Importance of achieving stringent complete response after autologous stem-cell transplantation in multiple myeloma

Prognostic factors in 448 newly diagnosed multiple myeloma receiving bortezomib-based induction: impact of ASCT, transplant refusal and high-risk MM

In Hong Kong, newly diagnosed multiple myeloma (NDMM) receives bortezomib-based triplet induction. Upfront autologous stem cell transplant (ASCT) is offered to transplant eligible (TE) patients (NDMM ≤ 65 years of age), unless medically unfit (TE-unfit) or refused (TE-refused). Data was retrieved for 448 patients to assess outcomes. For the entire cohort, multivariate analysis showed that male gender (p = 0.006), international staging system (ISS) 3 (p = 0.003), high lactate dehydrogenase (LDH) (p = 7.6 × 10-7) were adverse predictors for overall survival (OS), while complete response/ near complete response (CR/nCR) post-induction (p = 2.7 × 10-5) and ASCT (p = 4.8 × 10-4) were favorable factors for OS. In TE group, upfront ASCT was conducted in 252 (76.1%). Failure to undergo ASCT in TE patients rendered an inferior OS (TE-unfit p = 1.06 × 10-8, TE-refused p = 0.002) and event free survival (EFS) (TE-unfit p = 0.00013, TE-refused p = 0.002). Among TE patients with ASCT, multivariate analysis showed that age ≥ 60 (p = 8.9 × 10-4), ISS 3 (p = 0.019) and high LDH (p = 2.6 × 10-4) were adverse factors for OS. In those with high-risk features (HR cytogenetics, ISS 3, R-ISS 3), ASCT appeared to mitigate their adverse impact. Our data reaffirmed the importance of ASCT. The poor survival inherent with refusal of ASCT should be recognized by clinicians. Finally, improved outcome with ASCT in those with high-risk features warrant further studies.

Progression free survival of myeloma patients who become IFE-negative correlates with the detection of residual monoclonal free light chain (FLC) by mass spectrometry

Deeper responses are associated with improved survival in patients being treated for myeloma. However, the sensitivity of the current blood-based assays is limited. Historical studies suggested that normalisation of the serum free light chain (FLC) ratio in patients who were negative by immunofixation electrophoresis (IFE) was associated with improved outcomes. However, recently this has been called into question. Mass spectrometry (MS)-based FLC assessments may offer a superior methodology for the detection of monoclonal FLC due to greater sensitivity. To test this hypothesis, all available samples from patients who were IFE negative after treatment with carfilzomib and lenalidomide-based induction and autologous stem cell transplantation (ASCT) in the Myeloma XI trial underwent FLC-MS testing. FLC-MS response assessments from post-induction, day+100 post-ASCT and six months post-maintenance randomisation were compared to serum FLC assay results. Almost 40% of patients had discordant results and 28.7% of patients with a normal FLC ratio had residual monoclonal FLC detectable by FLC-MS. FLC-MS positivity was associated with reduced progression-free survival (PFS) but an abnormal FLC ratio was not. This study demonstrates that FLC-MS provides a superior methodology for the detection of residual monoclonal FLC with FLC-MS positivity identifying IFE-negative patients who are at higher risk of early progression.

Performance Characteristics and Limitations of the Available Assays for the Detection and Quantitation of Monoclonal Free Light Chains and New Emerging Methodologies

Light chain measurements form an essential component of the testing strategy for the detection and monitoring of patients with suspected and/or proven plasma cell disorders. Urine-based electrophoretic assays remain at the centre of the international guidelines for response assessment but the supplementary role of serum-free light chain (FLC) assays in response assessment and the detection of disease progression due to their increased sensitivity has been increasingly recognised since their introduction in 2001. Serum FLC assays have also been shown to be prognostic across the spectrum of plasma cell disorders and are now incorporated into risk stratification scores for patients with monoclonal gammopathy of undetermined significance (MGUS), smouldering multiple myeloma, and light chain amyloidosis (AL amyloidosis), as well as being incorporated into the criteria for defining symptomatic multiple myeloma. There are now multiple different commercially available serum FLC assays available with differing performance characteristics, which are discussed in this review, along with the implications of these for patient monitoring. Finally, newer methodologies for the identification and characterisation of monoclonal FLC, including modifications to electrophoretic techniques, mass spectrometry-based assays and Amylite, are also described along with the relevant published data available regarding the performance of each assay.

Improved long-term survival rate in the responders to bortezomib, cyclophosphamide, dexamethasone induction therapy in a transplant-eligible cohort of predominantly middle-age multiple myeloma patients

BACKGROUND

Multiple myeloma (MM) represents the second most common hematologic malignancy (15%). Induction with bortezomib, cyclophosphamide, and dexamthasone VCd (d: low dose dexamthasone) regimen is widely used due to its high effectiveness, low toxicity and good tolerability, particularly with renal impairment. Real-world data on the use of VCD in clinical practice is lacking.

OBJECTIVES

Evaluate the real-world experience of the VCD regimen.

DESIGN

Retrospective.

SETTING

Tumor registry database of tertiary cancer care center.

PATIENTS AND METHODS

newly diagnosed MM patients who received VCD induction and underwent autologous stem cell transplant (ASCT) from July 2007 to July 2020.

MAIN OUTCOME MEASURES

response evaluation, progression-free survival (PFS) and overall survival (OS).

SAMPLE SIZE

87 patients.

RESULTS

Of 102 patients who started induction with VCd, 87 patients experienced a partial response or more overall response rate of 85%). The median age of these 87 patients at diagnosis was 52 years, of which 29.9% presented with renal impairment and 60.3% of patients had stage 2 by the Revised International Staging System (R-ISS). Patients with a standard cytogenetic risk achieved a better response compared to those with a poor cytogenetic risk (P=.044). The post-induction response rates were 6.9% stringent complete remission (sCR), 35% complete remission (CR); 41.4% very good partial response (VGPR), and 16.1% partial response (PR), respectively; the response rates became greater for sCR and CR post-transplantation at day 100 with 16.1% sCR, 35.6% CR, 32.2% VGPR and 16.1% PR, respectively. The median PFS was 49 months and 5 years OS was 84%. PFS was better in patients who achieved sCR vs PR (83 vs 35 months, P=.037). High LDH, high-risk cytogenetic and stage 3 R-ISS showed a worse median PFS and OS.

CONCLUSIONS

VCD induction in newly diagnosed MM is highly effective, convenient, tolerable and affordable regimen, especially in low and middle-income countries with limited resources, also with favorable outcomes and survival. while those who did not respond successfully shifted to VRD or VTD.

LIMITATIONS

The usual limitations of a retrospective analysis using registry-level data, no data on quality of life.

Impact of daratumumab on stem cell mobilization and collection, engraftment and early post-transplant complications among multiple myeloma patients undergoing autologous stem cell transplantation

Autologous stem cell transplantation (ASCT) remains a standard therapy for multiple myeloma (MM) patients. Our study aimed to assess the impact of daratumumab-containing induction on stem cell (SC) mobilization, apheresis and hospitalization. We evaluated 200 newly diagnosed MM patients that were mobilized for SC collection and which received induction with (N = 40) or without daratumumab (N = 160). Dara group patients required more frequent use of plerixafor, larger collection volumes, and had lower SC yield. 87.5% (35/40) of dara group patients achieved the planned yield of ≥ 5 × 10^6 CD34+/kg for at least one transplant compared to 96.2% (154/160) of patients in the non-dara group. Dara group patients had delayed hematopoietic recovery (11 vs 10 days for PMN > 0.5 × 10E9/l), required more transfusions (4 vs 2 plts), prolonged hospitalization (20 vs 18 days), more febrile episodes and prolonged antibiotic administration. Despite daratumumab effect patients finally achieved a successful stem cell collection and proceeded to transplant.

Impact of residual tumor cells in the stem cell collection on multiple myeloma patients receiving autologous stem cell transplantation

Autologous stem cell transplantation (ASCT) is the standard therapy for patients with transplant-eligible multiple myeloma (TEMM). However, the ideal depth of response required before ASCT and the impact of residual tumor cells in the stem cell collection (SCC) on survival remains unclear. Here we collected data of 89 patients with TEMM undergoing ASCT and analyzed the minimal residual disease of SCC (cMRD) and bone marrow (BM) (mMRD) before transplantation. Before ASCT, 31.5% and 76.4% of patients achieved MRD negativity in BM and SCC, respectively. Tumor cells were less in SCC samples than that in BM samples. Neoplastic cells in SCC could be observed in patients with different responses after induction therapy, and there were no significant differences in the percentage and level of cMRD among these subgroups (P > 0.05). No correlation was found between the cMRD status and the response patients achieved after ASCT (P > 0.05). The median follow-up was 26.8 months. mMRD negativity before ASCT was associated with longer PFS (55.9 vs. 27.1 months; P = 0.009) but not OS (not reached vs. 58.9 months; P = 0.115). Patients with different cMRD statuses before ASCT experienced similar PFS (40.5 vs. 76.4 months for negativity vs. positivity; P = 0.685) and OS (not reached vs. 58.8 months for negativity vs. positivity; P = 0.889). These results suggested that detectable cMRD does not significantly predict the inferior post-ASCT response or shorter survival, and patients are eligible to undergo ASCT upon achieving partial response.

A phase 1/2 of carfilzomib and melphalan conditioning for autologous stem cell transplantation for multiple myeloma (CARAMEL)

In this phase 1/2 study, carfilzomib was added to high-dose melphalan conditioning prior to autologous stem cell transplantation (ASCT) in patients with multiple myeloma that had been treated with ≤2 prior lines of therapy. Carfilzomib was escalated at doses of 27, 36, 45, and 56 mg/m2 on days -6, -5, -2, and -1 before ASCT in the phase 1 component of the study. In addition, all the patients received melphalan 100 mg/m2 on days -4 and -3. The primary endpoint of the phase 1 component was to identify the maximum tolerated dose, and the primary endpoint of the phase 2 component was the rates of complete response (≥CR) at 1 year after ASCT. The phase 1 dose escalation cohort included 14 patients, and 35 patients were included in the phase 2 cohort. The maximum tested dose was 56 mg/m2 (MTD). The median time from diagnosis to study enrollment was 5.8 (range 3.4-88.4) months, and 16% of patients had obtained a ≥CR prior to ASCT. The best response within 1 year after ASCT was a ≥ CR rate in 22% for the entire cohort, and 22% for patients treated at the MTD. The ≥VGPR rates improved from 41% before ASCT to 77% by 1 year after ASCT. One patient had a grade 3 renal adverse event, and renal function returned to baseline with supportive care. The rate of grade 3-4 cardiovascular toxicity was 16%. The addition of carfilzomib to melphalan conditioning was safe and resulted in deep responses after ASCT.

Outcomes of young adults (aged ≤ 40 years) with newly diagnosed multiple myeloma after up-front autologous stem cell transplant

Multiple myeloma (MM) primarily affects older patients. There are scarce data on the outcomes of young adults undergoing autologous transplantation (auto-HCT). In this single-centre analysis, we included 117 younger patients, with a median age of 37 years (range 22-40) at transplant. Seventeen (15%) patients had high-risk cytogenetics. Before transplant, 10% of patients achieved ≥CR and 44% achieved ≥VGPR. At best post-transplant response, 56% and 77% of patients achieved ≥CR and ≥VGPR respectively. With a median follow-up for survivors of 72.6 months (range 0.9-238.0), median PFS and OS were 43.1 months (95% CI 31.2-65.0) and 146.6 months (95% CI 100.0-208.1) respectively. Patients who underwent auto-HCT after 2010 had better median PFS (84.9 months vs. 28.2 months, p < 0.001) and OS (NR vs. 91.8 months, p < 0.001) compared with those transplanted earlier. In multi-variate analysis, achieving ≥CR as best post-transplant response was associated with improved PFS (HR [95% CI] 0.55 [0.32-0.95], p = 0.032), while achieving ≥VGPR was predictive of superior OS (0.32 [0.16-0.62], p < 0.001). Three patients (3%) developed a second primary malignancy. Younger MM patients had durable survival after auto-HCT, which further improved after the availability of novel anti-myeloma drugs in recent years. Depth of response following transplant remains a key predictor of survival.

Breaking through Multiple Myeloma: A Paradigm for a Comprehensive Tumor Ecosystem Targeting

Multiple myeloma (MM) is a cancerous condition characterized by the proliferation of plasma cells within the hematopoietic marrow, resulting in multiple osteolytic lesions. MM patients typically experience bone pain, kidney damage, fatigue due to anemia, and infections. Historically, MM was an incurable disease with a life expectancy of around three years after diagnosis. However, over the past two decades, the development of novel therapeutics has significantly improved patient outcomes, including response to treatment, remission duration, quality of life, and overall survival. These advancements include thalidomide and its derivatives, lenalidomide and pomalidomide, which exhibit diverse mechanisms of action against the plasma cell clone. Additionally, proteasome inhibitors such as bortezomib, ixazomib, and carfilzomib disrupt protein degradation, proving specifically toxic to cancerous plasma cells. Recent advancements also involve monoclonal antibodies targeting surface antigens, such as elotuzumab (anti-CS1) and daratumumab (anti-CD38), bispecific t-cell engagers such as teclistamab (anti-BCMA/CD3) and Chimeric antigen receptor T (CAR-T)-based strategies, with a growing focus on drugs that exhibit increasingly targeted action against neoplastic plasma cells and relevant effects on the tumor microenvironment.

Minimal Residual Disease in Multiple Myeloma: Past, Present, and Future

Responses to treatment have improved over the last decades for patients with multiple myeloma. This is a consequence of the introduction of new drugs that have been successfully combined in different clinical contexts: newly diagnosed, transplant-eligible or ineligible patients, as well as in the relapsed/refractory setting. However, a great proportion of patients continue to relapse, even those achieving complete response, which underlines the need for updated response criteria. In 2014, the international myeloma working group established new levels of response, prompting the evaluation of minimal residual disease (MRD) for those patients already in complete or stringent complete response as defined by conventional serological assessments: the absence of tumor plasma cells in 100,000 total cells or more define molecular and immunophenotypic responses by next-generation sequencing and flow cytometry, respectively. In this review, we describe all the potential methods that may be used for MRD detection based on the evidence found in the literature, paying special attention to their advantages and pitfalls from a critical perspective.

Revisiting checkpoint inhibitors for myeloma: maintenance after stem cell transplant

Multiple myeloma is a hematologic malignancy of plasma cells that manifests with bone marrow tumors causing lytic bone lesions. Autologous stem cell transplantation (ASCT) after high-dose chemotherapy and followed by prolonged maintenance therapy with lenalidomide (LEN) is an effective standard-of-care therapy for multiple myeloma. However, most patients ultimately relapse. Rational combination strategies that address immune dysfunction may prolong the durability of ASCT. In this issue of the JCI, Minnie and colleagues investigated the addition of a checkpoint inhibitor to LEN maintenance therapy after ASCT. They found that the immune checkpoint TIGIT was an optimal target in patient samples. In a syngeneic, immunocompetent multiple myeloma mouse model, blockade of TIGIT synergized with LEN maintenance by inducing immune protection, characterized in part by the expansion of polyfunctional T cells in the bone marrow. The treatment enhanced durable antimyeloma efficacy and has translatable implications.

Role of serum-free light chain assay for defining response and progression in immunoglobulin secretory multiple myeloma

The International Myeloma Working Group (IMWG) guidelines recommend using electrophoresis and immunofixation to define response and progressive disease (PD) in immunoglobulin (Ig) secretory multiple myeloma (Ig-MM), whereas the role of serum-free light chain (sFLC) is controversial. We retrospectively analyzed the value of adding sFLC assays in the definition of response and PD according to IMWG criteria in 339 Ig-MM patients treated with a first-line novel agent-based therapy (median follow-up 54 months). sFLC PD was defined according to conventional criteria plus increased sFLC levels, or sFLC escape (sFLCe); progression/sFLCe-free survival (ePFS) was the time from the start of treatment to the date of first PD or sFLCe, or death; overall survival after PD/sFLCe (OS after Pe) was the time from first PD or sFLCe to the date of death. 148 (44%) patients achieved a complete response and 198 (60%) a normal sFLC ratio (sFLCR). sFLCR normalization was an independent prognostic factor for extended PFS (HR = 0.46, p = 0.001) and OS (HR = 0.47, p = 0.006) by multivariable analysis. 175 (52%) patients experienced PD according to the IMWG criteria, whereas 180 (53%) experienced PD or sFLCe. Overall, a sFLCe was observed in 31 (9%) patients. Median PFS and ePFS were both equal to 36 (95% CI = 32-42, and 32-40, respectively) months. sFLC PD adversely affected the OS after Pe compared to PD with increasing monoclonal Ig only (HR = 0.52, p = 0.012). Our results support the inclusion of the sFLC assay for defining response and PD in Ig-MM.

Minimal residual disease detection by next-generation sequencing in multiple myeloma: Promise and challenges for response-adapted therapy

Assessment of minimal residual disease (MRD) is becoming a standard diagnostic tool for curable hematological malignancies such as chronic and acute myeloid leukemia. Multiple myeloma (MM) remains an incurable disease, as a major portion of patients even in complete response eventually relapse, suggesting that residual disease remains. Over the past decade, the treatment landscape of MM has radically changed with the introduction of new effective drugs and the availability of immunotherapy, including targeted antibodies and adoptive cell therapy. Therefore, conventional serological and morphological techniques have become suboptimal for the evaluation of depth of response. Recently, the International Myeloma Working Group (IMWG) introduced the definition of MRD negativity as the absence of clonal Plasma cells (PC) with a minimum sensitivity of <10⁻⁵ either by next-generation sequencing (NGS) using the LymphoSIGHT platform (Sequenta/Adaptative) or by next-generation flow cytometry (NGF) using EuroFlow approaches as the reference methods. While the definition of the LymphoSIGHT platform (Sequenta/Adaptive) as the standard method derives from its large use and validation in clinical studies on the prognostic value of NGS-based MRD, other commercially available options exist. Recently, the LymphoTrack assay has been evaluated in MM, demonstrating a sensitivity level of 10⁻⁵, hence qualifying as an alternative effective tool for MRD monitoring in MM. Here, we will review state-of-the-art methods for MRD assessment by NGS. We will summarize how MRD testing supports clinical trials as a useful tool in dynamic risk-adapted therapy. Finally, we will also discuss future promise and challenges of NGS-based MRD determination for clinical decision-making. In addition, we will present our real-life single-center experience with the commercially available NGS strategy LymphoTrack-MiSeq. Even with the limitation of a limited number of patients, our results confirm the LymphoTrack-MiSeq platform as a cost-effective, readily available, and standardized workflow with a sensitivity of 10⁻⁵. Our real-life data also confirm that achieving MRD negativity is an important prognostic factor in MM.

Longitudinal minimal residual disease assessment in multiple myeloma patients in complete remission – results from the NMSG flow-MRD substudy within the EMN02/HO95 MM trial

Background

Multiple myeloma remains an incurable disease with multiple relapses due to residual myeloma cells in the bone marrow of patients after therapy. Presence of small number of cancer cells in the body after cancer treatment, called minimal residual disease, has been shown to be prognostic for progression-free and overall survival. However, for multiple myeloma, it is unclear whether patients attaining minimal residual disease negativity may be candidates for treatment discontinuation. We investigated, if longitudinal flow cytometry-based monitoring of minimal residual disease (flow-MRD) may predict disease progression earlier and with higher sensitivity compared to biochemical assessments.

Methods

Patients from the Nordic countries with newly diagnosed multiple myeloma enrolled in the European-Myeloma-Network-02/Hovon-95 (EMN02/HO95) trial and undergoing bone marrow aspiration confirmation of complete response, were eligible for this Nordic Myeloma Study Group (NMSG) substudy. Longitdudinal flow-MRD assessment of bone marrow samples was performed to identify and enumerate residual malignant plasma cells until observed clinical progression.

Results

Minimal residual disease dynamics were compared to biochemically assessed changes in serum free light chain and M-component. Among 20 patients, reaching complete response or stringent complete response during the observation period, and with ≥3 sequential flow-MRD assessments analysed over time, increasing levels of minimal residual disease in the bone marrow were observed in six cases, preceding biochemically assessed disease and clinical progression by 5.5 months and 12.6 months (mean values), respectively. Mean malignant plasma cells doubling time for the six patients was 1.8 months (95% CI, 1.4–2.3 months). Minimal malignant plasma cells detection limit was 4 × 10–5.

Conclusions

Flow-MRD is a sensitive method for longitudinal monitoring of minimal residual disease dynamics in multiple myeloma patients in complete response. Increasing minimal residual disease levels precedes biochemically assessed changes and is an early indicator of subsequent clinical progression.

Trial registration

NCT01208766

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09184-1.

Tumor Reduction in Multiple Myeloma: New Concepts for New Therapeutics

The development of new resources for a more accurate diagnosis and response assessment in multiple myeloma has been a long process for decades, mainly since the middle of the 20th century. During this time, the succession of technical advances has run parallel to the better knowledge of disease biology and the availability of novel therapeutic strategies. The cornerstone of standardized criteria to uniformly evaluate the disease response in myeloma dates back to the 1990s when the key role of complete remission was established. Since then, different updates have been implemented according to available scientific evidences not always without certain controversies. The progressive improvements in survival results of myeloma patients and the growing quality of responses due to the novel therapies have led to the need of developing new tools for better monitoring of tumor burden. In this way, the concept of minimal residual disease and its key value based on the prognostic significance and the clinical relevance has been consolidated during the last years, overcoming the value of conventional response criteria or classical adverse prognosis markers. Nevertheless, its precise role in the clinical management of myeloma patients to detect early treatment failure and trigger early rescue strategies is still pending to be defined. In this review, we revisit the major milestones in the understanding of tumor reduction in multiple myeloma until the most recent imaging techniques or liquid biopsy approaches, including a critical view of conventional response criteria, whose backbone has remained unchanged during the last 20 years.

Minimal Residual Disease Assessment in Multiple Myeloma Patients: Minimal Disease With Maximal Implications

Multiple Myeloma (MM), the second most common hematologic malignancy, has been the target of many therapeutic advances over the past two decades. The introduction of novel agents, such as proteasome inhibitors, immunomodulatory drugs, and monoclonal antibodies, along with autologous hematopoietic stem cell transplantation (ASCT) in the current standard of care, has increased the median survival of myeloma patients significantly. Nevertheless, a curative treatment option continues to elude us, and MM remains an incurable disease, with patients relapsing even after achieving deep conventionally defined responses, underscoring the need for the development of sensitive methods that will allow for proper identification and management of the patients with a higher probability of relapse. Accurate detection of Minimal Residual Disease (MRD) from a bone marrow biopsy represents a relatively new approach of evaluating response to treatment with data showing clear benefit from obtaining MRD(-) status at any point of the disease course. As life expectancy for patients with MM continues to increase and deep responses are starting to become the norm, establishing and refining the role of MRD in the disease course is more relevant than ever. This review examines the different methods used to detect MRD and discusses future considerations regarding the implementation in day-to-day clinical practice and as a prospective primary endpoint for clinical trials.

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.

Relationship of tumor load parameters before and after autologous stem cell transplantation with clinical prognosis in transplant-eligible patients with multiple myeloma: A retrospective analysis

We retrospectively examined 57 patients with multiple myeloma who underwent autologous stem cell transplantation (ASCT) at our institution. A receiver-operating characteristic curve (ROC) analysis showed that the reduction rate of quantitative serum monoclonal protein (M-protein) before ASCT and the difference in involved and uninvolved free light chains (dFLC) 30 days after ASCT, respectively, had the greatest predictive value for all patients (area under the curve [AUC] 0.791 and 0.660, respectively). Based on the ROC curve-based cutoff values of tumor burden parameters, progression-free survival (PFS) in the high serum M-protein reduction (≥90 %) group was significantly better than that in the low serum M-protein reduction group (<90 %) (2-year PFS 79.5 % vs. 17.0 %, p < 0.001), but there were no significant differences in PFS between the low (<5.2 mg/L) and high (≥5.2 mg/L) dFLC groups (2-year PFS, 72.0 % vs. 46.0 %; p = 0.149). A multivariate analysis identified the reduction in serum M-protein as an independent predictive factor before ASCT for PFS (hazard ratio [HR] 0.287, p = 0.022) and high dFLC on day 30 after ASCT for PFS (HR 3.902, p = 0.040). These results demonstrate that a good prognosis can be expected with a reduction of serum M-protein before and after ASCT.

Addition of daratumumab to multiple myeloma backbone regimens significantly improves clinical outcomes: a systematic review and meta-analysis of randomised controlled trials

Daratumumab has shown clinical benefit in multiple myeloma. We aimed to evaluate the safety and efficacy of adding daratumumab to backbone anti-myeloma treatments. Systematic search was performed up to August 2021 to identify randomised controlled trials comparing the outcomes of backbone therapy with and without daratumumab in relapsed/refractory and newly diagnosed myeloma (RRMM and NDMM, respectively). Odds ratios (ORs) and hazard ratios (HRs) were calculated with 95% confidence intervals (CIs). Primary outcomes were death or disease progression, minimal residual disease (MRD) negativity, and stringent complete response (sCR). Secondary outcomes were complete response or better and safety endpoints prespecified in the study protocol: PROSPERO (CRD42020222904). In NDMM, MRD negativity [OR = 3.61 (CI 2.33-5.61)] and sCR [OR = 2.29 (CI 1.49-3.51)] were more likely and death or disease progression [HR = 0.47 (CI 0.39-0.57)] was less likely to occur with daratumumab compared to control. Regarding RRMM, MRD negativity [OR = 5.43 (CI 2.76-10.66)] and sCR [OR = 3.08 (CI 2.00-4.76)] were more likely and death or disease progression was less likely [HR = 0.50 (CI 0.37-0.67)] with daratumumab compared to control. The addition of daratumumab has shown high clinical efficacy and acceptable toxicity profile for the treatment of NDMM and RRMM regarding the endpoints examined.

Minimal Residual Disease in Multiple Myeloma: Ready for Prime Time?

ABSTRACT

Minimal residual disease (MRD) techniques are essential to identify the small clonal fraction within and outside the bone marrow. In the last years, evidence regarding their prognostic role for the evaluation of the depth of response of current treatment strategies has grown rapidly. Consequently, MRD was incorporated in an increasing number of clinical trials for multiple myeloma patients, also as primary endpoint, and even to guide therapeutic choices. A robust correlation between MRD negativity and survival was established. Yet, several issues regarding MRD evaluation remain to be addressed: from the optimal and more cost-effective techniques for its assessment and its harmonization worldwide to its use in clinical practice to its impact on treatment modulation. This review focuses on the available evidence supporting the use of MRD status for the management of multiple myeloma patients and on open issues that still need an answer.

Minimal Residual Disease in Multiple Myeloma: Something Old, Something New

The game-changing outcome effect, due to the generalized use of novel agents in MM, has cre-ated a paradigm shift. Achieving frequent deep responses has placed MM among those neoplasms where the rationale for assessing MRD is fulfilled. However, its implementation in MM has raised specific questions: how might we weight standard measures against deep MRD in the emerging CAR-T setting? Which high sensitivity method to choose? Are current response criteria still useful? In this work, we address lessons learned from the use of MRD in other neoplasms, the steps followed for the harmonization of current methods for comprehensively measuring MRD, and the challenges that new therapies and concepts pose in the MM clinical field.

Disease heterogeneity, prognostication and the role of targeted therapy in multiple myeloma

Multiple myeloma (MM) is a clonal plasma cell malignancy with a heterogeneous disease course. Insights into the genetics of the disease have identified certain high-risk cytogenetic features that are associated with adverse outcomes. While the advances in therapy have translated into dramatic improvements in the outcome of patients with MM, those with high-risk genetic features continue to perform poorly. This has resulted in a need for clinical trials focusing on the high-risk subgroup of MM as they search for additional biomarkers and therapeutic targets continue. In this review, we discuss the currently existing data on prognostic and predictive biomarkers in MM and speculate the role of treatment stratification based on the genetic features of the disease.

Quantification of measurable residual disease in patients with multiple myeloma based on the IMWG response criteria

Stringent complete response (sCR) is defined as a deeper response than complete response (CR) in multiple myeloma. Whether achieving sCR correlates with better survival remains controversial. We evaluated the outcomes in patients with intact immunoglobulin multiple myeloma (IIMM) and light chain multiple myeloma (LCMM) who achieved a very good partial response (VGPR) or better. Multicolour flow cytometry was used to assess the depth of response. LCMM patients with sCR had significantly lower measurable residual disease (MRD) levels than those with CR (median MRD: 7.9 × 10^-4 vs. 5.6 × 10^-5, P < 0.01). Nonetheless, no significant difference was observed in MRD levels across the responses in groups of patients with IIMM (VGPR vs. CR: 3.5 × 10^-4 vs. 7.0 × 10^-5, P = 0.07; CR vs. sCR: 7.0 × 10^-5 vs. 5.4 × 10^-5, P = 0.81. In accordance with MRD levels, the median overall survival of patients with sCR was significantly longer (sCR, CR, VGPR; not reached, 41 months, and 58 months, respectively; VGPR vs. CR, P = 0.83; CR vs. sCR, P = 0.04) in LCMM, but not in IIMM (sCR, CR, VGPR; not reached, 41 months, and not reached, respectively; VGPR vs. CR, P = 0.59; CR vs. sCR; P = 0.10). Our results show that sCR represents a deeper response that correlates with longer survival in patients with LCMM, but not IIMM.

Utility of serum free light chain ratio in response definition in patients with multiple myeloma

Patients with an abnormal sFLC ratio because of LC suppression have outcomes similar to those with a normal ratio. sFLC ratio has prognostic value in patients achieving CR who have an absence of clonal BMPCs assessed by MFC.

Daratumumab, lenalidomide, bortezomib, and dexamethasone for transplant-eligible newly diagnosed multiple myeloma: the GRIFFIN trial

Lenalidomide, bortezomib, and dexamethasone (RVd) followed by autologous stem cell transplantation (ASCT) is standard frontline therapy for transplant-eligible patients with newly diagnosed multiple myeloma (NDMM). The addition of daratumumab (D) to RVd (D-RVd) in transplant-eligible NDMM patients was evaluated. Patients (N = 207) were randomized 1:1 to D-RVd or RVd induction (4 cycles), ASCT, D-RVd or RVd consolidation (2 cycles), and lenalidomide or lenalidomide plus D maintenance (26 cycles). The primary end point, stringent complete response (sCR) rate by the end of post-ASCT consolidation, favored D-RVd vs RVd (42.4% vs 32.0%; odds ratio, 1.57; 95% confidence interval, 0.87-2.82; 1-sided P = .068) and met the prespecified 1-sided α of 0.10. With longer follow-up (median, 22.1 months), responses deepened; sCR rates improved for D-RVd vs RVd (62.6% vs 45.4%; P = .0177), as did minimal residual disease (MRD) negativity (10-5 threshold) rates in the intent-to-treat population (51.0% vs 20.4%; P < .0001). Four patients (3.8%) in the D-RVd group and 7 patients (6.8%) in the RVd group progressed; respective 24-month progression-free survival rates were 95.8% and 89.8%. Grade 3/4 hematologic adverse events were more common with D-RVd. More infections occurred with D-RVd, but grade 3/4 infection rates were similar. Median CD34+ cell yield was 8.2 × 106/kg for D-RVd and 9.4 × 106/kg for RVd, although plerixafor use was more common with D-RVd. Median times to neutrophil and platelet engraftment were comparable. Daratumumab with RVd induction and consolidation improved depth of response in patients with transplant-eligible NDMM, with no new safety concerns. This trial was registered at www.clinicaltrials.gov as #NCT02874742.

Minimal residual disease in multiple myeloma: defining the role of next generation sequencing and flow cytometry in routine diagnostic use

For patients diagnosed with multiple myeloma (MM) there have been significant treatment advances over the past decade, reflected in an increasing proportion of patients achieving durable remissions. Clinical trials repeatedly demonstrate that achieving a deep response to therapy, with a bone marrow assessment proving negative for minimal residual disease (MRD), confers a significant survival advantage. To accurately assess for minute quantities of residual cancer requires highly sensitive methods; either multiparameter flow cytometry or next generation sequencing are currently recommended for MM response assessment. Under optimal conditions, these methods can detect one aberrant cell amongst 1,000,000 normal cells (a sensitivity of 10^-6). Here, we will review the practical use of MRD assays in MM, including challenges in implementation for the routine diagnostic laboratory, standardisation across laboratories and clinical trials, the clinical integration of MRD status assessment into MM management and future directions for ongoing research.

Defining the undetectable: The current landscape of minimal residual disease assessment in multiple myeloma and goals for future clarity

Multiple Myeloma, the second most prevalent hematologic malignancy, yet lacks an established curative therapy. However, overall response rate to modern four-drug regimens approaches 100%. Major efforts have thus focused on the measurement of minute quantities of residual disease (minimal residual disease or MRD) for prognostic metrics and therapeutic response evaluation. Currently, MRD is assessed by flow cytometry or by next generation sequencing to track tumor-specific immunoglobulin V(D)J rearrangements. These bone marrow-based methods can reach sensitivity thresholds of the identification of one neoplastic cell in 1,000,000 (10-6). New technologies are being developed to be used alone or in conjunction with established methods, including peripheral blood-based assays, mass spectrometry, and targeted imaging. Data is also building for MRD as a surrogate endpoint for overall survival. Here, we will address the currently utilized MRD assays, challenges in validation across labs and clinical trials, techniques in development, and future directions for successful clinical application of MRD in multiple myeloma.

Current Treatment Strategies for Multiple Myeloma

The treatment of multiple myeloma (MM) continues to evolve with the approval of numerous agents over the past decade. Advances in treatment have led to the incorporation of these newer therapies into the treatment paradigm, with improvements in overall survival and the possibility of deep responses including a minimal residual disease-negative state. The strategy of triplet therapies for patients with newly diagnosed MM, followed by high-dose chemotherapy and autologous stem-cell transplantation for eligible patients, and subsequently consolidation and maintenance therapy, is the current treatment roadmap for patients. However, patients with MM will ultimately develop refractoriness to antimyeloma therapies. In this article, we summarize our current practice of managing patients with MM. We highlight our approach to patients with newly diagnosed MM who are transplantation eligible and ineligible and highlight risk-adapted strategies for these patients. In addition, we discuss our approach to the management of patients with relapsed or refractory MM. Last, we review standard therapies and emerging strategies such as targeted approaches, immune-based therapies, and drugs with novel mechanisms of action. Trials evaluating chimeric antigen receptor T cells targeting B-cell maturation antigen are ongoing and are only one of several novel approaches targeting cell maturation antigen, which include the use of bispecific T-cell engager antibodies and antibody drug conjugates. Emerging therapies offer the promise of more individualized approaches in the management of patients with MM and ultimately may result in the possibility of being one step closer to curing patients with MM.

Measurable residual disease in multiple myeloma and light chain amyloidosis: more than meets the eye

The emergence of highly effective multiple myeloma (MM) treatments may bring cure within reach and highlights the need for highly sensitive measurable residual disease (MRD) techniques to replace conventional response assessments. MRD is being incorporated as an endpoint in an increasing number of studies and had been repeatedly shown to be both a predictive marker of response to treatment and a prognostic marker for future relapse. However, those results should be cautiously interpreted due to non-uniform reporting and the need for longer follow up to assess for sustained MRD negativity. This review aims to critically analyze the key MRD aspects including the current evidence supporting the use of MRD in clinical practice and the pitfalls of the various methods used to assess MRD. The utility of MRD for light chain (AL) amyloidosis will also be discussed.

Multiple myeloma

Multiple myeloma is the second most common haematological malignancy in high-income countries, and typically starts as asymptomatic precursor conditions-either monoclonal gammopathy of undetermined significance or smouldering multiple myeloma-in which initiating genetic abnormalities, such as hyperdiploidy and translocations involving the immunoglobulin heavy chain, are already present. The introduction of immunomodulatory drugs, proteasome inhibitors, and CD38-targeting antibodies has extended survival, but ultimately the majority of patients will die from their disease, and some from treatment-related complications. Disease progression and subsequent relapses are characterised by subclonal evolution and increasingly resistant disease. Patients with multiple myeloma usually have hypercalcaemia, renal failure, anaemia, or osteolytic bone lesions-and a detailed diagnostic investigation is needed to differentiate between symptomatic multiple myeloma that requires treatment, and precursor states. Risk stratification using both patient-specific (eg, performance status) and disease-specific (eg, presence of high-risk cytogenetic abnormalities) is important for prognosis and to define the best treatment strategy. Current research strategies include the use of minimal residual disease assays to guide therapy, refining immunotherapeutic approaches, and intercepting disease early in smouldering multiple myeloma.

Autologous stem cell transplantation (ASCT) outcome for multiple myeloma in a tertiary referral centre in Malaysia

Background

Multiple Myeloma (MM) is characterized by the presence of clonal plasma cells. These often result in complications including bone destruction, hypercalcemia, renal insufficiency, and anaemia. Induction with a triplet or quadruplet regimen followed by autologous stem cell transplantation (ASCT) has been the standard of care for transplant eligible patients to achieve durable remission.

Purpose

This is a retrospective analytical study to determine the outcome of Multiple Myeloma patients who underwent ASCT in Ampang Hospital.

Materials and Methods

We included a 5-year cohort of patients transplanted from 1st July 2014 to 30th June 2019. Data were obtained through electronic medical records. Prognostic factors for progression-free survival (PFS) and overall survival (OS) were analyzed using simple and multiple Cox proportional hazard regression analysis. All analyses were done using software R version 3.6.2 with validated statistical packages.

Results

139 patients were analyzed. The median age at transplant was 56 years old and 56.1% are males (n＝78). The most common subtype is IgG Kappa (n＝67, 48.2%). Only 93 patients in which the International Staging System (ISS) could be determined, and among them, 33.3% of patients (n＝31) have advanced stage Ⅲ disease. The most common induction received before ASCT was a bortezomib based regimen and/or an immunomodulatory (IMiD) based regimen. 63.3% of patients achieved at least a very good partial response (VGPR) before ASCT. Most patients received myeloablative conditioning (MAC) (n＝119, 85.6%). The mean cell dose is 3.68×10⁶/kg. The median time to engraftment was 11 days for both platelet and absolute neutrophil count (ANC). With the median follow-up of 17.3 (range, 6.2-33.4) months, the median OS and PFS were not reached. The 1-year and 2-year PFS were 75% (95% CI 66-82%) and 52% (95% CI 42-62%), respectively. The 1-year and 2-year OS were 82% (95% CI 74-88%) and 70% (95% CI 60-78%), respectively. 6 patients (4.3%) had transplant-related mortality (TRM). IgA subtype was found to adversely affect PFS. Maintenance therapy and the absence of renal impairment was associated with better PFS and OS.

Discussion and Conclusions

Our study found that ASCT following induction treatment is safe and beneficial to achieve a deeper remission status. In our study, the addition of maintenance therapy is associated with an improved outcome in PFS and OS.

Elotuzumab-based maintenance therapy following autologous stem cell transplant in multiple myeloma deepens post-transplant responses

BACKGROUND

Post-transplant maintenance provides progression-free survival benefit in multiple myeloma (MM). Here we report our institution's experience with elotuzumab-based maintenance following autologous stem cell transplant.

METHODS

We retrospectively evaluated the outcomes of MM patients who were started on elotuzumab-based maintenance (elotuzumab/lenalidomide/dexamethasone, elotuzumab/bortezomib/dexamethasone, or elotuzumab/bortezomib/methylprednisolone) following transplant (N = 7). Baseline characteristics, treatment response, survival, and adverse events were reviewed.

RESULTS

Median age was 68 (56-81) years at the time of transplant, and median lines of induction therapy was 2 (1-6). Three patients (42.9%) had high-risk cytogenetics and five (71.4%) had stage II or greater disease at diagnosis. At a median follow-up of 24 months (12-50), five patients (71.4%) had improvement of quality of response, with a combined CR or VGPR rate increasing from 57.1% to 100% (CR = 3, VGPR = 4). All patients were alive without relapse or progression at the time of this analysis. Grade 3-4 adverse events were observed in three (42.9%) patients. None of the patients discontinued the treatment due to intolerance.

CONCLUSIONS

Our study demonstrates that elotuzumab-based maintenance may deepen response post-transplant in MM and can be safely administered even in older patients. Given its unique action and rare side effects, further studies of elotuzumab in the post-transplant setting are warranted.

Challenges and Strategies in the Management of Multiple Myeloma in the Elderly Population

PURPOSE OF REVIEW

Approximately one half of the patient-population in multiple myeloma (MM) is > 70 years at diagnosis. Despite notable strides in the management and improved survival, MM remains incurable, with an increasing proportion of elderly patients comprising the relapsed-refractory cohort.

RECENT FINDINGS

The arbitrary age cutoff at 65 years to define the elderly patient-population has evolved to a more nuanced categorization, incorporating a comprehensive assessment for determining frailty prior to commencing treatment. This step is critical in determining the therapy-intensity, including transplant-eligibility, to minimize toxicity. Dose-modifications are crucial, as the merits of continuous therapy are becoming evident in this patient-population. Bortezomib, lenalidomide, and dexamethasone (VRd) combination has emerged as standard of care for newly diagnosed MM. Fixed-duration Rd followed by reduced-dosed continuous R may be considered in select frail patients with standard-risk MM. Herein, we review the unique challenges encountered in elderly MM and discuss strategies for optimal management.

Impact of Pre-transplant and Post-transplant Remission Status of Patients on Survival in Newly Diagnosed Multiple Myeloma

The overall survival (OS) in patients with multiple myeloma (MM) has increased in the last decade due to the introduction of proteasome inhibitors, immunomodulatory drugs and monoclonal antibodies as well as an extensive combination of autologous stem cell transplantation (ASCT) for suitable patients. The objective of this study was to examine the impact of pre-transplant and post-transplant remission status of patients on survival in newly diagnosed multiple myeloma. Two hundred and four patients with newly diagnosed MM who received an ASCT in our HSC transplant center at Hacettepe University Hospital between the years of 2001 and 2018 were evaluated in a retrospective manner. The median follow-up period was 35.9 months (range 4.2-206.4) for the entire group. The 5-year OS for pre-transplant remission status CR/VGPR patients and pre-transplant remission status PR or less patients were 79% and 68%, respectively (p = 0.09). The 5-year PFS for pre-transplant remission status CR/VGPR patients and pre-transplant remission status PR or less patients were 62% and 45%, respectively (p = 0.23). The 5-year OS for post-transplant remission status CR/VGPR group was 72% and for post-transplant remission status PR or less group was 60% (p = 0.02). The 5-year PFS in post-transplant remission status CR/VGPR patients was 48% and post-transplant remission status PR or less patients was 36% (p = 0.03). This study focuses on determination of survival outcome based on the best response obtained before and after ASCT and particularly highlights the significance of reaching CR and VGPR.

Bortezomib and Vorinostat Therapy as Maintenance Therapy after Autologous Transplant for Multiple Myeloma

BACKGROUND

In multiple myeloma (MM), relapse is a frequent complication after autologous hematopoietic stem cell transplant (ASCT). To reduce the risk of relapse, additional therapy has been added post-ASCT. In a nontransplant relapse setting, the combination of intravenous bortezomib and oral vorinostat (BV) was studied and showed efficacy. Therefore, it was reasonable to study this combination therapy post-ASCT.

PATIENTS AND METHODS

We report on BV given post-ASCT. All 30 patients underwent conditioning for ASCT with high-dose melphalan. After recovery from the acute transplant-related toxicity, BV therapy was started and given for a total of 12 (28-day) cycles.

RESULTS

The most common toxicities were hematological, gastrointestinal (diarrhea and nausea), fatigue, and peripheral neuropathy. The median follow-up for BV patients is 7.8 (range: 6.12-9.03) years. After BV therapy, 18 patients (60%) are alive, and 9 (30%) are alive without disease progression.

CONCLUSIONS

BV can be given post-ASCT with an acceptable toxicity profile and produces reasonable disease-free and overall survival rates. A randomized study comparing the BV regimen to single-agent lenalidomide or bortezomib is needed.

Bortezomib, thalidomide, and dexamethasone with or without daratumumab before and after autologous stem-cell transplantation for newly diagnosed multiple myeloma (CASSIOPEIA): a randomised, open-label, phase 3 study

BACKGROUND

Bortezomib, thalidomide, and dexamethasone (VTd) plus autologous stem-cell transplantation is standard treatment in Europe for transplant-eligible patients with newly diagnosed multiple myeloma. We evaluated whether the addition of daratumumab to VTd before and after autologous stem-cell transplantation would improve stringent complete response rate in patients with newly diagnosed multiple myeloma.

METHODS

In this two-part, randomised, open-label, phase 3 CASSIOPEIA trial, we recruited transplant-eligible patients with newly diagnosed multiple myeloma at 111 European sites. Patients were randomly assigned (1:1) to receive four pre-transplant induction and two post-transplant consolidation cycles of VTd alone (VTd group) or in combination with daratumumab (D-VTd group). The primary endpoint of part 1 was stringent complete response assessed 100 days after transplantation. Part 2 (maintenance) is ongoing. The trial is registered with ClinicalTrials.gov, number NCT02541383.

FINDINGS

Between Sept 22, 2015, and Aug 1, 2017, 1085 patients were enrolled at 111 European sites and were randomly assigned to the D-VTd group (n=543) or the VTd group (n=542). At day 100 after transplantation, 157 (29%) of 543 patients in the D-VTd group and 110 (20%) of 542 patients in the VTd group in the intention-to-treat population had achieved a stringent complete response (odds ratio 1·60, 95% CI 1·21-2·12, p=0·0010). 211 (39%) patients in the D-VTd group versus 141 (26%) in the VTd group achieved a complete response or better, and 346 (64%) of 543 versus 236 (44%) of 542 achieved minimal residual disease-negativity (10-5 sensitivity threshold, assessed by multiparametric flow cytometry; both p<0·0001). Median progression-free survival from first randomisation was not reached in either group (hazard ratio 0·47, 95% CI 0·33-0·67, p<0·0001). 46 deaths on study were observed (14 vs 32, 0·43, 95% CI 0·23-0·80). The most common grade 3 or 4 adverse events were neutropenia (28% vs 15%), lymphopenia (17% vs 10%), and stomatitis (13% vs 16%).

INTERPRETATION

D-VTd before and after autologous stem-cell transplantation improved depth of response and progression-free survival with acceptable safety. CASSIOPEIA is the first study showing the clinical benefit of daratumumab plus standard of care in transplant-eligible patients with newly diagnosed multiple myeloma.

FUNDING

The Intergroupe Francophone du Myélome and Dutch-Belgian Cooperative Trial Group for Hematology Oncology.

The impact of re-induction prior to salvage autologous stem cell transplantation in multiple myeloma

Autologous stem cell transplantation (ASCT) is an integral component of the therapeutic arsenal in multiple myeloma. Given that overall survival (OS) is comparable between patients receiving up-front or delayed ASCT, some opt to collect stem cells and postpone transplant until the time of disease progression (i.e. salvage ASCT). It is unknown if induction should be repeated prior to salvage ASCT, or if patients should proceed directly. We identified 234 patients who underwent salvage ASCT at our institution: 188 (80%) were re-induced, whereas 46 (20%) proceeded directly without re-induction. There was no significant difference in time to next therapy (TNT) or OS from Day 0 between the two groups. Patients who were re-induced had a nonsignificant trend towards a higher rate of complete response post-ASCT (45% vs. 33%, p= .12). In multivariate models, re-induction did not affect TNT/OS. In the subgroup of 188 patients who were re-induced, patients with relapsed/refractory disease at the time of ASCT had significantly shorter TNT/OS compared to patients with deeper pre-ASCT responses. In summary, there was no survival difference for patients who were re-induced before salvage ASCT. However, many factors affect the decision to re-induce, and prospective studies would be required to discern its role definitively.

Standardized Minimal Residual Disease Detection by Next-Generation Sequencing in Multiple Myeloma

Next-generation sequencing (NGS) has been applied to monitor minimal residual disease (MRD) in multiple myeloma (MM). Standardized DNA input and sequencing depth is essential for achieving a uniform sensitivity in NGS-based MRD study. Herein, the sensitivity of 10⁻⁵ was verified by a standardized experimental design based on triplicate measurements of 1 μg DNA input and 1 million sequencing reads using the LymphoTrack-MiSeq platform. MRD level was defined as the mean MRD burden of the triplicates. Two spike-in controls at concentrations of 0.001% tumor plasma cells (PC) for verifying the sensitivity of 10⁻⁵ and 0.01% (or 0.005%) for MRD normalization were systematically analyzed. The spike-in control of 0.001% MRD was consistently detected in all samples, confirming a sensitivity of 10⁻⁵. Moreover, this standardized NGS approach yielded MRD measurements concordant with serological response and comparable to allele-specific oligonucleotide (ASO) real-time quantitative (RQ)-PCR. Moreover, NGS showed an improved sensitivity and provided quantification of MRD for cases assigned “positive but not quantifiable” (PNQ) by ASO RQ-PCR, even without the use of patient-specific probes/primers. Issues regarding the specificity of myeloma-specific sequences as MRD target, optimal input for spike-in normalization, and interpretation of MRD from triplicates are discussed. Herein, the standardized LymphoTrack-MiSeq-based method is verified to carry a sensitivity of 10⁻⁵, hence an effective tool for MRD monitoring in MM. As only a small number of samples are tested here, further study with a larger number of patients is warranted.

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.

High-risk myeloma and minimal residual disease postautologous-HSCT predict worse outcomes

The aim of our study was to determine the impact of high-risk disease (HRD) and MRD on outcomes in myeloma patients receiving bortezomib-based induction followed by autologous hematopoietic stem cell transplant (auto-HSCT). HRD included t(4:14), t(14;16), del 17p, del 1p and/or amplification 1q by cytogenetics/FISH; all others were standard-risk disease (SRD). A subset of 165 newly diagnosed myeloma patients in a 2:1 ratio of HRD:SRD was generated using propensity score based nearest neighbor matching. Multiparametric flow cytometry (MFC) was used to detect MRD after auto-HSCT in select patients. MRD+ status at 3 months post auto-HSCT (hazard ratio (HR = 4.23, p = .028) and HRD (HR = 1.72, p = .026) were associated with a shorter PFS. Similarly, MRD+ 3 months post auto-HSCT (HR = 6.93, p = .08) and HRD (HR = 3.54, p < .001) and were associated with a shorter OS. Despite bortezomib-based induction, upfront auto-HSCT, and use of maintenance therapy, PFS and OS remained worse in MRD+ and HRD patients.

Responses in multiple myeloma should be assigned according to serum, not urine, free light chain measurements

The most recent update to the International Myeloma Working Group consensus criteria places a strong emphasis on the need for more sensitive haematological markers of response driven by the success of novel therapies. One such marker is serum free light chain (sFLC) analysis, which was first incorporated into the definition of stringent complete response in 2006. However, over the past decade there has been some reluctance to extend the role of the sFLC assays to replace 24 h urine electrophoresis for monitoring multiple myeloma (MM). In this review, we lay out the evidence in favour of serum over urine for monoclonal FLC measurements and propose modified criteria for response assignment in myeloma.

Minimal residual disease and log-reduction of plasma cells are associated with superior response after double autologous stem cell transplant in younger patients with multiple myeloma

BACKGROUND

Optimization of chemotherapy regimens in the treatment of multiple myeloma (MM) has led to increase the frequency of cases with complete response (CR). Nonetheless, many MM patients still experience relapse, suggesting that CR represents a suboptimal response criteria, and that new therapeutic strategies are needed after single transplant. However, the role of double autologous stem cell transplant (ASCT) as new adjunctive strategy remains to be elucidated. Indeed, we investigated the role of minimal residual disease (MRD) and log-reduction of plasma cells (PCs) as predictors of outcome and in quantifying the degree of tumor reduction after any ASCT.

METHODS

MRD and log-reduction were assessed by a six-color flow cytometry (FC) at different time-points: post induction, post first-, and post-second ASCT.

RESULTS

A significant difference was evidenced among the three time points for both log-reduction (P < 0.001) and MRD (P = 0.005). MRD levels after double ASCT were lower than MRD levels achieved after single ASCT (P = 0.005) and after induction (P < 0.001). Frequency of MRD positive patients after double ASCT was significantly lower rather than after the first ASCT (P = 0.008) and after induction (P = 0.004). Interestingly, a significant reduction of PFS was observed in patients with an unfavorable-risk cytogenetic (P < 0.001) and patients with MRD over 0.01% (P = 0.001) as well as log-reduction lower than 2.57 (P = 0.018) after double ASCT.

CONCLUSIONS

Our results show that a better clearance of myeloma cells is observed after the double ASCT, and a longer PFS is associated with a lower MRD. © 2018 International Clinical Cytometry Society.

Plasma cell proliferative index post-transplant is a powerful predictor of prognosis in myeloma patients failing to achieve a complete response

Myeloma patients failing to achieve a complete response post autologous stem cell transplantation are heterogeneous, some ultimately achieving deeper responses and prolonged remission, whilst others relapse rapidly with poor outcomes. We evaluated the prognostic impact of the plasma cell proliferative index (PCPI) post-therapy, in 382 patients with myeloma failing to achieve complete response at 100 days post-transplant. Sixty percent (n = 230) of patients had zero clonal or too few clonal plasma cells to accurately assess PCPI (No PCPI). The remaining 40% (n = 152) of patients had PCPI performed with 79% (n = 120) having a low PCPI and 21% (n = 32) having an elevated PCPI. Patients with an elevated PCPI had significantly shorter progression free and overall survival. The median PFS was 8 months for elevated PCPI vs. 19 months for low PCPI vs. 24 months for no PCPI (p < 0.0001). The median OS was 27 months for elevated PCPI vs. 79 months for low PCPI vs. not reached for no PCPI, p < 0.0001). On multivariable analysis post-therapy PCPI was an independent predictor of progression free and overall survival. The PCPI post-therapy is a powerful predictor of survival and risk stratifies myeloma patients failing to achieve complete response early in the disease course.

Minimal residual disease analysis in myeloma - when, why and where

The primary hurdle in the path to curing multiple myeloma (MM) is defining a validated minimal residual disease (MRD) and its utility in the therapeutic decision making. A better definition of MRD will aid in tailoring MM therapy further to address the clonal heterogeneity and genomic instability and overcome patient's ineffective immune surveillance. MRD analysis can define the logical endpoint for maintenance therapy, in addition also aids in providing a better clinical end point for studies comparing novel agents in myeloma. MRD is a surrogate for the survival in MM. Guidelines for global incorporation of MRD in myeloma are fraught with lack of standardization, universal availability and abridged physicians' understanding of MRD modalities. We aimed at addressing some of the frequently asked questions in the MRD assessment and will also place in perspective some arguments in favor of MRD assessment in routine practice and clinical trial scenario.

Interference of Therapeutic Monoclonal Antibodies With Routine Serum Protein Electrophoresis and Immunofixation in Patients With Myeloma: Frequency and Duration of Detection of Daratumumab and Elotuzumab

OBJECTIVES

We investigated the frequency and pattern of detection of therapeutic monoclonal antibodies (t-mAbs) daratumumab and elotuzumab by routine serum protein electrophoresis (SPE) and immunofixation (IF) in treated patients with myeloma.

METHODS

Detection of t-mAb was assessed in 22 patients by retrospective review of SPE/IF ordered prior to, during, and after 26 individual courses of therapy.

RESULTS

t-mAb was distinguishable from M-protein in 16 of 26 courses, with daratumumab detected in nine of nine and elotuzumab in six of seven patients. t-mAb was detected on first follow-up SPE/IF in 12 patients, with earliest detection 7 days after therapy initiation and latest detection 70 days after therapy. t-mAb persisted throughout induction therapy in most patients, with loss of detection during maintenance daratumumab.

CONCLUSIONS

When distinguishable from M-protein, t-mAbs are detectable in 93% of treated patients as soon as 7 days after the initial dose and are consistently observed throughout induction therapy, warranting increased monitoring and careful interpretation of SPE/IF.