells and play a major role in patient outcome and management of the disease. The most important chromosomal aberrations associated with poor outcome are del(17p), t(4;14), t(14;16) and t(14;20). Others that may be associated with adverse prognosis include amp(1)(q21), del(1p32), del(13), del(8p21) and hypodiploidy. Many chromosomal aberrations have no or uncertain impact; for example, t(11;14), t(8;14) and hyperdiploidy. Attempts have been made to overcome the negative prognostic impact of chromosomal aberrations using autologous or allogeneic transplantation or new immunomodulatory drugs such as thalidomide, lenalidomide and the proteasome inhibitor bortezomib, but the results are controversial. Data suggest that allogeneic transplantation and treatment with bortezomib or lenalidomide may help to overcome the negative effect of del(13) on prognosis, whereas bortezomib may have some influence on reducing the impact of del(17p), t(4;14) and t(14;16). Chromosome analysis should always be performed at diagnosis of multiple myeloma to improve the prediction of outcome and to aid treatment decision-making.

Therapy of relapsed and refractory multiple myeloma

Despite considerable improvements in first line treatment still the majority of patients experience relapse of multiple myeloma. Treatment decisions for relapse or refractory multiple myeloma should be based on a clinical decision path taking response and adverse events to previous therapy, myeloma specific complications and organ dysfunctions, overall clinical condition, age, cytogenetic information and prognostic factors into account. Bortezomib, thalidomide and lenalidomide have improved the therapeutic armentarium for patients with refractory or relapsed disease and are often used in combination with dexamethasone or chemotherapeutic agents. Combination therapies of novel agents in drug combination regimen are currently under investigation as well. For patients with a disease free survival of 12 month or longer after initial single or tandem high dose therapy and autologous stem cell transplantation (ASCT) repeat of high dose therapy with melphalan and ASCT should be considered in case of relapse. Radiotherapy and osteoplastic procedures can be used as adjunct to systemic therapy to treat local complications in particular vertebral pain caused by osteolytic bone disease. Cytogenetic tests, molecular techniques as gene expression profiling and other diagnostic will lead to a more individualized therapy. The integration of novel compounds into established regimen will be a major challenge for future clinical studies.

High complete remission rate and durable remissions achieved with rational use of autologous stem-cell transplantation, thalidomide maintenance, and non-myeloablative allogeneic transplantation in patients with multiple myeloma

Autologous stem-cell transplantation (ASCT) has emerged as the standard approach in patients with multiple myeloma, although it is unlikely to achieve cure. Thalidomide maintenance and non-myeloablative allogeneic transplantation (NST) may increase complete remission (CR) rate and increase overall survival. In this study, 35 ASCT and 10 NST were performed in 33 patients. Patients, who were resistant or relapsed following ASCT, underwent NST if they had an HLA-matched sibling, otherwise treated with a second ASCT. Thalidomide was started as maintenance after ASCT. After first transplantation, three patients underwent second ASCT and 10 patients underwent NST. Following first transplantation, CR rate was 39% and increased to 60% (overall response 93%) with addition of thalidomide, bortezomib, and second transplantation. CR was durable in 14 (42%) patients. During a median follow-up of 24 months, 18 patients progressed and nine patients died. The 100-d transplant-related mortality was <5%. The four-yr progression-free survival (PFS) was 52.4%. In conclusion, ASCT followed by thalidomide and NST in resistant patients can lead to high CR and PFS rates. As a second transplantation has not been performed routinely, patients having durable CR had a chance to avoid or delay a second transplantation without compromising disease control.

Treatment of relapsed and refractory multiple myeloma in the era of novel agents

The introduction of the Immunomodulatory drugs (IMiDs) and proteasome inhibitors, used either as a single-agent or combined with classic anti-myeloma therapies, has improved the outcome for patients with relapsed myeloma. However, there is currently no generally accepted standard treatment for relapsed/refractory myeloma patients, partly because of the absence of trials comparing the efficacy of the novel agents in relapsed/refractory myeloma. Choice of a new treatment regimen depends on both patient and disease-specific characteristics. A lenalidomide-based regimen is the first choice in patients with neuropathy, while bortezomib has the highest efficacy in patients with renal insufficiency and is not associated with increased risk of thromboembolism. A second autologous stem cell transplantation (auto-SCT) can be applied in patients with a progression-free period of ≥ 18-24 months after the first auto-SCT. In high-risk relapse such as occurring early after auto-SCT consolidation with allogeneic SCT can be considered. In this review we provide an overview of the various salvage regimens and give recommendations for treatment of patients with relapsed/refractory myeloma in different clinical settings.

EPOCH-F: a novel salvage regimen for multiple myeloma before reduced-intensity allogeneic hematopoietic SCT

There exists a need for effective salvage regimens for multiple myeloma patients being considered for reduced-intensity allogeneic hematopoietic SCT (RI-alloHSCT). We developed EPOCH-F, a regimen consisting of infusional etoposide, VCR and adriamycin with prednisone, CY and fludarabine to achieve both tumor control and host lymphocyte depletion to facilitate engraftment before RI-alloHSCT. In all, 22 multiple myeloma patients were treated with EPOCH-F before RI-alloHSCT. The median age was 53 years (range 36-65), and the median number of previous therapies was 2 (range 1-8). Patients received a median of three cycles (range 1-5) of EPOCH-F. Toxicities were primarily hematologic and manageable. Median lymphocyte counts decreased from 1423/μL (range 335-2788) to 519/μL (range 102-1420; P=0.0002). The overall response (≥PR) to EPOCH-F was 22 with 13% achieving a CR/near-complete response (nCR); only 1 patient progressed while on therapy. A total of 20 patients underwent RI-alloHSCT. Median day +100 donor chimerism was 100% (range 60-100). In all, 70% of patients achieved very good partial response or better response after transplant; 40% of patients achieved CR/nCR. TRM at 100 days and 5 years was 5 and 30%, respectively. Median OS after RI-alloHSCT was 46.1 months. EPOCH-F provides disease control and host lymphocyte depletion with consistent full donor engraftment in multiple myeloma patients undergoing RI-alloHSCT.

Role of allogeneic transplantation in multiple myeloma in the era of new drugs

High-dose melphalan with autologous stem cell rescue has been regarded as the standard of care for patients with newly diagnosed myeloma up to the age of 65–70 years. The recent development of agents with potent anti-tumor activity such as thalidomide, lenalidomide and bortezomib has further improved overall survival and response rates. However, relapse is a continuous risk.

Allografting is a potentially curative treatment for a subset of multiple myeloma patients for its well documented graft-vs-myeloma effects. However, its role has been hotly debated. Even though molecular remissions have been reported up to 50% after high-dose myeloablative conditionings, their applications, given the high toxicity, have been for long limited to younger relapsed/refractory patients. These limitations have greatly been reduced through the introduction of non-myeloablative/reduced-intensity conditionings.

The introduction of new drugs, characterised by low risks of early mortality, indeed requires to define role and timing of an allograft to capture the subset of patients who may most benefit from graft-vs-myeloma effects.

Ultimately, new drugs should not be viewed as mutually exclusive with an allograft. They may be employed to achieve profound cytoreduction before and enhance graft-versus-myeloma effects as consolidation/maintenance therapy after an allograft. However, this combination should be explored only in well-designed clinical trials.

Non-myeloablative conditioning and allogeneic transplantation for multiple myeloma

In multiple myeloma (MM), allogeneic stem cell transplantation (alloHCT) carries a lower relapse risk than autologous transplantation but a greater transplant-related mortality. Nonmyeloablative conditioning for allogeneic transplantation (NST) reduces transplant-related toxicity. Results are encouraging when used during first remission in low-risk patients, but less-so in relapsed or refractory disease. This is a single-center retrospective analysis of 20 previously treated MM patients who underwent NST from matched-related or matched-unrelated donors from 2000-2006. Median age was 52.7 years (37.2-68.0). Twenty-five percent had advanced or high-risk disease. Eleven still had active disease prior to NST. Conditioning was total body irradiation 200 cGy on a single fraction on day -5, followed by antithymocyte globulin (ATG) 1.5 mg/kg/day and fludarabine 30 mg/m(2)/day on days -4 to -2. All received immunosuppression, most commonly with oral mycofenylate mofetil and cyclosporine beginning on day -5. At day 100, 50% had achieved complete remission. Transplant-related mortality was 25%. Median overall survival (OS) was 21.2 months (0.6-90+) and progression-free survival (PFS) 6.6 months (0.6-90+). Both OS and PFS were 24% at 3 years. OS was significantly greater for patients with age <52 years (median 27 months vs. 7.9 months, P = 0.031), and there was a trend toward greater OS for those with beta2 microglobulin <2.5 mg/l (median 27 months vs. 7.7 months, P = 0.08). Donor characteristics and Ig type had no significant effect on survival. These data suggest a benefit of NST in relapsed/refractory MM. Randomized trials must be performed to confirm and further qualify this benefit.

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.

Reduced-intensity allogeneic hematopoietic stem cell transplantation for relapsed multiple myeloma

Despite recent advances, multiple myeloma (MM) remains incurable, and most patients eventually develop progressive disease. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) offers a potentially curative option in 10%-20% of patients with relapsed or refractory disease. We evaluated the outcome of patients undergoing allo-HSCT with reduced-intensity conditioning (RIC) for relapsed and/or refractory MM at our institution. The study cohort included 51 patients with heavily pretreated, relapsed MM who underwent RIC allo-HSCT between 1996 and 2006. The median time from diagnosis to allo-HSCT was 34 months, and median follow-up in surviving patients was 27 months (range, 3-98 months). Cumulative transplantation-related mortality at 1 year was 25%. Progression-free survival (PFS) and overall survival (OS) at 2 years were 19% and 32%, respectively. The incidences of grade II-IV acute and chronic graft-versus-host disease were 27% and 47%, respectively. At the time of this analysis, 12 patients (24%) were alive, 7 of whom (14%) were in remission for up to 6 years after allo-HSCT. A lower beta2 microglobulin level (<3.3) and previous autologous HSCT were predictive of lower nonrelapse mortality and longer PFS and OS. Our findings indicate that allo-HSCT with RIC is associated with acceptable toxicity and durable remission and survival in relapsed or refractory MM. The use of RIC allo-HSCT earlier in the course of the disease may offer the greatest benefit.