The genomic profiling of high-risk smoldering myeloma patients treated with an intensive strategy unveils potential markers of resistance and progression.

Smoldering multiple myeloma (SMM) precedes multiple myeloma (MM). The risk of progression of SMM patients is not uniform, thus different progression-risk models have been developed, although they are mainly based on clinical parameters. Recently, genomic predictors of progression have been defined for untreated SMM. However, the usefulness of such markers in the context of clinical trials evaluating upfront treatment in high-risk SMM (HR SMM) has not been explored yet, precluding the identification of baseline genomic alterations leading to drug resistance. For this reason, we carried out next-generation sequencing and fluorescent in-situ hybridization studies on 57 HR and ultra-high risk (UHR) SMM patients treated in the phase II GEM-CESAR clinical trial (NCT02415413). DIS3, FAM46C, and FGFR3 mutations, as well as t(4;14) and 1q alterations, were enriched in HR SMM. TRAF3 mutations were specifically associated with UHR SMM but identified cases with improved outcomes. Importantly, novel potential predictors of treatment resistance were identified: NRAS mutations and the co-occurrence of t(4;14) plus FGFR3 mutations were associated with an increased risk of biological progression. In conclusion, we have carried out for the first time a molecular characterization of HR SMM patients treated with an intensive regimen, identifying genomic predictors of poor outcomes in this setting.

Papain-treated panels are a simple method for the identification of alloantibodies in multiple myeloma patients treated with anti-CD38-based therapies.

OBJECTIVES: To report our 2 years of experience navigating the interference of anti-CD38 monoclonal antibodies (MAs) in 33 patients and describe papain-treated panels as a complementary method to dithiothreitol (DTT). BACKGROUND: Novel anti-CD38 MAs are now approved or undergoing clinical trials to evaluate their activity in patients with multiple myeloma. A concern with the use of these drugs is that they interfere with blood bank tests in a group of patients who often require blood transfusions. METHODS: Clinical data and whole blood samples were collected from patients receiving daratumumab or isatuximab. Routine blood bank serological tests were performed. RESULTS: A total of 9·1% of patients presented with alloantibodies prior to treatment. All patients exhibited nonspecific reactivity in indirect antiglobulin tests, and 26% had positive direct antiglobulin tests after beginning treatment. This interference disappeared in all patients after discontinuing treatment. Papain panels avoided this reactivity and allowed us to identify alloantibodies. Phenotyped blood units were transfused, and no patient suffered any transfusion-related complications. CONCLUSION: Anti-CD38 MAs produce nonspecific interference in blood bank tests. This interference can be overcome by various methods, including DTT or papain treatment as proposed here. These methods have limitations that can be resolved using phenotyped blood units.

Prognostic value of antigen expression in multiple myeloma: a PETHEMA/GEM study on 1265 patients enrolled in four consecutive clinical trials.

Persistence of minimal residual disease (MRD) after treatment for myeloma predicts inferior outcomes, but within MRD-positive patients there is great heterogeneity with both early and very late relapses. Among different MRD techniques, flow cytometry provides additional information about antigen expression on tumor cells, which could potentially contribute to stratify MRD-positive patients. We investigated the prognostic value of those antigens required to monitor MRD in 1265 newly diagnosed patients enrolled in the GEM2000, GEM2005MENOS65, GEM2005MAS65 and GEM2010MAS65 protocols. Overall, CD19pos, CD27neg, CD38lo, CD45pos, CD81pos, CD117neg and CD138lo expression predicted inferior outcomes. Through principal component analysis, we found that simultaneous CD38lowCD81posCD117neg expression emerged as the most powerful combination with independent prognostic value for progression-free survival (HR:1.69; P=0.002). This unique phenotypic profile retained prognostic value among MRD-positive patients. We then used next-generation flow to determine antigen stability throughout the course of the disease, and found that the expression of antigens required to monitor MRD is mostly stable from diagnosis to MRD stages, except for CD81 whose expression progressively increased from baseline to chemoresistant tumor cells (14 vs 28%). Altogether, we showed that the phenotypic profile of tumor cells provides additional prognostic information, and could be used to further predict risk of relapse among MRD-positive patients.

Natural history of relapsed myeloma, refractory to immunomodulatory drugs and proteasome inhibitors: a multicenter IMWG study.

Introduction of new myeloma therapies offers new options for patients refractory to immunomodulatory drugs (IMiDs) and proteasome inhibitors (PIs). In this multicenter study, patients with relapsed multiple myeloma, who have received at least three prior lines of therapy, are refractory to both an IMiD (lenalidomide or pomalidomide) and a PI (bortezomib or carfilzomib), and have been exposed to an alkylating agent were identified. The time patients met the above criteria was defined as time zero (T0). Five hundred and forty-three patients diagnosed between 2006 and 2014 were enrolled in this study. Median age at T0 was 62 years (range 31-87); 61% were males. The median duration between diagnosis and T0 was 3.1 years. The median number of lines of therapy before T0 was 4 (range 3-13). The median overall survival (OS) from T0 for the entire cohort was 13 (95% confidence interval (CI) 11, 15) months. At least one regimen recorded after T0 in 462 (85%) patients, with a median (95% CI) progression-free survival and OS from T0 of 5 (4, 6), and 15.2 (13, 17) months, respectively. The study provides the expected outcome of relapsed multiple myeloma that is refractory to a PI and an IMiD, a benchmark for comparison of new therapies being evaluated.

Next Generation Flow for highly sensitive and standardized detection of minimal residual disease in multiple myeloma.

Flow cytometry has become a highly valuable method to monitor minimal residual disease (MRD) and evaluate the depth of complete response (CR) in bone marrow (BM) of multiple myeloma (MM) after therapy. However, current flow-MRD has lower sensitivity than molecular methods and lacks standardization. Here we report on a novel next generation flow (NGF) approach for highly sensitive and standardized MRD detection in MM. An optimized 2-tube 8-color antibody panel was constructed in five cycles of design-evaluation-redesign. In addition, a bulk-lysis procedure was established for acquisition of ⩾107 cells/sample, and novel software tools were constructed for automatic plasma cell gating. Multicenter evaluation of 110 follow-up BM from MM patients in very good partial response (VGPR) or CR showed a higher sensitivity for NGF-MRD vs conventional 8-color flow-MRD -MRD-positive rate of 47 vs 34% (P=0.003)-. Thus, 25% of patients classified as MRD-negative by conventional 8-color flow were MRD-positive by NGF, translating into a significantly longer progression-free survival for MRD-negative vs MRD-positive CR patients by NGF (75% progression-free survival not reached vs 7 months; P=0.02). This study establishes EuroFlow-based NGF as a highly sensitive, fully standardized approach for MRD detection in MM which overcomes the major limitations of conventional flow-MRD methods and is ready for implementation in routine diagnostics.

Bortezomib and thalidomide maintenance after stem cell transplantation for multiple myeloma: a PETHEMA/GEM trial.

The phase III trial GEM05MENOS65 randomized 390 patients 65 years old or younger with newly diagnosed symptomatic multiple myeloma (MM) to receive induction with thalidomide/dexamethasone, bortezomib/thalidomide/dexamethasone and Vincristine, BCNU, melphalan, cyclophosphamide, prednisone/vincristine, BCNU, doxorubicin, dexamethasone bortezomib (VBMCP/VBAD/B) followed by autologous stem cell transplantation (ASCT) with MEL-200. After ASCT, a second randomization was performed to compare thalidomide/bortezomib (TV), thalidomide (T) and alfa-2b interferon (alfa2-IFN). Maintenance treatment consisted of TV (thalidomide 100 mg daily plus one cycle of intravenous bortezomib at 1.3 mg/m2 on days 1, 4, 8 and 11 every 3 months) versus T (100 mg daily) versus alfa2-IFN (3 MU three times per week) for up to 3 years. A total of 271 patients were randomized (TV: 91; T: 88; alfa2-IFN: 92). The complete response (CR) rate with maintenance was improved by 21% with TV, 11% with T and 17% with alfa2-IFN (P, not significant). After a median follow-up of 58.6 months, the progression-free survival (PFS) was significantly longer with TV compared with T and alfa2-IFN (50.6 vs 40.3 vs 32.5 months, P=0.03). Overall survival was not significantly different among the three arms. Grade 2-3 peripheral neuropathy was observed in 48.8%, 34.4% and 1% of patients treated with TV, T and alfa2-IFN, respectively. In conclusion, bortezomib and thalidomide maintenance resulted in a significantly longer PFS when compared with thalidomide or alfa2-IFN. (no. EUDRA 2005-001110-41).

Second primary malignancies in multiple myeloma: an overview and IMWG consensus.

Background: Therapeutic advancements following the introduction of autologous stem cell transplantation and 'novel' agents have significantly improved clinical outcomes for patients with multiple myeloma (MM). Increased life expectancy, however, has led to renewed concerns about the long-term risk of second primary malignancies (SPMs). This review outlines the most up-to-date knowledge of possible host-, disease-, and treatment-related risk factors for the development of SPMs in patients with MM, and provides practical recommendations to assist physicians. Design: A Panel of International Myeloma Working Group members reviewed the most relevant data published in the literature as full papers, or presented at meetings of the American Society of Clinical Oncology, American Society of Hematology, European Hematology Association, or International Myeloma Workshops, up to June 2016. Here, we present the recommendations of the Panel, based on this literature review. Results: Overall, the risk of SPMs in MM is low, multifactorial, and partially related to the length of patients' survival and MM intrinsic susceptibility. Studies suggest a significantly increased incidence of SPMs when lenalidomide is administered either following, or concurrently with, oral melphalan. Increased SPM incidence has also been reported with lenalidomide maintenance following high-dose melphalan, albeit to a lesser degree. In both cases, the risk of death from MM was significantly higher than the risk of death from SPMs, with lenalidomide possibly providing a survival benefit. No increase in SPM incidence was reported with lenalidomide plus dexamethasone (without melphalan), or with bortezomib plus oral melphalan, dexamethasone, or thalidomide. Conclusion: In general, the risk of SPMs should not alter the current therapeutic decision-making process in MM. However, regimens such as lenalidomide plus dexamethasone should be preferred to prolonged exposure to lenalidomide plus oral melphalan. SPM risk should be carefully discussed with the patient in the context of benefits and risks of different treatment options.

Differentiation stage of myeloma plasma cells: biological and clinical significance.

The notion that plasma cells (PCs) are terminally differentiated has prevented intensive research in multiple myeloma (MM) about their phenotypic plasticity and differentiation. Here, we demonstrated in healthy individuals (n=20) that the CD19-CD81 expression axis identifies three bone marrow (BM)PC subsets with distinct age-prevalence, proliferation, replication-history, immunoglobulin-production, and phenotype, consistent with progressively increased differentiation from CD19+CD81+ into CD19-CD81+ and CD19-CD81- BMPCs. Afterwards, we demonstrated in 225 newly diagnosed MM patients that, comparing to normal BMPC counterparts, 59% had fully differentiated (CD19-CD81-) clones, 38% intermediate-differentiated (CD19-CD81+) and 3% less-differentiated (CD19+CD81+) clones. The latter patients had dismal outcome, and PC differentiation emerged as an independent prognostic marker for progression-free (HR: 1.7; P=0.005) and overall survival (HR: 2.1; P=0.006). Longitudinal comparison of diagnostic vs minimal-residual-disease samples (n=40) unraveled that in 20% of patients, less-differentiated PCs subclones become enriched after therapy-induced pressure. We also revealed that CD81 expression is epigenetically regulated, that less-differentiated clonal PCs retain high expression of genes related to preceding B-cell stages (for example: PAX5), and show distinct mutation profile vs fully differentiated PC clones within individual patients. Together, we shed new light into PC plasticity and demonstrated that MM patients harbouring less-differentiated PCs have dismal survival, which might be related to higher chemoresistant potential plus different molecular and genomic profiles.

Toxicity and efficacy of busulfan and fludarabine myeloablative conditioning for HLA-identical sibling allogeneic hematopoietic cell transplantation in AML and MDS.

The safety and efficacy of a 4-day myeloablative conditioning (MAC) regimen consisting of Bu 3.2 mg/kg and fludarabine 40 mg/m(2)/day for HLA-identical sibling allogeneic hematopoietic cell transplantation (HCT) in myeloid malignancies was investigated in 133 patients (median age, 47 years; range 19-74 years) with de novo AML (60%), secondary AML (20%) or myelodysplastic syndrome (20%). All patients engrafted. Hepatic veno-occlusive disease occurred in five patients (4%), and severe toxicities, mostly mucositis, occurred in twenty-three (17%) patients. The non-relapse mortality (NRM) at 100 days was 1.5%. The incidences of acute GVHD grade 2-4 and grade 3-4 were 32 and 13%, respectively. At a median follow-up of 38 months, the cumulative incidence of chronic GVHD was 67%. The relapse incidence was 30% (27 and 31%, respectively, in patients with early- and late-stage disease), and the overall NRM was 15%. The actuarial 4-year disease-free survival (DFS) and overall survival (OS) were 54 and 62%, respectively. Patients aged <50 years had better outcomes compared with older patients (DFS 64 vs 42%, P=0.006; OS 73 vs 47%, P<0.001, respectively).

Phenotypic identification of subclones in multiple myeloma with different chemoresistant, cytogenetic and clonogenic potential.

Knowledge about clonal diversity and selection is critical to understand multiple myeloma (MM) pathogenesis, chemoresistance and progression. If targeted therapy becomes reality, identification and monitoring of intraclonal plasma cell (PC) heterogeneity would become increasingly demanded. Here we investigated the kinetics of intraclonal heterogeneity among 116 MM patients using 23-marker multidimensional flow cytometry (MFC) and principal component analysis, at diagnosis and during minimal residual disease (MRD) monitoring. Distinct phenotypic subclones were observed in 35/116 (30%) newly diagnosed MM patients. In 10/35 patients, persistent MRD was detected after 9 induction cycles, and longitudinal comparison of patient-paired diagnostic vs MRD samples unraveled phenotypic clonal tiding after therapy in half (5/10) of the patients. After demonstrating selection of distinct phenotypic subsets by therapeutic pressure, we investigated whether distinct fluorescence-activated cell-sorted PC subclones had different clonogenic and cytogenetic profiles. In half (5/10) of the patients analyzed, distinct phenotypic subclones showed different clonogenic potential when co-cultured with stromal cells, and in 6/11 cases distinct phenotypic subclones displayed unique cytogenetic profiles by interphase fluorescence in situ hybridization, including selective del(17p13). Collectively, we unravel potential therapeutic selection of preexisting diagnostic phenotypic subclones during MRD monitoring; because phenotypically distinct PCs may show different clonogenic and cytogenetic profiles, identification and follow-up of unique phenotypic-genetic myeloma PC subclones may become relevant for tailored therapy.

New drugs and novel mechanisms of action in multiple myeloma in 2013: a report from the International Myeloma Working Group (IMWG).

Treatment in medical oncology is gradually shifting from the use of nonspecific chemotherapeutic agents toward an era of novel targeted therapy in which drugs and their combinations target specific aspects of the biology of tumor cells. Multiple myeloma (MM) has become one of the best examples in this regard, reflected in the identification of new pathogenic mechanisms, together with the development of novel drugs that are being explored from the preclinical setting to the early phases of clinical development. We review the biological rationale for the use of the most important new agents for treating MM and summarize their clinical activity in an increasingly busy field. First, we discuss data from already approved and active agents (including second- and third-generation proteasome inhibitors (PIs), immunomodulatory agents and alkylators). Next, we focus on agents with novel mechanisms of action, such as monoclonal antibodies (MoAbs), cell cycle-specific drugs, deacetylase inhibitors, agents acting on the unfolded protein response, signaling transduction pathway inhibitors and kinase inhibitors. Among this plethora of new agents or mechanisms, some are specially promising: anti-CD38 MoAb, such as daratumumab, are the first antibodies with clinical activity as single agents in MM. Moreover, the kinesin spindle protein inhibitor Arry-520 is effective in monotherapy as well as in combination with dexamethasone in heavily pretreated patients. Immunotherapy against MM is also being explored, and probably the most attractive example of this approach is the combination of the anti-CS1 MoAb elotuzumab with lenalidomide and dexamethasone, which has produced exciting results in the relapsed/refractory setting.

Critical evaluation of ASO RQ-PCR for minimal residual disease evaluation in multiple myeloma. A comparative analysis with flow cytometry.

We have analyzed the applicability, sensitivity and prognostic value of allele-specific oligonucleotide real-time quantitative PCR (ASO RQ-PCR) as a method for minimal residual disease (MRD) assessment in patients with multiple myeloma (MM), comparing the results with those of multiparameter flow cytometry (MFC). A total of 170 patients enrolled in three consecutive Spanish trials achieving at least partial response after treatment were included. Lack of clonality detection (n=31), unsuccessful sequencing (n=17) and suboptimal ASO performance (n=51) limited the applicability of PCR to 42% of cases. MRD was finally investigated in 103 patients (including 32 previously studied) with persistent disease identified by PCR and MFC in 54% and 46% of cases, respectively. A significant correlation in MRD quantitation by both the techniques was noted (r=0.881, P<0.001), being reflective of treatment intensity. Patients with <10(-4) residual tumor cells showed longer progression-free survival (PFS) compared with the rest (not reached (NR) vs 31 months, P=0.002), with similar results observed with MFC. Among complete responders (n=62), PCR discriminated two risk groups with different PFS (49 vs 26 months, P=0.001) and overall survival (NR vs 60 months, P=0.008). Thus, although less applicable than MFC, ASO RQ-PCR is a powerful technique to assess treatment efficacy and risk stratification in MM.

A multiparameter flow cytometry immunophenotypic algorithm for the identification of newly diagnosed symptomatic myeloma with an MGUS-like signature and long-term disease control.

Achieving complete remission (CR) in multiple myeloma (MM) translates into extended survival, but two subgroups of patients fall outside this paradigm: cases with unsustained CR, and patients that do not achieve CR but return into a monoclonal gammopathy of undetermined significance (MGUS)-like status with long-term survival. Here, we describe a novel automated flow cytometric classification focused on the analysis of the plasma-cell compartment to identify among newly diagnosed symptomatic MM patients (N=698) cases with a baseline MGUS-like profile, by comparing them to MGUS (N=497) patients and validating the classification model in 114 smoldering MM patients. Overall, 59 symptomatic MM patients (8%) showed an MGUS-like profile. Despite achieving similar CR rates after high-dose therapy/autologous stem cell transplantation vs other MM patients, MGUS-like cases had unprecedented longer time-to-progression (TTP) and overall survival (OS; ~60% at 10 years; P<0.001). Importantly, MGUS-like MM patients failing to achieve CR showed similar TTP (P=0.81) and OS (P=0.24) vs cases attaining CR. This automated classification also identified MGUS patients with shorter TTP (P=0.001, hazard ratio: 5.53) and ultra-high-risk smoldering MM (median TTP, 15 months). In summary, we have developed a biomarker that identifies a subset of symptomatic MM patients with an occult MGUS-like signature and an excellent outcome, independently of the depth of response.

Plasma cell leukemia: consensus statement on diagnostic requirements, response criteria and treatment recommendations by the International Myeloma Working Group.

Plasma cell leukemia (PCL) is a rare and aggressive variant of myeloma characterized by the presence of circulating plasma cells. It is classified as either primary PCL occurring at diagnosis or as secondary PCL in patients with relapsed/refractory myeloma. Primary PCL is a distinct clinic-pathological entity with different cytogenetic and molecular findings. The clinical course is aggressive with short remissions and survival duration. The diagnosis is based upon the percentage (≥ 20%) and absolute number (≥ 2 × 10(9)/l) of plasma cells in the peripheral blood. It is proposed that the thresholds for diagnosis be re-examined and consensus recommendations are made for diagnosis, as well as, response and progression criteria. Induction therapy needs to begin promptly and have high clinical activity leading to rapid disease control in an effort to minimize the risk of early death. Intensive chemotherapy regimens and bortezomib-based regimens are recommended followed by high-dose therapy with autologous stem cell transplantation if feasible. Allogeneic transplantation can be considered in younger patients. Prospective multicenter studies are required to provide revised definitions and better understanding of the pathogenesis of PCL.

Clinical significance of CD81 expression by clonal plasma cells in high-risk smoldering and symptomatic multiple myeloma patients.

The presence of CD19 in myelomatous plasma cells (MM-PCs) correlates with adverse prognosis in multiple myeloma (MM). Although CD19 expression is upregulated by CD81, this marker has been poorly investigated and its prognostic value in MM remains unknown. We have analyzed CD81 expression by multiparameter flow cytometry in MM-PCs from 230 MM patients at diagnosis included in the Grupo Español de Mieloma (GEM)05>65 years trial as well as 56 high-risk smoldering MM (SMM). CD81 expression was detected in 45% (103/230) MM patients, and the detection of CD81(+) MM-PC was an independent prognostic factor for progression-free (hazard ratio=1.9; P=0.003) and overall survival (hazard ratio=2.0; P=0.02); this adverse impact was validated in an additional series of 325 transplant-candidate MM patients included in the GEM05 <65 years trial. Moreover, CD81(+) SMM (n=34/56, 57%) patients had a shorter time to progression to MM (P=0.02). Overall, our results show that CD81 may have a relevant role in MM pathogenesis and represent a novel adverse prognostic marker in myeloma.

Risk of progression and survival in multiple myeloma relapsing after therapy with IMiDs and bortezomib: a multicenter international myeloma working group study.

Promising new drugs are being evaluated for treatment of multiple myeloma (MM), but their impact should be measured against the expected outcome in patients failing current therapies. However, the natural history of relapsed disease in the current era remains unclear. We studied 286 patients with relapsed MM, who were refractory to bortezomib and were relapsed following, refractory to or ineligible to receive, an IMiD (immunomodulatory drug), had measurable disease, and ECOG PS of 0, 1 or 2. The date patients satisfied the entry criteria was defined as time zero (T(0)). The median age at diagnosis was 58 years, and time from diagnosis to T(0) was 3.3 years. Following T(0), 213 (74%) patients had a treatment recorded with one or more regimens (median=1; range 0-8). The first regimen contained bortezomib in 55 (26%) patients and an IMiD in 70 (33%). A minor response or better was seen to at least one therapy after T(0) in 94 patients (44%) including ≥ partial response in 69 (32%). The median overall survival and event-free survival from T(0) were 9 and 5 months, respectively. This study confirms the poor outcome, once patients become refractory to current treatments. The results provide context for interpreting ongoing trials of new drugs.

Management of treatment-emergent peripheral neuropathy in multiple myeloma.

Peripheral neuropathy (PN) is one of the most important complications of multiple myeloma (MM) treatment. PN can be caused by MM itself, either by the effects of the monoclonal protein or in the form of radiculopathy from direct compression, and particularly by certain therapies, including bortezomib, thalidomide, vinca alkaloids and cisplatin. Clinical evaluation has shown that up to 20% of MM patients have PN at diagnosis and as many as 75% may experience treatment-emergent PN during therapy. The incidence, symptoms, reversibility, predisposing factors and etiology of treatment-emergent PN vary among MM therapies, with PN incidence also affected by the dose, schedule and combinations of potentially neurotoxic agents. Effective management of treatment-emergent PN is critical to minimize the incidence and severity of this complication, while maintaining therapeutic efficacy. Herein, the state of knowledge regarding treatment-emergent PN in MM patients and current management practices are outlined, and recommendations regarding optimal strategies for PN management during MM treatment are provided. These strategies include early and regular monitoring with neurological evaluation, with dose modification and treatment discontinuation as indicated. Areas requiring further research include the development of MM-specific, patient-focused assessment tools, pharmacogenomic analysis of patient DNA, and trials to assess the efficacy of pharmacological interventions.