Allogeneic transplantation in multiple myeloma: long-term follow-up and cytogenetic subgroup analysis

Autologous followed by allogeneic versus tandem-autologous transplantation in high-risk, newly diagnosed multiple myeloma: a systematic review and meta-analysis

OBJECTIVES

High-risk multiple myeloma (HRMM) is associated with poor survival, despite many advances in antimyeloma strategies. Autologous followed by allogeneic stem cell transplantation (auto-allo-SCT) has yielded controversial results compared to tandem autologous stem cell transplantation (auto-SCT) in patients with HRMM. We conducted this meta-analysis to compare the efficacy and safety of auto-allo-SCT and tandem-auto-SCT in patients with HRMM.

METHODS

Embase, Cochrane Library, and PubMed databases were searched until March 2023. Prospective or retrospective studies comparing the effects of auto-allo-SCT and tandem-auto-SCT were included. Hazard ratios (HRs) and 95% confidence intervals (CIs) for time-to-event outcomes, and odds ratios (ORs) and 95%CIs for dichotomous outcomes were pooled using random-effects models.

RESULTS

Three studies involving 491 patients were included. Despite auto-allo-SCT seemed to be associated with improvements in progression-free survival (PFS) (HR [95%CI], 0.71 [0.51-1.00]) and complete response (CR) (OR [95%CI], 3.16 [1.67-5.99]), and reduced relapse/progression rates (47% vs. 55%) in comparison with tandem-auto-SCT, no marked improvement in overall survival (OS). In comparison to tandem-auto-SCT, patients assigned to auto-allo-SCT exhibited a higher risk of transplant-related mortality (TRM) (11.9% vs. 4.1%) and non-relapse mortality (NRM) (12.3% vs. 3.1%).

CONCLUSION

Auto-allo-SCT seemed to be associated with improvements in PFS and CR when compared to tandem-auto-SCT in patients with HRMM, but it did not lead to a significant improvement in OS. Furthermore, patients in the auto-allo-SCT group were at a higher risk of developing TRM and NRM. Auto-allo-SCT transplantation should not be routinely incorporated into HRMM therapy but rather should be considered investigational.

Experts' consensus on the definition and management of high risk multiple myeloma

High risk multiple myeloma (HRMM) at diagnosis is currently recognized according to the Revised International Staging System (R-ISS) which was set up in 2015. Since then, new clinical and biological prognostic factors have been developed, which could implement the definition of High Risk (HR) category. We conducted a survey in order to identify which additional parameters, both clinical and biological, are considered more useful for the clinical practice and to evaluate if the management of Multiple Myeloma (MM) should change on the basis of the risk category. A questionnaire, consisting of 8 statements, was submitted to 6 Italian experts, from the European Myeloma Network (EMN) Research Italy, using the Delphi method. The colleagues were asked to answer each question using a scale between 0 and 100. If a statement did not reach at least 75 out of 100 points from all the participants, it was rephrased on the basis of the proposal of the experts and resubmitted in a second or further round, until a consensus was reached among all. From the first round of the survey a strong consensus was reached regarding the opportunity to revise the R-ISS including chromosome 1 abnormality, TP53 mutation or deletion, circulating plasma cells by next generation flow and extramedullary plasmacytomas. No consensus was reached for the definition of "double hit" MM and for the application in clinical practice of treatment strategies based on the risk category. In the second round of the Delphi questionnaire, "double-hit" MM was recognized by the association of at least two high-risk cytogenetic or molecular abnormalities. Moreover, the experts agreed to reserve an intensified treatment only to specific conditions, such as plasma cell leukaemia or patients with multiple extramedullary plasmacytomas, while they admitted that there are not sufficient real word data in order to modify treatment on the basis of MRD assessment in clinical practice. This survey suggests that the definition of HRMM should be implemented by additional clinical and biological risk factors, that will be useful to guide treatment in the future.

How to Manage Patients with Lenalidomide-Refractory Multiple Myeloma

Although lenalidomide-based combinations, such as lenalidomide plus a proteasome inhibitor or an anti-CD38 monoclonal antibody, improve the overall response rate, progression-free survival, and overall survival of patients with relapsed/refractory multiple myeloma (RRMM), there is a tendency to use these regimens as a frontline treatment. This strategy has led to the development of refractoriness early in the disease course, usually after the patient's first treatment. Since lenalidomide-free regimens have so far shown limited efficacy in lenalidomide-refractory patients, there is an unmet need for other treatment options. In this review, we discuss the therapeutic options available to treat the general population of lenalidomide-refractory patients (mono, double and triple refractory) and the subpopulation of patients with other high-risk features such as renal failure, extramedullary disease, and high-risk cytogenetics. Moreover, new promising individual therapies and the possible impact of immunotherapy in RRMM patients are debated.

Prognostic Value of Association of Copy Number Alterations and Cell-Surface Expression Markers in Newly Diagnosed Multiple Myeloma Patients

Multiple myeloma results from the clonal proliferation of abnormal plasma cells (PCs) in the bone marrow (BM). In this study, the cell surface expression markers (CD) on atypical PCs (detected by multiparametric flow cytometry (MFC)) were correlated with copy number alterations (CNAs) in the genome (detected by multiplex ligation-dependent probe amplification (MLPA)) to assess their impact on prognosis in newly diagnosed MM patients. Statistically significant results were obtained when different stages of PC maturation (classified based on CD19 and CD81 expression) were associated with CD117 expression and identified CNAs. In the intermediately differentiated PC group (CD19(−) CD81(+)), patients who didn’t express CD117 had a lower median progression free survival (PFS) (p = 0.024). Moreover, within this group, patients with less than three adverse CNAs, which harbor CD117, had a better outcome with a PFS of more than 48 months compared with 19 months (p = 0.008). Considering all the results, our study suggested the need to integrate both the CD markers and copy number alterations to evaluate the prognosis of newly diagnosed multiple myeloma patients.

Current Role of Allogeneic Stem Cell Transplantation in Multiple Myeloma

Major progress in the treatment of multiple myeloma has been made in the last several years. However, myeloma remains incurable and patients with high-risk cytogenetics or advanced stage disease have an even worsen survival. Only allogeneic transplantation may have curative potential in some patients. However, the high non-relapse mortality and incidence of chronic graft-versus-host disease have raised controversy regarding this procedure. In this review, we will address the role of upfront and delayed allogeneic transplant.

Recommendations on the management of multiple myeloma in 2020

With the introduction of immunomodulatory drugs, proteasome inhibitors, and anti-CD38 monoclonal antibodies, major improvements have been achieved in the treatment of multiple myeloma (MM), with a significant impact on the outcome of this disease. Different treatment combinations are now in use and other therapies are being developed. Based on an extensive review of the recent literature, we propose practical recommendations on myeloma management, to be used by hematologists as a reference for daily practice.

Cellular Immunotherapies for Multiple Myeloma: Current Status, Challenges, and Future Directions

Multiple myeloma (MM) remains incurable due to relapse, although the use of proteasome inhibitors, immunomodulatory drugs, CD38-targeting antibodies, and autologous stem cell transplantation (auto-SCT) significantly improve the clinical outcomes of patients with newly diagnosed MM. In recent years, the introduction of chimeric antigen receptor T-cell (CAR T-cell) therapy has brought hope to patients with refractory and relapsed MM. The graft-versus-myeloma effect of allogeneic SCT provides the possibility for curing a subset of MM patients. In this review, we summarize the recent advances and challenges of cellular immunotherapies for MM, focusing on auto-SCT, allogeneic SCT, and CAR T-cell approaches. We also discuss future directions, and propose a specific algorithm for cellular therapies for MM and probability of minimal residual disease-directed therapy.

Allogeneic Stem Cell Transplantation in Multiple Myeloma

The development of new inhibitory and immunological agents and combination therapies significantly improved response rates and survival of patients diagnosed with multiple myeloma (MM) in the last decade, but the disease is still considered to be incurable by current standards and the prognosis is dismal especially in high-risk groups and in relapsed and/or refractory patients. Allogeneic hematopoietic stem cell transplantation (allo-SCT) may enable long-term survival and even cure for individual patients via an immune-mediated graft-versus-myeloma (GvM) effect, but remains controversial due to relevant transplant-related risks, particularly immunosuppression and graft-versus-host disease, and a substantial non-relapse mortality. The decreased risk of disease progression may outweigh this treatment-related toxicity for young, fit patients in high-risk constellations with otherwise often poor long-term prognosis. Here, allo-SCT should be considered within clinical trials in first-line as part of a tandem approach to separate myeloablation achieved by high-dose chemotherapy with autologous SCT, and following allo-SCT with a reduced-intensity conditioning to minimize treatment-related organ toxicities but allow GvM effect. Our review aims to better define the role of allo-SCT in myeloma treatment particularly in the context of new immunomodulatory approaches.

Outcomes in newly diagnosed young or high-risk myeloma patients receiving tandem autologous/allogeneic transplant followed by bortezomib maintenance: a phase II study

Despite novel drugs and autologous HCT, MM remains incurable, with short survival in patients with poor biological characteristics. Allo HCT may be curative in some patients but is hampered by high rates of toxicity and relapse. We hypothesized that bortezomib (BTZ), with its anti-myeloma and immunologic properties, could improve PFS and cGVHD after allo HCT in newly diagnosed MM patients. In this prospective phase II study, we included 39 young (≤50 years) and high-risk patients who received a tandem auto-allo HCT followed by BTZ. Patients had prospective minimal residual disease (MRD) evaluations using Next-Generation Flow cytometry prior to allo HCT, prior BTZ and every 3 months for 2 years. With a median follow-up of 48 months, we report PFS and OS at 5 years of 41% and 80%, with a non-relapse mortality of 12%. Incidences of grade II-IV aGVHD at 12 months and moderate/severe cGVHD at 2 years were 26% and 57%. In a multivariate analysis model including cytogenetics, ISS and MRD status, MRD positivity prior to allo HCT (HR 3.75, p = 0.037), prior BTZ (HR 11.3, p = 0.018) and 3 months post-BTZ initiation (HR 9.7, p = 0.001) was highly predictive of progression. Peritransplant MRD assessment thus strongly predicts disease progression.

How I Treat High-risk Multiple Myeloma

Survival of multiple myeloma (MM) has significantly improved over the last decade; however, a composed group of patients (15-20%), named high-risk (HR) MM, still experience reduced survival. Both tumor biology and suboptimal/absent responses to therapy may underlie HR definition and a clear uniform identification of risk factors is crucial for a proper management of these patients. In biologic-HRMM, MRD negativity attainment and sustain, inside and outside BM, should be the primary goal and therapy should be adapted in patients with frailty to reduce toxicity and improve quality of life. MM treatment has traditionally been tailored on age and more recently frailty or comorbidities, but very rarely on the biology of the disease, mainly because of the lack of a clear benefit derived from a specific drug/combination, inhomogeneity in HR definition and lack of data coming from prospective, properly designed clinical trials. Some attempts have been successfully made recently in this direction. In this review, we are discussing the current different definitions of HR and the need for a consensus, the results of available trials in HR patients and the way through risk-adapted treatment strategies. For this purpose, we are proposing several clinical cases of difficult-to-treat patients throughout different treatment phases.

Current approaches to management of high-risk multiple myeloma

The median overall survival in multiple myeloma is rapidly approaching 10 years; however, in nearly a fifth of patients the prognosis remains poor. Therefore, the modern-day management of myeloma patients should be individualized, with a more intense and continuous approach in these high-risk patients. This includes first-line treatment based on multi-drug combinations employing the most effective drug combinations, upfront autologous stem cell transplantation (in eligible patients with tandem transplantation being a consideration), and maintenance based on proteasome inhibitor-based combinations. This paper reviews the results of recent retrospective analyses and clinical trials, but also gives a glance into the future by presenting the ongoing trials.

Long-term outcome after allogeneic stem cell transplantation in multiple myeloma

The role of allogeneic hematopoietic stem cell transplantation (allo-SCT) in multiple myeloma is controversial. We analyzed the results of 205 patients transplanted in one center during 2000–2017. Transplantation was performed on 75 patients without a previous autologous SCT (upfront-allo), on 74 as tandem transplant (auto-allo), and on 56 patients after relapse. Median overall survival (OS) was 9.9 years for upfront-allo, 11.2 years for auto-allo, and 3.9 years for the relapse group (p = 0.015). Progression-free survival (PFS) was 2.4, 2.4, and 0.9 years, respectively (p < 0.001). Non-relapse mortality at 5 years was 8% overall, with no significant difference between the groups. Post-relapse survival was 4.1 years for upfront-allo and auto-allo, and 2.6 years for the relapse group (p = 0.066). Survival of high-risk patients was reduced. In multivariate analysis, the auto-allo group had improved OS and chronic graft-versus-host disease was advantageous in terms of PFS, OS, and relapse incidence. Late relapses occurred in all groups. Allo-SCT resulted in long-term survival in a small subgroup of patients. Our results indicate that auto-allo-SCT is feasible and could be considered for younger patients in the upfront setting.

Immunomodulators in newly diagnosed multiple myeloma: current and future concepts

Introduction: Impressive therapeutic progress is being made in the management of multiple myeloma (MM). his progress is related to the introduction of several new classes of therapeutic agents including proteasome inhibitors, immunomodulatory drugs (IMiDs) and monoclonal antibodies (MoAbs).Areas covered: In this manuscript, the role of the IMiDs thalidomide and lenalidomide in the management of newly diagnosed MM is discussed. The mode of action of IMiDs and their role in the management of newly diagnosed MM patients is highlighted. In addition, clinical data on how MoAbs such as the anti-CD38 antibody daratumumab can further increase the efficacy of IMiD-based first-line anti-myeloma regimens are provided. A database search in PubMed was carried out.Expert Opinion: Immunomodulation has become an indispensable part of successful anti-myeloma regimens both at relapse and at diagnosis. The combination of lenalidomide plus dexamethasone with an anti-CD38 MoAb such as daratumumab and a proteasome inhibitor such as bortezomib is currently one of the most potent first-line treatment regimens for MM. A better understanding on how IMiDs synergize with existing and new anti-myeloma treatments can further improve the outcome for patients. Optimal first-line therapy will continue to benefit the long-term outcome of a growing population of young and elderly MM patients.

How to Treat High-Risk Myeloma at Diagnosis and Relapse

Survival in multiple myeloma has improved greatly during the past 2 decades, but this change has primarily benefited patients who have standard-risk disease. Patients with high-risk disease remain a challenge to diagnose and treat. To improve their clinical outcomes, it is imperative to develop tools to readily identify them and to provide them with the most effective available treatments. The most widely used stratification system, the revised International Staging System, incorporates serum β-2 microglobulin, albumin, lactate dehydrogenase, and high-risk chromosomal abnormalities [del(17p), t(4;14), and t(14;16)]. Recent updates have included mutational status and chromosome 1q abnormalities. Plasma cell leukemia, extramedullary disease, circulating plasma cells, renal failure, and frailty are also associated with poor outcome. The treatment approach for a newly diagnosed patient with high-risk multiple myeloma should include induction therapy, autologous stem cell transplantation if appropriate, and maintenance therapy. Triplet therapy with a proteasome inhibitor, immunomodulatory drug, and steroid, with or without an anti-CD38 antibody, should be considered for induction, along with a proteasome inhibitor and/or immunomodulatory drug for maintenance. Aiming for a deep and sustained response is important. Similar principles apply at relapse, with close monitoring of response, especially extramedullary disease and active management of side effects, so that patients can continue therapy and benefit from treatment. Immune-based therapies, including autologous CAR T-cell-based therapies and bispecific antibodies, show promising activity in relapsed disease and are being actively explored in earlier disease settings. As the prognosis for high-risk disease remains poor, the future goal for this patient group is to develop specific clinical trials to explore novel approaches and therapies efficiently.

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.

Improved survival in multiple Myeloma patients undergoing autologous stem cell transplantation is entirely in the standard cytogenetic risk groups

INTRODUCTION

Novel drugs and drug combinations have improved outcomes for multiple myeloma patients. However, subgroups of patients still have a poor progression-free survival (PFS) and overall survival (OS). In an attempt to identify how the novel drugs affect the outcome in standard-risk and high-risk patients, respectively, we have investigated 715 multiple myeloma (MM) patients who have undergone high dose treatment followed by autologous stem cell transplantation at our center during 1995 - 2020. Outcomes during three time periods, 1995-1999 (period I), 2000-2009 (period II), and 2010-2020 (period III), were compared separately for standard-risk and high-risk patients. Risk stratification was based on chromosome analysis for periods II and III.

RESULTS

The whole cohort of patients showed significantly improved OS with time during the three periods being at a median of 5.8, 7.0, and 10.0 years, respectively. There is also a weak tendency for improved PFS, that is, a median of 2.4, 2.6, and 2.9 years, respectively, during the same periods. However, the separate analysis of standard-risk and high-risk patients showed that the overall improvement with time was due to improved standard-risk patients (median OS 8.4 years for the period I and not reached for period II and III). In contrast, no significant improvement was seen in high-risk patients. For patients with del17p, PFS was even worse during period III as compared to period II (median 1.6 vs 3.2 years respectively).

CONCLUSION

Our results show that the dramatic improvement in outcome for MM patients during the last 20 years only applies for standard-risk patients, while high-risk MM patients still are doing poorly, indicating that the novel drugs developed during this time are preferentially effective in standard-risk patients. New treatment modalities like CAR-T cells, CAR-NK cells, and/or bispecific antibodies should be tried in clinical studies early in the course of the disease, especially in patients with high-risk cytogenetics.

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.

Upfront stem cell transplantation for newly diagnosed multiple myeloma with del(17p) and t(4;14): a study from the CMWP-EBMT

We analyzed newly diagnosed multiple myeloma patients with del(17p) and/or t(4;14) undergoing either upfront single autologous (auto), tandem autologous (auto-auto) or tandem autologous/reduced-intensity allogeneic (auto-allo) stem cell transplantation. 623 patients underwent either auto (n = 446), auto-auto (n = 105), or auto-allo (n = 72) between 2000 and 2015. 46% of patients had t(4;14), 45% had del(17p) while 9% were reported having both abnormalities. Five-year overall survival (OS) was 51% (95% confidence interval [CI], 45-58%) for single auto, 60% (95% CI, 49-72%) for auto-auto, and 67% (95% CI, 53-80%) for auto-allo (p = 0.187). Five-year progression-free survival (PFS) was 17% (95% CI, 12-22%), 33% (95% CI, 22-43%), and 34% (95% CI, 21-38%; p = 0.048). Five-year relapse rate was 82, 63, and 56%, while non-relapse mortality was 1, 4, and 10%. In multivariable analysis, in t(4;14) with single auto as reference, auto-auto (hazard ratio [HR], 0.44; p = 0.007) and auto-allo (HR, 0.45; p = 0.018) were associated with better PFS. In terms of t(4;14) and OS, auto-auto appeared to improve outcome compared with single auto (HR, 0.49; p = 0.096). In del(17p), outcome in PFS was similar between single auto and auto-auto, while auto-allo appeared to improve PFS (HR, 0.65; p = 0.097). No significant difference in OS was identified between the groups in patients with del(17p).

Allogeneic Transplantation in Multiple Myeloma-Does It Still Have a Place?

Novel drugs have improved survival for patients with multiple myeloma in recent years. However, the disease is still fatal. Allogeneic stem cell transplantation (Allo) has proven to cure some patients with the disease, but its role is controversial due to relatively high transplant-related toxicity and mortality (nonrelapse mortality, NRM). Using nonmyeloablative reduced-intensity conditioning (RIC), both toxicity and NRM can be reduced, and RICAllo is, therefore, an option for subgroups of patients. Upfront tandem autologous/RICAllo (Auto/RICAllo) was shown to be superior to single Auto or tandem Auto/Auto in both progression-free (PFS) and overall survival (OS) in two prospective studies with long-term follow-up, while three similarly designed studies did not detect a difference. A recent update of pooled patient data from four of these studies showed significantly superior PFS and OS with Auto/RICAllo. Importantly, none of these studies showed inferior results with Auto/RICAllo in patients less than 70 years of age. Auto/RICAllo appears to overcome some poor risk cytogenetic markers. Encouraging results have also been seen in treatment of relapsed patients. Combining Allo with new proteasome inhibitors and immunomodulatory drugs may further improve results. Other encouraging new cell therapies such as with CAR T-cells, NK- and CAR NK-cells may well have a place in combination with RICAllo. Such studies are warranted.

Bispecific Antibodies: A New Era of Treatment for Multiple Myeloma

Despite the introduction of novel agents such as proteasome inhibitors, immunomodulatory drugs, and autologous stem cell transplant, multiple myeloma (MM) largely remains an incurable disease. In recent years, monoclonal antibody-based treatment strategies have been developed to target specific surface antigens on MM cells. Treatment with bispecific antibodies (bsAbs) is an immunotherapeutic strategy that leads to an enhanced interaction between MM cells and immune effector cells, e.g., T-cells and natural killer cells. With the immune synapse built by bsAbs, the elimination of MM cells can be facilitated. To date, bsAbs have demonstrated encouraging results in preclinical studies, and clinical trials evaluating bsAbs in patients with MM are ongoing. Early clinical data show the promising efficacy of bsAbs in relapsed/refractory MM. Together with chimeric antigen receptor-modified (CAR)-T-cells, bsAbs represent a new dimension of precision medicine. In this review, we provide an overview of rationale, current clinical development, resistance mechanisms, and future directions of bsAbs in MM.

Long-Term Follow-up of CALGB (Alliance) 100001: Autologous Followed by Nonmyeloablative Allogeneic Transplant for Multiple Myeloma

CALGB (Alliance) 100001 was a phase II study evaluating autologous stem cell transplant (ASCT) followed by nonmyeloablative allogeneic stem cell transplant (alloSCT) in patients with multiple myeloma who had received no more than 18 months of prior therapy and had experienced no more than 1 prior progression event. Conditioning for ASCT was with high-dose melphalan (200 mg/m²). The alloSCT reduced-intensity conditioning (RIC) regimen consisted of fludarabine (30 mg/m²/d i.v. on days -7 through -3) and cyclophosphamide (1 g/m²/d i.v. on days -4 through -3). The primary objective was to determine the 6-month post-alloSCT treatment-related mortality (TRM) rate. Additional objectives included determining the proportion of patients who could complete this tandem ASCT-alloSCT approach in a cooperative group setting, overall response rates, rates of donor chimerism, rates of graft-versus-host disease (GVHD), disease-free survival, and overall survival (OS). Sixty patients were enrolled, of whom 57 (95%) completed ASCT and 49 (82%) completed tandem ASCT-alloSCT. The TRM rate was 2% (1/49; 90% confidence interval, 0.10% to 9.3%). Moderate to severe (grades 2 to 3) acute GVHD was observed in 13 of 49 alloSCT patients (27%). One patient died due to GVHD within 9 months of alloSCT. Twenty-seven of the 49 patients (55%) who underwent alloSCT reported chronic GVHD as either limited (15/49; 31%) or extensive (12/49; 24%) in the first year post-alloSCT and prior to the start of nonprotocol therapy for progressive disease. With a median follow-up for survival of 11 years, the median OS time is 6.6 years and the median time to disease progression is 3.6 years. Similar to other studies, this study confirmed that tandem ASCT/alloSCT is associated with durable disease control in a subset of patients. This study demonstrated the feasibility of performing tandem ASCT/alloSCT in a cooperative group setting and determined that a fludarabine/cyclophosphamide RIC regimen is associated with a very low TRM rate.

Summary of the Third Annual Blood and Marrow Transplant Clinical Trials Network Myeloma Intergroup Workshop on Minimal Residual Disease and Immune Profiling

The third annual Blood and Marrow Transplant Clinical Trials Network (BMT CTN) Myeloma Intergroup Workshop on Minimal Residual Disease and Immune Profiling was held on November 29, 2018, at the American Society of Hematology (ASH) annual meeting. This workshop featured the latest research focused on minimal residual disease (MRD) assessment and immune profiling (IP) in myeloma as well as discussion of the statistical and regulatory issues intrinsic to the development of MRD as a surrogate endpoint. In this report, we provide a summary of the workshop and focus on the integration of MRD and IP assessment into trial design and clinical practice.