Autotransplant with and without induction chemotherapy in older multiple myeloma patients: long-term outcome of a randomized trial

Functional cure and long-term survival in multiple myeloma: how to challenge the previously impossible

Multiple myeloma (MM) is a heterogeneous disease with survival ranging from months to decades. The goal of 'cure' remains elusive for most patients, but has been shown to be possible, with durable remission and a transition to a plateau phase (analogous to monoclonal gammopathy of uncertain significance/smoldering myeloma). In this review, two representative cases set the stage to illustrate how this might be possible and what still needs to be determined to achieve functional disease control over a prolonged period. Several developments have emerged, such as improved diagnostics including the definitions and use of SLiM-CRAB criteria and measurable residual disease (MRD) with whole-genome/single-cell sequencing as well as other correlates to better understand disease biology. These advances enable earlier detection, more accurate risk stratification and improved personalized treatment strategies by facilitating analysis of genetic alterations and clonal heterogeneity. Whole-genome sequencing may also identify driver mutations and modes of resistance to immunotherapies as well as other targeted therapies. Today, induction with a CD38 antibody, proteasome inhibitor, immunomodulatory drug, and dexamethasone, potentially followed by autologous stem cell transplantation and lenalidomide maintenance, can be considered standard of care for transplant-eligible (TE) patients with newly diagnosed MM (NDMM). That prolonged disease control and functional cure can be achieved in non-transplant-eligible (NTE) patients is currently emerging as a distinct possibility: data from phase III trials that incorporate a CD38 antibody into the treatment of NTE NDMM patients demonstrate impressive MRD negativity rates that appear sustained over several years. While the long-term durability of chimeric antigen receptor T cells, bi-specific antibodies and other immunotherapies are being evaluated, several clinical trials are now investigating their role in frontline treatment for TE and NTE patients. These trials will address whether chimeric antigen receptor T-cell therapy will replace autologous stem cell transplantation and whether such immunotherapies will represent a truly curative option. We conclude that while cure remains elusive, the concept of operational or functional cure provides a new benchmark to strive for and is an emerging area of active and potentially achievable clinical research for MM.

Autologous stem cell transplantation in patients older than 65 years with multiple myeloma: a real-world study

INTRODUCTION

The treatment of elderly multiple myeloma (MM) patients with autologous stem cell transplantation (ASCT) is a controversial procedure. Most clinical trials evaluating the safety and efficacy of ASCT have primarily included patients younger than 65 years.

DESIGN AND METHODS

This was a retrospective analysis of patients with MM who underwent ASCT between 2008 and 2018. Patients at or over 65 years were compared with patients under 65 years. We analyzed treatment-related mortality (TRM), response rate, progression-free survival (PFS) and overall survival (OS).

RESULTS

Two hundred and twenty-one patients were included: 50 patients at or over 65 years, (median age 68 years), including 7 patients over 70 years and 151 patients under 65 years, (median age 57 years). No differences were found in the neutrophil and platelet engraftment, median days of hospitalization and life support requirement during the hospitalization period for the ASCT. No statistically significant differences were found in the incidence of TRM between both groups at 100 days post-transplant (2% vs. 2.9%, p = 0.322). The ASCT improved complete response and stringent complete response rates (44% vs. 37%, p < 0.001). Survival was not modified by age: after a median follow-up of 53 months, the estimated PFS rates at three years were 63% and 60% (p = 0.88) and the OS rates at five years were 75% and 74% (p = 0.72), respectively.

CONCLUSIONS

Our data suggest that the ASCT is feasible in selected elderly patients with MM over 65 years of age, achieving response and survival rates similar to those of younger patients.

The limited use of autologous hematopoietic stem cell transplant for fit older patients with multiple myeloma in India: a retrospective analysis

Background

Multiple myeloma (MM) predominantly affects older patients; many of whom do not undergo autologous hematopoietic stem cell transplant (AHSCT) despite the associated survival benefits. This study was conceived to investigate the patterns of AHSCT among MM patients with due regard to their age and standardized fitness assessments.

Methods

Fitness scores as per the hematopoietic stem cell transplant-comorbidity index (HSCT-CI) and risk scores as per the revised-myeloma comorbidity index (R-MCI) of MM patients treated between January 2017 and December 2019 were analyzed to assess fitness for AHSCT. Proportions of patients who underwent AHSCT were calculated with regard to age and fitness for AHSCT.

Results

Of the 81 eligible patient records with a median age of 62 years, the HSCT-CI classified 79.6% and 77.8% of patients aged ≤65 years and >65 years as AHSCT eligible (p 1). Using the R-MCI, 96.3% and 81.5% of patients aged ≤65 years and >65 years, respectively, were classified as eligible for AHSCT (p 0.0381). Overall, patients aged ≤65 years underwent AHSCT with a greater frequency compared to those aged >65years (38.9 vs. 14.8%, p 0.0402). Irrespective of the age group, there was a statistically significant difference (p 0.0167) in terms of survival which favored those who underwent AHSCT.

Conclusions

Both the HSCT-CI and the R-MCI revealed that nearly 80% of patients aged >65 years were fit enough to receive AHSCT. However, far fewer patients of this age group underwent AHSCT. We propose that the routine inclusion of objective fitness assessment could ensure that fit older patients undergo AHSCT and thus do not miss out on the benefits of the same.

Managing multiple myeloma in a resource-limited region: Diagnosis and treatment in Armenia

Multiple myeloma (MM) is the second most common blood cancer in adults leading to 117,000 deaths every year. Major breakthroughs in clinical research of the past decades transformed the diagnosis and treatment of MM improving the survival rates and overall quality of life of patients. Unfortunately, scientific advancements are not distributed equally around the globe leading to disparities in the treatment outcomes between different regions of the world. Management of MM in low- and middle-income countries represents a big challenge for healthcare providers considering the economic, technological, and infrastructural restraints in comparison to developed countries. Many standards of practice, including diagnostic tools and therapeutic regimens, are not available in developing regions of the world. As an example of an upper-middle-income country, Armenia has been witnessing considerable progress in the diagnosis and treatment of MM, including but not limited to the establishment of autologous stem cell transplant (ASCT), accessibility to modern anti-myeloma medications, and improved diagnostic and monitoring workup. Despite significant improvements, there is still a need for refinement in the management of MM. The aim of this review article is to discuss the latest developments and the current diagnosis and treatment of MM in Armenia as an example of a resource-limited region.

Full or intensity-reduced high-dose melphalan and single or double autologous stem cell transplant with or without bortezomib consolidation in patients with newly diagnosed multiple myeloma

OBJECTIVE

A post hoc subgroup analysis of two phase III trials (NCT00416273, NCT00416208) was carried out to investigate the influence of 100/140 and 200 mg/m² melphalan as well as single/double autologous stem cell transplantation (ASCT) on progression-free survival (PFS). Additionally, the effect of bortezomib consolidation on PFS was analyzed.

METHODS

Following induction therapy and high-dose melphalan with subsequent ASCT, patients with newly diagnosed multiple myeloma (NDMM) were randomized 1:1 to either four 35-day cycles of bortezomib consolidation (1.6 mg/m² IV on days 1, 8, 15, 22) or observation.

RESULTS

Of the 340 patients included in this analysis, 13.5% received 1 × MEL100/140, 22.9% 2 × MEL100/140, 31.2% 1 × MEL200, and 32.4% 2 × MEL200. With higher cumulative melphalan dose, PFS improved (P = .0085). PFS curves of patients treated with 2 × MEL100/140 and 1 × MEL200 were very similar. The superior dose effect of MEL200 over MEL100/140 was non-existent in the bortezomib consolidation arm but pronounced in the observation arm (P = .0015). Similarly, double ASCT was only beneficial in patients without bortezomib consolidation (P = .0569).

CONCLUSIONS

Full dose melphalan and double transplantation seem advantageous only as long as patients are not receiving bortezomib consolidation afterwards.

Decisional involvement and information preferences of patients with hematologic malignancies

Understanding decisional involvement and information preferences in patients with hematologic malignancies may help to optimize physician-patient communication about treatment decisions and align the decision-making processes with patients' preferences. We described and examined factors associated with preferences of patients with hematologic malignancies for decisional involvement, information sources, and presentation of information. In a multicenter observational study, we recruited 216 patients with hematologic malignancies of any stage from September 2003 to June 2007. Patients were asked about their decisional involvement preferences (Control Preferences Scale), information sources (including most useful source of information), and preferences for their oncologists' presentation of treatment success information. We used multivariate logistic regressions to identify factors associated with decisional involvement preferences and usefulness of information sources (physicians vs nonphysicians). Patient-directed, shared, and physician-directed approaches were preferred in 34%, 38%, and 28% of patients, respectively. Physicians and computer/Internet were the most common information sources; 42% perceived physicians as the most useful source. On multivariate analysis, patients with less than a college education (vs postgraduate education) were less likely to perceive their physician as the most useful source (adjusted odds ratio [AOR], 0.46; 95% confidence interval (CI), 0.21-1.00), whereas patients with acute leukemia (vs other blood cancers) were more likely to perceive their physician as the most useful source (AOR, 2.49; 95% CI, 1.07-5.80). In terms of communicating treatment success rates, 70% preferred ≥1 method(s), and 88% preferred presentation in percentages. Our study suggests that decisional involvement and information preferences vary and should be assessed explicitly as part of each decision-making encounter.

Bortezomib-based induction, high-dose melphalan and lenalidomide maintenance in myeloma up to 70 years of age

Intensive upfront therapy in newly-diagnosed multiple myeloma (MM) including induction therapy (IT), high-dose melphalan (MEL200), and autologous blood stem cell transplantation (ASCT) followed by consolidation and/or maintenance is mostly restricted to patients up to 65 years of age. Prospective phase III trial data in the era of novel agents for patients up to 70 years of age are not available. The GMMG-MM5 trial included 601 patients between 18 and 70 years of age, divided in three groups for the present analysis: ≤60 years (S1, n = 353), 61–65 years (S2, n = 107) and 66–70 years (S3, n = 141). Treatment consisted of a bortezomib-containing IT, MEL200/ASCT, consolidation, and maintenance with lenalidomide. Adherence to treatment was similar among patients of the three age groups. Overall toxicity during all treatment phases was increased in S2 and S3 compared to S1 (any adverse event/any serious adverse event: S1:81.7/41.8% vs. S2:90.7/56.5% vs. S3:87.2/68.1%, p = 0.05/<0.001). With respect to progression-free survival (log-rank p = 0.73), overall survival (log-rank p = 0.54) as well as time-to-progression (Gray’s p = 0.83) and non-relapse mortality (Gray’s p = 0.25), no differences were found between the three age groups. Our results imply that an intensive upfront therapy with a bortezomib-containing IT, MEL200/ASCT, lenalidomide consolidation, and maintenance should be applied to transplant-eligible MM patients up to 70 years of age.

Multiple myeloma: Role of autologous transplantation

Autologous stem cell transplantation (ASCT) has been the mainstay of multiple myeloma (MM) treatment for approximately 30 years. Although the continuous introduction of novel agents in the armamentarium against MM has questioned its value, ASCT remains a backbone treatment for fit MM patients. However, there is no unanimous approach for several aspects including the positioning of ASCT in the therapeutic algorithm either upfront or following the first relapse, the need for single or tandem ASCT, as well as the role of ASCT as salvage therapy. Furthermore, the anti-CD38 monoclonal antibodies along with the next generation proteasome inhibitors and immunomodulatory drugs provide a platform for optimizing the induction and consolidation/maintenance regimens. In this review, we present current data pertaining to all aspects of ASCT in MM, whereas we highlight the open issues that should be addressed in the design of future clinical trials in the field.

Special considerations for the treatment of multiple myeloma according to advanced age, comorbidities, frailty and organ dysfunction

Multiple Myeloma (MM) is primarily a disease of old age with a median age of sixty-nine years at diagnosis. The development of novel therapies for induction and use of autologous stem cell transplantation has resulted in improved clinical outcomes and better quality of life for MM patients. Elderly patients, comprising the majority of MM population, have a higher incidence of age-related comorbidities, frailty and organ dysfunction which complicates the coordination of treatment and limits the selection of therapies. Even in the era of multiple chemotherapeutic options, the clinical heterogeneity of the myeloma patients' demands personalized treatments which often require dose-adjustments or dose delays. The use of reduced-dose regimens and various comorbidity indices has improved clinical outcome and regimen tolerability in MM patients with renal, neurological and bone abnormalities. We focus on advancements in the treatment of multiple myeloma with the goal to guide clinicians towards patient-specific management.

Is there still a role for stem cell transplantation in multiple myeloma?

High-dose chemotherapy and autologous stem cell transplantation (ASCT) are a standard of care for transplant-eligible patients with newly diagnosed multiple myeloma (MM). The introduction of novel agents, which range from immunomodulatory drugs and proteasome inhibitors to monoclonal antibodies and have now been integrated into both induction and salvage regimens, has dramatically revolutionized the treatment landscape of MM and challenged the role of high-dose chemotherapy and ASCT in treating MM. These advances have led to a number of provocative questions. First, what is the current role of stem cell transplantation (SCT) in comparison with standard-dose therapy incorporating novel agents? Second, should ASCT be performed upfront ("early") or later ("delayed") in the course of the disease? Third, should single or double ASCT be performed? Fourth, is allogeneic SCT still an option for patients with MM? This article provides an overview of available data and evidence-based responses regarding the role of SCT in MM.

Current status of autologous stem cell transplantation for multiple myeloma

More than 30 years after its introduction, autologous stem cell transplantation (ASCT) remains the standard of care for young patients with newly diagnosed multiple myeloma. Not only did the arrival of novel agents such as immunomodulatory drugs (IMiDs), proteasome inhibitors (PI) and monoclonal antibodies not replace ASCT, instead they solidified its central role as standard of care. Novel agent use is now inarguably essential in induction, maintenance, and possibly consolidation. In light of these new advancements, new challenges arise in deciding on optimal practice. Who is most suited to undergo ASCT? Is there an age threshold that should not be surpassed? Should transplantation be embarked on early or is it reasonable to delay it? What are the optimal induction, consolidation, and maintenance therapies? What is the role of tandem transplantation in the era of novel agents and where do patient-specific cytogenetics come into the equation when deciding on treatment? These are some of the questions addressed in this review which we will attempt to answer with the latest currently available data.

Treatment of Multiple Myeloma: ASCO and CCO Joint Clinical Practice Guideline

PURPOSE

To provide evidence-based recommendations on the treatment of multiple myeloma to practicing physicians and others.

METHODS

ASCO and Cancer Care Ontario convened an Expert Panel of medical oncology, surgery, radiation oncology, and advocacy experts to conduct a literature search, which included systematic reviews, meta-analyses, randomized controlled trials, and some phase II studies published from 2005 through 2018. Outcomes of interest included survival, progression-free survival, response rate, and quality of life. Expert Panel members used available evidence and informal consensus to develop evidence-based guideline recommendations.

RESULTS

The literature search identified 124 relevant studies to inform the evidence base for this guideline.

RECOMMENDATIONS

Evidence-based recommendations were developed for patients with multiple myeloma who are transplantation eligible and those who are ineligible and for patients with relapsed or refractory disease.

Approach to the Older Adult With Multiple Myeloma

Multiple myeloma (MM) is a disease of aging adults, and numerous therapeutic options are available for this growing demographic. MM treatment of older adults continues to evolve and includes novel combinations, new generations of targeted agents, immunotherapy, and increasing use of autologous stem cell transplantation (ASCT). Understanding age-related factors, independent of chronologic age itself, is an increasingly recognized factor in MM survivorship, especially in understudied populations, such as octogenarians. Octogenarians have inferior survival that cannot be explained by cytogenetic profiles alone. Incorporating assessments of geriatric factors can provide guidance on how to intensify or de-escalate therapeutic options. Functional status, using objective testing, is superior to traditional metrics of performance status and should be implemented to optimize the risk-benefit ratio of ASCT. ASCT is feasible and cost-effective, and chronologic age should not exclude ASCT eligibility. Upfront ASCT remains the standard of care, in the context of a sequential approach that includes pre-transplantation induction and post-transplantation maintenance. High-risk MM is classically defined by disease characteristics, yet shifting frameworks suggest that the high-risk designation could refer to any patient subgroup who is at risk for poorer outcomes-beyond disease-focused outcomes to patient-focused outcomes. Defining the optimal treatment of subgroups of older patients with high-risk disease on the basis of chromosomal abnormalities is unexplored. Here, we review tools to assess individual health status, explore vulnerability in octogenarians with MM, address ASCT decision-making, and examine high-risk MM to understand factors that contribute to survival disparities for older adults with MM.

How I treat elderly patients with plasma cell dyscrasias

Plasma cell dyscrasias are a rare heterogeneous group of hematological disorders which are more prevalent in the older part of the population. The introduction of novel agents, improved understanding of disease biology and better supportive management have improved outcomes considerably and in the era of the aging population the question of how to best manage older patients with plasma cell dyscrasias has never been more relevant. Data on how to treat these patients comes mostly from subgroup analysis as they are underrepresented in clinical trials. This review will cover issues, available evidence and recommendations relevant to diagnosis and management of the older patients with Multiple Myeloma (MM), Waldenstrom Macroglobulinemia (WM) and systemic AL Amyloidosis. What will become increasingly evident is the need to develop and establish the use of disease-specific geriatric assessment (GA) tools. Frailty status assessment using GA tools and moving away from making decisions based merely on chronological age will allow setting clear treatment goals and consequently achieving an optimum balance between effectiveness and toxicity for this complex and heterogeneous group of patients.

Real-life data on safety and efficacy of autologous stem cell transplantation in elderly patients with multiple myeloma

Autologous stem cell transplantation (ASCT) is still debatable in treatment of patients over 65 years with multiple myeloma (MM). We performed a retrospective analysis of newly diagnosed MM patients who underwent ASCT between January 2010 and July 2016. A non-transplanted group with similar clinical characteristics, aged 65-70 years old, diagnosed and treated in the same timeline was used for comparison. We analyzed a total of 155 patients, 132 of which underwent ASCT (≤ 65 years, n = 103, median 56 years; > 65 years, n = 29, median 67 years) and 23 non-transplanted (median 68 years). Conditioning consisted of melphalan 200 mg/m² (MEL200) in younger patients and melphalan 140 mg/m² (MEL140) in half of elderly patients. Stratifying by age, there were no statistically significant differences concerning transplant-related myelotoxicity and non-hematopoietic toxicity; however, elderly patients conditioned with MEL200 had higher needs of transfusional support and more days of intravenous antibiotics. Those patients also had higher needs of transfusional support, higher grade of mucositis (p = 0.028), and more days of intravenous antibiotics (p = 0.019) than the elderly transplanted with MEL140. Global transplant-related mortality was 3.8%. Survival was not influenced by age. Non-transplanted elderly patients had comparable disease features, and induction response was similar in both groups (before ASCT in the transplanted cohort). Survival of transplanted elderly patients was superior to non-transplanted (OS, 59 months vs 30 months, p = 0.037; EFS, 45 months vs 27 months, p = 0.014). Selected elderly patients when transplanted have similar disease response and survival as younger patients. A higher dose of melphalan has more toxicity, but it is globally a well-tolerated procedure.

Frontline treatment for transplant-eligible multiple myeloma: A 6474 patients network meta-analysis

Autologous transplantation continues to be the cornerstone of younger and fit multiple myeloma patients. It is known that frontline induction therapy before transplantation can influence post-transplant results. Therefore, best frontline treatment for transplant-eligible patients should be based on best available evidence to guide therapy. Furthermore, until now due to data scarcity, it was not possible to thoroughly compare lenalidomide to other regimens in this setting. We performed a systematic review and network (mixed treatment comparison) meta-analysis of 21 clinical trial publications, enrolling 6474 patients and comparing 11 different treatment frontline setting regimens regarding survival, response, and safety outcomes. OS analysis showed superiority of CRD (cyclophosphamide-lenalidomide-dexamethasone) over TD-based (thalidomide-dexamethasone, HR = 0.76,0.62-0.90), VAD-based (HR = 0.71,0.52-0.90), and Z-Dex (idarubicin-dexamethasone, HR = 0.37,0.17-0.76) regimens. Concerning PFS, VTD (bortezomib-thalidomide-dexametasone) showed superior results when compared with TD-based (HR = 0.66,0.51-0.84), VAD-based (HR = 0.61,0.46-0.82), Z-Dex (HR = 0.42,0.22-0.78), and high dose dexamethasone (Dex, HR = 0.62,0.41-0.90) regimens. Bortezomib/thalidomide regimens were not superior to lenalidomide, considering these outcomes. Also, concerning complete and overall response, VTD ranked first among other regimens, showing clear superiority over thalidomide-only containing protocols. Safety outcome evaluated infectious, cardiac, gastrointestinal, neurological, thrombotic, and hematological grade 3 to 4 adverse events. Risk of thrombotic events was higher with TAD (thalidomide-doxorubicin-dexamethasone), neurological with PAD (bortezomib-doxorubicin-dexamethasone), infectious with Dex, hematological with Z-Dex, gastrointestinal with VTD, and cardiac with PAD regimens. Our study endorses current recommendations on combined immunomodulatory drugs and proteasome inhibitors frontline regimens (in triplets) in transplant-eligible multiple myeloma patients, but also formally demonstrates the favorable performance of lenalidomide in overall and progression-free survival, when compared with bortezomib/thalidomide protocols.

Novel Treatments for Multiple Myeloma: What Role Do They Have in Older Adults?

Multiple myeloma is a malignant plasma cell disease, which typically affects older patients, with a median age at diagnosis of 70 years. The recent introduction of novel drugs and ongoing improvements in supportive care have significantly contributed to overall better management and outcomes for patients with multiple myeloma. Autologous stem-cell transplantation has been a standard part of therapy for myeloma patients for many years, first in younger patients and increasingly in older, and may still be considered in selected older patients with myeloma. In addition, in both newly diagnosed patients and in the relapsed/refractory setting, a number of novel agents tested in large phase III trials have yielded improvements in overall outcomes. As clinical trials under-enrol older patients and have stringent exclusion criteria, the data and results from them may not be generalizable to all older adults. In this review, we examine the treatment options for older adults with myeloma with a specific focus on the currently available data on novel agents in this cohort. The clinical efficacy and unique toxicity profile of each novel agent must be considered prior to the treatment plan in older adults.

From transplant to novel cellular therapies in multiple myeloma: European Myeloma Network guidelines and future perspectives

Survival of myeloma patients has greatly improved with the use of autologous stem cell transplantation and novel agents, such as proteasome inhibitors, immunomodulatory drugs and monoclonal antibodies. Compared to bortezomib- and lenalidomide-based regimens alone, the addition of high-dose melphalan followed by autologous transplantation significantly improves progression-free survival, although an overall survival benefit was not observed in all trials. Moreover, follow up of recent trials is still too short to show any difference in survival. In the light of these findings, novel agent-based induction followed by autologous transplantation is considered the standard upfront treatment for eligible patients (level of evidence: 1A). Post-transplant consolidation and maintenance treatment can further improve patient outcome (1A). The availability of several novel agents has led to the development of multiple combination regimens such as salvage treatment options. In this context, the role of salvage autologous transplantation and allotransplant has not been extensively evaluated. In the case of prolonged remission after upfront autologous transplantation, another autologous transplantation at relapse can be considered (2B). Patients who experience early relapse and/or have high-risk features have a poor prognosis and may be considered as candidates for clinical trials that, in young and fit patients, may also include an allograft in combination with novel agents (2B). Ongoing studies are evaluating the role of novel cellular therapies, such as inclusion of antibody-based triplets and quadruplets, and chimeric antigen receptor-T cells. Despite encouraging preliminary results, longer follow up and larger patient numbers are needed before the clinical use of these novel therapies can be widely recommended.

Melphalan 140 mg/m2 or 200 mg/m2 for autologous transplantation in myeloma: results from the Collaboration to Collect Autologous Transplant Outcomes in Lymphoma and Myeloma (CALM) study. A report by the EBMT Chronic Malignancies Working Party

Melphalan at a dose of 200 mg/m² is standard conditioning prior to autologous hematopoietic stem cell transplantation for multiple myeloma, but a dose of 140 mg/m² is often used in clinical practice in patients perceived to be at risk of excess toxicity. To determine whether melphalan 200 mg/m² and melphalan 140 mg/m² are equally effective and tolerable in clinically relevant patient subgroups we analyzed 1964 first single autologous transplantation episodes using a series of Cox proportional-hazards models. Overall survival, progression-free survival, cumulative incidence of relapse, non-relapse mortality, hematopoietic recovery and second primary malignancy rates were not significantly different between the melphalan 140 mg/m² (n=245) and melphalan 200 mg/m² (n=1719) groups. Multivariable subgroup analysis showed that disease status at transplantation interacted with overall survival, progression-free survival, and cumulative incidence of relapse, with a significant advantage associated with melphalan 200 mg/m² in patients transplanted in less than partial response (adjusted hazard ratios for melphalan 200 mg/m²versus melphalan 140 mg/m²: 0.5, 0.54, and 0.56). In contrast, transplantation in very good partial or complete response significantly favored melphalan 140 mg/m² for overall survival (adjusted hazard ratio: 2.02). Age, renal function, prior proteasome inhibitor treatment, gender, or Karnofsky score did not interact with overall/progression-free survival or relapse rate in the melphalan dose groups. There were no significant survival or relapse rate differences between melphalan 200 mg/m² and melphalan 140 mg/m² patients with high-risk or standard-risk chromosomal abnormalities. In conclusion, remission status at the time of transplantation may favor the use of melphalan 200 mg/m² or melphalan 140 mg/m² for key transplant outcomes (NCT01362972).